Okay. 0:02 Hi everybody. 0:02 Looks like the last few people are coming in. 0:04 So I think we're set to go. 0:06 Good afternoon and thank you for joining me here today. 0:08 My name is Ben Jakuben. 0:11 Today we're gonna talk about jump starting 0:13 your app development using open source software. 0:14 I'm a teacher at Treehouse. 0:17 We're an online education company. 0:19 And, I teach, primarily Android development and 0:21 a little bit of iOS development as well. 0:24 And we cover, besides app development, we 0:28 cover front end and back end web development. 0:30 And there's stuff on the back table there. 0:33 So on your way out walk by there and we've got some notebooks, stickers and some. 0:36 Cards for free trials so if you wanna give us a shoot we got a free month 0:41 we're at nutrition base video learn platform so, take 0:45 a card or just visit the website for free 0:49 trial and check us out, some of the stuff 0:51 we're gonna cover today is, we, we have full 0:53 length courses of video on, on the site as 0:56 well so you can follow there if you're interested. 0:58 ss Okay, so, why specifically did I, want 1:01 to talk about using open source software today? 1:04 Actuall [COUGH]. 1:07 Well, so, before we get into it. 1:09 [LAUGH] I wanted to ask what everybody's experience 1:13 was with mobile development and open source software. 1:15 So just with a quick show of hands, can you show me how many of you have. 1:18 A little bit of Android experience? 1:23 Okay, and how about a lot of Android experience? 1:26 A few, okay. 1:28 And then, for iOS as well, how about a little bit if iOS experience. 1:29 Okay, and a lot of iOS experience? 1:33 Good, Good. 1:35 How many are currently using open source software 1:36 in some way or another in their projects? 1:39 Good, all right so, [LAUGH] I don't have to tell you too much about the why then, 1:43 but this is just one of my favorite quotes 1:47 from an open source advocate named Eric S Raymond. 1:49 This is from an early essay on open source software called Cathedral and the Bazaar. 1:52 And quote is just good programmers know, what to write but great ones know 1:55 what to rewrite and reuse and it's that reuse part that really speaks to me. 1:59 The other thing is you you don't really need 2:04 to do work that somebody else has already done. 2:07 if, [LAUGH] if, if they've already done it and it's been done better. 2:10 And it's being used and it's well tested. 2:13 Unless you wanna, learn more about it yourself but, if 2:16 you need to get something out the door and save time. 2:19 And wanna use something that's proven and trusted. 2:21 Then, that's when open sores can really help you out. 2:24 So yes, specifically just run through some of the pros and cons. 2:28 One of the things I really like about, using open 2:31 source software is that third bullet point learning from others. 2:34 Taking a look at how other people are writing code is, the best 2:38 way to figure out where I'm doing it wrong and where I can improve. 2:41 So, pulling down an open source library and looking at either 2:44 example projects or how they're, implementing what they're doing is a. 2:48 Great way for me to figure out how I could make myself a better programmer. 2:51 Speaking of development, making the world a better 2:55 place of course by, helping each other out. 2:57 another, are some disadvantages as well. 3:00 I'm sure, a lot of you have may have been bitten by some 3:03 of these specifically if you're using an open source library that gets abandoned. 3:05 It's very frustrated if you need to. 3:10 you, if you discover a bug or some update to your 3:13 platform comes out and your library you're using is no longer supported. 3:16 So you need to either, fix it yourself or find an alternative. 3:19 On the flip side of that, sometimes, a good 3:24 open source library will get sucked into the platform. 3:26 So for example, pull the refresh, there were a ton of open 3:29 source implementations of the pull to refresh control on both iOS and Android. 3:32 And now, both of those both platforms have a 3:36 pull or swipe to refresh control built into the APIs. 3:39 So, you still have to do some conversion, but it may be a little bit easier to 3:42 do it that way than trying to, come up with your own or fix somebody else's code. 3:47 The second bullet point might be hard to include, that. 3:53 Isn't quite as true so much anymore 3:57 with things like, Girdle and CocoaPods for dependency 3:59 management which we're gonna talk about in just 4:02 a minute, it's a lot easier to include 4:03 homosource projects in your own projects, but, 4:06 before such tools it, it was cumbersome there 4:10 was a, Of popular open source library called 4:13 320 for iOS and this is by Facebook. 4:17 An early version of the SDK. 4:20 And the documentation was, really long on how to 4:23 include in your project and you had to include like 4:27 15 different frameworks and you had to wire things up 4:29 and you had to set your flags a certain way. 4:31 And it was right with steps to fail, but now it's a one line CocoaPod. 4:34 You just pull it in and, and all the hard work is taken care of for you. 4:38 It's in your project and you can use it right 4:41 away, so, it's Thank goodness, [LAUGH] tools like that exist nowadays. 4:43 Another thing, this is an important one that, that I forget sometimes, but it's 4:50 Really important to remember is, open source does not just mean for your code. 4:56 Whether it's design assets you're after or photos or other materials you 5:00 wanna use within an app even, music or video, stock footage, things 5:04 like that you can really, add to the richness of your app 5:08 with the open source or the open license, like Creative Commons license. 5:11 Things that you can include as long as you. 5:16 Attribute it specifically and make sure that you follow the, open 5:18 source license that are set aside for those kind of things. 5:22 >> [COUGH]. 5:25 >> And a specific example of this, I let's see. 5:27 Yesterday, I did a workshop on iOS and, Android development. 5:31 And, we developed a, very simple basic. 5:35 Weather app and I needed to get some weather icons for it and 5:39 I am not a designer, so I did not want to, draw anything myself. 5:42 So I took a look, I did a Google search 5:45 and there are plenty of free weather icons, of course. 5:47 Then I went to GitHub and took a look 5:50 as well, and I'm just gonna switch over to show, 5:52 Oh, let's see, let me go to GitHub and do it. 5:58 I just searched for weather icons and sure enough there are 6:00 a bunch of solutions for both, mobile platforms and the web. 6:03 I ended up taking, some of these from Kickstand 6:07 apps weather icons and they had these available in 6:10 PNG or SVG format and they're free to use 6:15 in your apps, free to modify as long as you. 6:17 Give them credit that you use their resources. 6:20 So, again, it's just a fantastic time saver, 6:22 whether you're, you know, using this to prototype 6:24 something quickly or if, if it's good enough 6:27 you that wanna use it in your final app. 6:29 You know, maybe you don't have design team that can, pump out 6:30 some assets for you quickly or maybe you don't wanna do it yourself. 6:32 [BLANK_AUDIO] 6:35 Okay, so briefly for the rest of the 6:41 talk here, we're gonna talk about three main things. 6:43 How do we know what's available, then how do 6:47 we add it to our projects, and then I'll just 6:49 give a, quick rundown of some of my, personal favorite 6:51 open source libraries I use in some of my projects. 6:54 [NOISE]. 6:57 [LAUGH] so, one thing when you're just starting out. 6:59 Whether you're, a new developer or it's your first 7:03 time trying to find open source code you wanna use. 7:06 The question is, like, how do you even know what's out there. 7:09 And that's, with more and more coming out. 7:12 Every week it seems. 7:15 It's hard to stay on top of the constant flow of, new things to 7:16 try out, new controls and new things you wanna, include in your product somehow. 7:20 So what I try to do is, every time I sit down to, like implement 7:27 a new feature or maybe improve something 7:30 I ask myself, has somebody done this already. 7:32 And, I ask myself and I will ask other resources as well. 7:35 I'll go to Google and I can type in the specific question like. 7:39 Let's take an example. 7:42 Excuse me, let's say, what's the best way to download images in Android? 7:46 You know, maybe I'm not familiar with some image downloading libraries I wanna know. 7:54 So sure enough there are some posts on stack over flow. 7:57 And if we click on the first one here and we scroll down to the answer. 8:00 And this person recommends, a library and we link to it. 8:04 And it's one called Universal Image Loader. 8:08 Okay, so this, looks like it will be useful for us. 8:10 It looks like it might be a good solution. 8:12 But then the next question I ask is, okay. 8:13 This is it's, it's pretty active. 8:16 We know that the last contribution was, was 8:18 about five days ago but, is there something better. 8:20 [BLANK_AUDIO] 8:24 So, then I remembered the most, the two 8:27 most important letters when researching open source libraries, versus. 8:29 And what I mean by that is, I will take the library name. 8:34 And then, start typing for Google Auto 8:38 Complete so this is Android Universal Image Loader, 8:40 and start typing a versus and sure enough 8:46 we get some alternatives because inevitable people will 8:49 compare the different options for us so unless 8:52 it's something brand new you can usually find. 8:54 Some good information, some good comparisons, maybe some benchmarks. 8:57 And this is useful as well because It's one thing to just find 9:01 and discover a library, but it's another to know that it's, useful for others. 9:06 That it's out there in the wild, that it's used 9:10 in apps and that other people have experience with it. 9:12 Because you wanna have something that's not gonna break on you. 9:13 You wanna, have something that maybe is in, 9:15 in use in popular apps with lots of downloads. 9:17 So in this example, we get a link to 9:21 another one that compared Picasso versus Universal Image Loader. 9:24 And if we look there, we can see, some additional information. 9:27 And then there's some additional recommendations as well. 9:31 Volley from Google and You are image view helper. 9:34 So the point is, you can kind of get lost in 9:39 the rabbit hole, looking through you know, looking for the best library. 9:41 But if you can, narrow it down to a few choices. 9:45 Get some information from the web, or maybe from some people you know. 9:48 Then you can go from there and try it out. 9:50 I'm gonna go back just a step here. 9:52 That's the other thing. 9:57 You know, asking real people for help. 9:58 So when I'm, again, when I'm, trying to find out something to do, 10:00 I'll ask some of the developers I work with, the Treehouse, for their experience. 10:04 We have a mobile team. 10:08 So they're a great resource there, on the cutting edge. 10:10 Working on our Treehouse Mobile Apps for Android and iOS. 10:13 And I can just ask them, like, hey, by the 10:15 way, have you been, you know, using anything for video streaming? 10:17 Which is something we do. 10:20 So, then we can get some information and they can point me in the right direction. 10:21 That's one of the big things I learned early on as a software developer was that. 10:26 There are so many people smarter than me and better than me at it. 10:31 So, I will try and make use of their knowledge rather than yeah, 10:34 reinvent the wheel again and try and figure things out on my own. 10:38 I will gladly accept, advice from somebody I know who's a reliable source. 10:40 All right, and the last one here is ask me. 10:45 On each slide I've got my Twitter handle. 10:47 So find me at Twitter. 10:49 Maybe Google Plus. 10:50 If you're a member of Treehouse, we have a Treehouse forum where we 10:52 discuss, you know, questions about the 10:56 material we're covering or anything in general. 10:58 So, I may not have an answer, but maybe I can help 10:59 you, get in touch with someone who does have an answer for you. 11:02 [SOUND]. 11:04 Okay, and the other thing, So besides, you know, starting out 11:10 on something and, and trying to figure out you know, from scratch 11:14 what you wanna do, Another way to To stay in the 11:19 know is to, keep tabs on what is being released, what's available. 11:23 And it doesn't have to be a lot of effort. 11:28 The way I do it, you know whether or not this 11:30 would work for you is I follow certain people on Twitter 11:32 and I have a curated list for Android developers, and a 11:35 curated list for iOS developers, which if you're interested find me on. 11:37 Twitter and subscribe to those lists as well. 11:40 And it's things that you know, we'll talk about when 11:43 a new, specific library is released or, maybe, some helpful tips. 11:46 I've got two red, two newsletters [INAUDIBLE] there. 11:50 A couple different newsletters for both Android and iOS. 11:52 These are my two personal favorites. 11:55 Android Weekly. 11:58 That, both of them are weekly newsletters, but they just go out and curate the week's 11:58 latest posts, or sometimes new libraries, things that 12:03 are, of interest for Android and iOS development. 12:06 And what I'll do, I'll go through, check the newsletter. 12:09 I may not read anything in the newsletter, but, I'll at least bookmark things 12:12 that look interesting so I can either read about them later or use them later. 12:15 The last list here is to let others do the discovery work. 12:20 Again, letting, other people curate lists for you. 12:23 There's a couple web, websites listed here that I'll refer to 12:26 when I wanna find out, more about what might be available. 12:28 So the first one here is, called Android Arsenal, and this 12:32 is a pretty extensive list of, free libraries and tools for Android. 12:35 And if you scroll through, we can take 12:38 a look at, just everything from, you know, lower 12:40 level, lower level networking and cloud services to, controls 12:43 like date-pickers and animations and, et cetera for here. 12:46 And then the same thing for iOS is one called iOS Cosmos which 12:50 is a very similar, a lot of things about, graphics and networking, et cetera. 12:54 And then the last two I had listed were Cocoa Controls is one that's 12:59 specific for a UI controls for iOS and Active Wiki is another one that's similar 13:05 to the first two, that has a whole bunch of information about, both platforms about 13:10 libraries you can use and, and other 13:14 resources to help with, development on both platforms. 13:15 [NOISE] So of course when you think open source software you think of GitHub 13:18 which is, the most popular repository for open source libraries. 13:23 It's certainly not the only one. 13:29 But, that's another place I will go when I wanna 13:30 look for help, I may just want to look for. 13:32 Browse through and explore. 13:35 And here's a couple different ways you can, you can 13:37 look for just try and, find information that maybe help. 13:39 But you know whether you're, looking for a targeted search for something or 13:41 maybe just want to again, spend a few minutes getting to know what's available. 13:45 So if you go to, let's see. 13:49 Let's just go to GitHub. 13:53 And specifically if we go to explorer, they have 13:55 a bunch of different categories you can look through. 13:59 So if you're interested in something specific, you can come here. 14:01 But I like to go to, the trending, repositories as well. 14:04 And you can filter by languages. 14:07 So let's go down and let's filter by 14:10 Let's talk about Swift and see what the latest 14:16 things available are for, Apple's new programming language called Swift. 14:19 So here you can see you know, this is something that's brand new. 14:25 It's only been out for a few weeks, and already people are, creating 14:27 libraries and sharing them, creating sample projects 14:30 of how you wanna do certain things. 14:33 Here's one. 14:34 The second one here is called Swifter, it's a 14:35 Twitter framework for iOS and OS X written in swift. 14:36 So this is, you know, this is something you might wanna use in your app. 14:41 You know, if it's something that, that you need hep, 14:45 doing or maybe, again, example code that you can learn from. 14:47 So if you So we just wanna get up to speed with the new language. 14:50 You can come up to here and see some project that people are already running. 14:53 Download it, put it in Xcode and take a look of how they are things. 14:57 Sorry, I am getting a little, distracted by the, the volume next door. 15:01 okay, yeah, and then lastly, if you wanna search for any thing specific, so for 15:06 example were gonna cover How to consume rest based APIs in both Android and iOS. 15:12 So if we wanna look for iOS REST, 15:18 for example, let's just look in this repository. 15:19 I've got a switch to all repositories. 15:23 But we'll do the same thing iOS REST, 15:25 then we see some recommendations for some, REST-based 15:28 libraries for iOS, or the same thing for Android, if you want to go that route. 15:31 So all right, so that's enough about like, how to find things. 15:35 Again, moving on how to, once we find something, 15:43 how do we add it to our own projects. 15:47 And this is where for both platforms, it's so much easier than 15:49 it used to be, thanks to Girdle for Android and CocoaPods for iOS. 15:52 So I'm gonna start by talking about Android and we're 15:56 gonna look at Girdle and go through some, some popular 15:59 Android libraries and then we'll spend a little bit of 16:02 time on iOS and wrap up for questions at the end. 16:04 So just another show of hands, how many 16:09 of you are using Android Studio for Android development? 16:12 Okay. 16:16 And how many of you are using Eclipse still? 16:17 So, for Eclipse, 16:21 we would either, have to download a Ajax file or maybe 16:24 we could hook into Maven and pull in a library that way. 16:29 For Android studios we've got a new built system called gradle, and 16:33 it's a tool for automated project films, it needs to know everything 16:36 a project needs to be builter on and it also packages that 16:39 all up into and pulls it all together, downloads it from a. 16:42 It's a fantastic this is what im most excited about with Girdle 16:46 with Android studios specifically, It's just a one line One line you need 16:50 to add to your, build.girdle file, and you can pull in a specific 16:55 version of an open source library from a repository such as Maven Central. 16:58 And so many popular libraries are moving to this 17:03 format where it's so easy to just pull it in. 17:07 they're, in the repository or 17:10 To just download it, you can include from a 17:15 local repository to, I'm sorry, that's what I'm trying 17:16 to say. 17:21 All right. 17:22 So moving on, these are some of my, favorite libraries. 17:22 The first one here in the middle is called, Butter Knife. 17:26 And that's from developer, Jake Wharton, who works at Square. 17:29 We're gonna talk about Square a lot. 17:33 Square has some fantastic libraries available. 17:34 For open source for your apps. 17:37 Specifically for Android, they seem to have more for Android 17:39 than iOS, but there are some available for iOS as well. 17:42 In the upper right is a square library 17:45 called Picasso, and that's used for image loading. 17:46 The bottom right is one called list view animations, and it's 17:49 to do a whole bunch of different animations for list views. 17:53 So you know, list view is a very common element for Displaying data in Android. 17:56 And pardon me, there is a bunch of default animations you could tie in pretty easily. 18:03 Vertical movement, horizontal movement, having items slide up, having items fade 18:11 off as you, as they stroll toward the bottom on the list. 18:15 You know, I implemented some of that on my own and. 18:19 It's, it's ok but to be able to pull on a 18:22 library and just start using it is, again so much easier. 18:24 Bottom left here is called Retro Fit. 18:27 That is a, type safe rest client for Android and Java. 18:29 Were gonna walk through an example of that specifically but it's 18:32 a really nice, clean interface to use for consuming a REST API. 18:36 It uses some Java annotation's and it's a nice simple way to call a specific 18:40 API and then have that data translated for you into object models. 18:46 It uses, Retro fit uses library, another library called JSON which is JSON parsing. 18:53 And under the hood it converts your big 18:59 JSON document into specific Java object models which 19:01 is then makes it a lot easier to use in your app or persist your data. 19:05 The upper left is just example of a good UI library that's easy to tie into. 19:09 It isn't, this is a cards library, it's called CardsLib 19:15 and it's not particularly hard to implement your own, card interface. 19:18 It's just a box or rectangle, but this is 19:22 already done with a bunch of different formatting options and 19:24 again just to pull it in, it's a really 19:26 simple way to get some nice cards you can use. 19:28 [SOUND] Okay, so, I'm gonna start by looking at no, I got ahead of myself. 19:34 I'm gonna skip Picasso, and let's take a look at Butter Knife first. 19:39 So I've concocted an example here. 19:42 And this example is a little bit contrived just to, demonstrate. 19:45 But it is representative of a real world use of Butter Knife. 19:50 So here I've got a layout with a bunch of different controls on it. 19:54 I know this is cluttered. 19:58 It looks like an Android App from 2009. 19:59 But what we can do is reduce a lot of the boilerplate clode, 20:01 boilerplate code that we need to get access to those elements in the layout. 20:05 So just with the regular entered STK, we need to declare 20:11 all of our variables, call findViewById to get them from the layout. 20:15 And cast them to the appropriate view subtype 20:20 and then store them, maybe setting clis, setOnClickListener like 20:23 this with, this is an anonymous inner class here 20:26 for the OnClickListener which calls a method down here. 20:29 Using the magic of Butter Knife let's take a look at the website itself. 20:32 This is Butter Knife repository on GitHub. 20:39 And there's, it's a View Injection Library, so it's pretty lightweight. 20:42 So it's just a second about injections. 20:47 So this is a way to inject your views into the into your 20:50 activity and it's a lightweight version of something called Dependency Injection. 20:56 There's another open source library. 21:01 I'm not gonna talk about it specifically, but I wanna mention it just so, if 21:03 it is something that you need you can, you can look into it on your own. 21:06 But here the Butter Knife is like a Dagger, only infinitely less sharp. 21:10 Dagger is one of those Square Open 21:15 Source libraries that's used for Dependency Injection. 21:17 And that can be really useful if you wanna have for example 21:19 one thing I've used before is a versioning of clients of web services. 21:22 So I may have version one with an implementation and an interface, 21:27 and then I'll inject it into my activity where I need it. 21:32 But then if I need to roll up for version two, I can inject the 21:35 different version just with a simple change of the a line of code for Dagger. 21:38 But back to Butter Knife I'm gonna cheat here, just copy and paste and code. 21:44 But the idea is we can take all of 21:49 this boilerplate code and replace it with some injections. 21:52 And I'm gonna need to pull in the library as well. 21:57 I, I skipped the step here, but this is our new code. 22:02 I'm getting some errors because I haven't yet pulled Butter Knife into my project. 22:07 But it's super easy to do. 22:10 Thanks to Gradle. 22:12 So if we scroll down we can see here would be the, how 22:13 we wanna define a dependency using Maven, if we're doing this in Eclipse. 22:16 But with Gradle, we just add this one line to our file. 22:21 I'm gonna go to Android Studio. 22:25 And I've got the build.gradle file. 22:27 And I wanna point out that, yeah, in Android Studio if, if this is if 22:29 you haven't used it before an Android 22:34 Studio project can have multiple modules within it. 22:36 So I've got this project called Open Source Demo and inside is my app module. 22:39 And that's the actual app. 22:43 But you can have additional modules if you have other projects, maybe 22:44 a test project, or maybe a library project that you wanna reference. 22:47 So each project has its own Gradle file. 22:51 And you wanna make sure you put it in the right one. 22:52 There is a wrapper Gradle file here at the parent level, if I collapse this. 22:54 This one here is a top level build file and 23:00 this is to add configuration options for all your modules. 23:02 But I'm just working in the app module, so 23:06 I'm gonna close this one and go back in here. 23:07 And I, I already have line in here that we'll use in a 23:11 few minutes, but I'm gonna paste in that line I just copied from GitHub. 23:14 And this is how I am including version 5.1.0 of Butter Knife. 23:17 So now, sure enough, if I go back here, well, I still 23:22 have the errors because now I need to sync those changes to Gradle. 23:26 And I get a warning here it says Gradle files have changed. 23:29 So every time you make a change to Gradle we need to sync it. 23:32 So there's a link here for the button up here 23:37 with the little Gradle logo, sync project with Gradle files. 23:40 And the reason we need that is because the line that we added, the compile line 23:43 is saying that we want to pull in that library and use it in the project. 23:49 And our project doesn't have it yet. 23:53 So by syncing the Gradle files, Gradle runs, it 23:54 uses that reference to go down, pull that appropriate version. 23:57 And now it's in our project. 24:00 Now that the sink is complete, now I can go back to 24:01 main activity and take a look at how to use Butter Knife. 24:03 So, specifically here are the annotations I was talking about. 24:07 To inject the view we annotate it with @InjectView. 24:11 We pass in the ID, and then we just declare it up here. 24:14 So now we've taken seven lines that were in 24:17 the onCreate method, and gotten rid of those, and, 24:20 just by adding this, this InjectView in front of 24:23 each member variable in the class at the top. 24:25 It just makes the code a lot easier, a lot smaller more organized. 24:27 likewise, I really like this for the OnClickListeners. 24:33 You know everybody seems to have their own method for doing OnClickListeners or 24:35 anonymous inner classes when they're attaching listeners 24:39 or, or whatever to their UI elements. 24:42 This way you just inject it with the onClick attribute 24:46 and you specify the object that you are attaching it to. 24:50 And this is the method that gets run on the onClick. 24:53 And this one is just starting the new activity. 24:56 So there you can see our onCreate method is very clean and reduced. 24:59 The key here is to use the call ButterKnife.inject. 25:03 You pass in the current context, and that 25:07 has to happen before the call to setContentView. 25:09 So that's why it's between the super call and setContentView. 25:12 But that takes care of it. 25:17 That wires everything up. 25:19 And now we can reference our layout elements in code, just like anything else. 25:20 So I can say m hello world label, and set the text equal to goodbye instead. 25:25 Oops, a little bit of Objective C stuck, snuck in there. 25:31 Okay. 25:36 [SOUND] All right. 25:37 So now I'm gonna go back to Picasso. 25:44 Here we go. 25:47 And this is 25:50 a very convenient image loading library. 25:54 Without Picasso, downloading images in Android is cumbersome. 25:56 You have to get the image URL, create an AsyncTask, which is a little bit complex. 26:02 There are different methods you need to override and make sure 26:07 you call it from the right place store the result in 26:10 bitmap, and then you're responsible for caching that image yourself, if 26:12 you wanna cache it to avoid a network call each time. 26:15 Well, all of that is handled automatically with Picasso. 26:18 You include the library using one line in Gradle just like 26:20 we saw, and then with the image URL you add one line. 26:24 Now, it's configurable, there's different ways you can load the ImageView but as 26:28 we'll see with this example, you just load it into an existing ImageView. 26:32 We don't need to replace any of the ImageView element itself. 26:35 We can use existing ImageViews. 26:39 It's, it's built right on top of that. 26:41 So I'm gonna go to the Picasso GitHub page. 26:44 oh, and that's right. 26:50 This one doesn't have that specific Gradle line 26:52 that we need, but it's the same pattern. 26:56 All of the Square Open Source libraries 26:59 are available through made in Central like this. 27:01 So we can go back to our build file and. 27:04 [BLANK_AUDIO] 27:08 I'm gonna add another line to Import Picasso. 27:12 And pardon me for just a second, I got the note here on my phone. 27:16 Here we go. 27:20 So we're compiling com.squareup.picasso, and we're 27:21 on version [SOUND] com Picasso, version 2.3.2. 27:29 Okay? 27:36 And I'm gonna sync these changes with Gradle again, using this button up here. 27:36 And I get my messages down at the bottom, Gradle's executing, and hit complete. 27:43 Okay. 27:48 So now I go into main activity 27:48 and I'm going to replace my image. 27:52 Here I've got an image of one time machine, a TARDIS. 27:54 So, instead, let's replace it with image of another time machine. 27:58 Let's use this DeLorean here instead. 28:00 So, back in my activity. 28:04 Pardon me. 28:08 We're gonna use the line just like we saw on the slide. 28:10 We used the Picasso library. 28:13 And then, we, the first thing we passed in was the context. 28:16 And, it has this nice method signature. 28:18 So with the context, it's very it, it reads very clearly, like English. 28:22 We're saying, okay, with this context, load this URL. 28:27 And I'm just gonna paste in that URL I grabbed. 28:31 And load it where? 28:34 Load it into our ImageView. 28:34 And I already have an ImageView here call it M Tardis ImageView. 28:37 And if we do that, then it's going to 28:43 take care of loading that image asynchronously in the background. 28:47 And then it's gonna cache it on the device for us as 28:50 well, so that we don't have to make that network call again. 28:52 So let's just, I think if we run this, 28:55 we should be able to see [SOUND] the ImageView. 28:59 Now I am using just a side note how 29:05 many of you are using Genymotion in your area development? 29:08 Now, I see only one hand. 29:14 Okay. 29:14 So [APPLAUSE] if nothing else out of this talk, 29:15 please check out Genymotion, it is a fantastic resource. 29:18 It's so much better than the stock emulator. 29:21 And they have a bunch of different images of, like real devices available. 29:27 So if you wanna test higher app runs on a Nexus or a Samsung device or 29:31 an HTC device, you can download different images 29:35 and then run them as devices on your machine. 29:38 That looks like, I'm not sure. 29:42 I don't want to spend too much time troubleshooting. 29:48 I was just gonna run it to see. 29:51 But all right, well let's skip ahead, we'll come back to that if we need to. 29:53 So we're gonna keep going through, a couple more libraries as well. 29:57 oh, skip ahead here. 30:05 Pardon me for just a second. 30:07 I'm gonna go back here. 30:09 The next one I wanted to, to demonstrate was Retrofit. 30:11 This is that REST client for Android. 30:14 And that's the line that was already in our build file, 30:16 so if we go there and take a look at build.Gradle. 30:21 Here's the line to get version 1.6 of Retrofit. 30:25 And to use it 30:30 [BLANK_AUDIO] 30:31 we need to declare. 30:35 Here I've got a services package. 30:37 So we've got an interface here, which is the, for service that we're consuming. 30:39 So I'm gonna use a REST API from forecast.io. 30:43 And let's take a quick look at what is, what that looks like. 30:47 So this is just a free API to use and it's, it's pretty complex JSON. 30:51 The reason I wanted to use it was it's an example of 30:55 a complex payload with all these nested objects and arrays of objects. 30:58 so, if we scroll through this is just current, 31:04 current weather conditions and a longer forecast, et cetera. 31:08 So the format of the request is you pass 31:12 in your key and then the latitude and longitude. 31:15 So if we get back to the code we see it has an 31:19 annotation, this is a getMethod and also you can use post as well. 31:22 And then you give the, the format of your API 31:26 call, which is what we just saw key, latitude, longitude. 31:29 And then we map the parameters here. 31:34 We have the, a method called get forecast async and it maps 31:36 these key lat and long parameters to those items from the paths. 31:40 So you can see the, the curly 31:44 braces around the parameter names match down here. 31:46 And that uses the callback mechanism because 31:49 once again this is an asynchronous call. 31:51 It's gonna make the weather forecast call and come back, 31:52 call this callback and then we can handle the response. 31:56 So, we have this is just the interface itself, but the next class is the client. 31:59 This is the implementation of the interface and here we've got the base URL 32:03 we need, the key, and this is what where the real work is done. 32:07 We use the Retrofit REST adapter class. 32:13 We create a new one using the builder. 32:17 We set the end points. 32:19 And build, this is an optional logging parameter, which if we 32:20 saw down there you can see quite a lot of information from the Retrofit call. 32:26 And then we set we create it for the forecast service class. 32:32 That's the interface that we just looked at. 32:37 And then we've got a method here to get the forecast 32:40 data where we pass in the latitude, longitude, and a callback. 32:42 So then, to call it from our activity and I know I'm, I'm kind 32:45 of going through this fast, but if you want to take a look at 32:48 this code and use it as an, an example I will share these slides 32:51 and make the repo available on GitHub for you to look at as well. 32:54 Cuz for me again, best way to learn is 32:58 by looking at an example that's, you know, how 33:00 I practice Retrofit was looking at examples apps that 33:01 used it and reading a little bit about the documentation. 33:04 So here in main activity 33:07 actually I forgot I put it in a different activity. 33:13 So I've got a second activity called Forecast Activity. 33:14 And all I wanna do is show current temperature in a label here in the middle. 33:17 So here we use our forecast client app. 33:24 It's a singleton instance of just the forecast service. 33:26 And then we call the get forecast data. 33:31 This is latitude and longitude of Las Vegas. 33:34 And then we pass in the callback. 33:38 And this is a Retrofit callback. 33:39 And it has a forecast object. 33:42 So before we, we'll come back to that in just one second. 33:47 The, the format of the callback is simply success or failure. 33:49 So if it comes back with a success, we get the object model to match. 33:53 And we get a Retrofit response, so we can investigate it as well. 33:57 Otherwise, we get the error and we can handle the error if we need to. 34:00 So about that model. 34:04 We had that complex JSON and we need our Java representations of it. 34:05 Now if we wanted to hand-code our 34:13 Java representations it would be pretty tedious. 34:15 If I go to the model's package here and I take a look at all of this. 34:18 I did not code this by hand, thank God. 34:21 You know, it's just a bunch of getters 34:24 and setters and member variables, and things like that. 34:26 What I used was a generator and there are 34:29 some helpful JSON generators for both Android and iOS. 34:32 They may not be perfect, but at least it's going to save you 90, 34:36 95% of your work because it's gonna do a bunch of boilerplate stuff for you. 34:40 Then you can go in and make a few modifications. 34:43 So, for the Java example, I use this one here called jason gen. 34:45 And you pass in the URL that you're looking at, and give it a few parameters. 34:50 So give it a package name and your base object class name. 34:54 And it generates a zip file for you. 34:58 And that's pretty much what I have here. 35:00 I had all these classes generated and it worked almost perfectly out of the box. 35:02 The only thing that was missing was I headed to add, I had to add 35:07 somewhere, I had to add data for the list elements. 35:13 I forget, I forget where specifically but point 35:18 was, it saved me a whole bunch of work. 35:21 It was about five minutes of work, as opposed to however 35:22 long that would have taken to hand code all of those. 35:25 And there's a similar tools for iOS that we'll look at 35:27 in just a moment when we get to the iOS portion. 35:30 So up, before I come back here. 35:33 Sorry I'm jumping around a little bit trying to remember the rest of these tabs. 35:40 I have these laid out to show. 35:45 I don't have a specific example of the CardsLib or the ListViewAnimations. 35:46 Just in the interest of time, we're already running a little bit long. 35:51 But this is the Square Open Source page. 35:56 Again, Square has a bunch of libraries for different uses in Android and elsewhere. 35:57 But there's a lot for Android. 36:03 And there's a few IOS and then Java and JavaScript as well. 36:05 The cards library is just, here's more examples of 36:12 the different kind of card formats you can use. 36:16 So, you know, it looks like what you might 36:18 find in Google Now or in the Google Play Store. 36:19 And it's just really easy to pull in and adapt for your own collection of use. 36:21 And then, lastly, ListViewAnimations this 36:26 is this page doesn't actually have a demonstration but if you go to the Play 36:32 Store demo, there is a video that has a bunch 36:36 of examples of what the ListView can do for you. 36:39 And then, again, this is just, you know, you pull 36:42 in the ListView and adapt your data and then you 36:45 can make use of these canned animations, which look pretty 36:48 slick and would be a lot of work on your own. 36:50 Okay. 36:57 So the last thing here for Android I 36:57 wanna mention is a project called Android Bootstrap. 36:59 And this is by a developer named Donn 37:02 Felker, and it's an Android Studio project that 37:04 has a bunch of popular third party libraries 37:06 built into it already as an example project. 37:10 So you can see the list of the different things here. 37:12 And it's pretty up to date too. 37:15 This an older version had more backwards 37:17 compatible things like ActionBarSherlock or some other ones. 37:19 But things have been updated and it shows examples of how to use Fragments. 37:22 You see Retrofit is mentioned there, and GSON. 37:26 Robotium is is a good testing tool for 37:30 Android and it uses the back in, Parse.com. 37:32 I wanted to talk about Parse independently. 37:36 It's not exactly an Open Source product, but it's just so useful. 37:38 But for more information, to see an example of how 37:41 that's used, you could take a look at this app. 37:44 And it's, again it's just another example of looking at somebody 37:46 else's code to find out how you could do something better. 37:49 Okay. 37:54 So moving down to iOS we talked a lot about Gradle as a dependency manager. 37:54 And we saw how Gradle can pull in things automatically into our project. 38:00 iOS has the same thing. 38:04 It's been around longer. 38:05 It's called CocoaPods. 38:06 And this is again where I was saying that it, before CocoaPods, integrating 38:08 into an iOS project could be a real headache depending on your library. 38:13 With CocoaPods it's like Ruby Gems, if you're familiar with that concept. 38:16 It requires Ruby. 38:22 It's, it's built with Ruby. 38:23 So when you install it you know, when you install 38:24 it on your machine, you have to install it using Ruby. 38:26 And then it installs and updates third party libraries. 38:30 And one of the key differences is that when 38:33 you use CocoaPods it creates something called an Xcode workspace. 38:36 And you need to work with your project in the 38:40 framework of that Xcode workspace, instead of the Xcode project. 38:42 If that doesn't make sense, it's okay. 38:46 We're gonna look at an example here in just a second. 38:47 If you wanna get started with CocoaPods, these 38:50 are a blog post and a video of Treehouse. 38:53 They're both give a nice overview of how to get started with CocoaPods and 38:56 pull in a library to, to get familiar with, with how to do it. 39:00 It walks through the set up on how to install 39:04 CocoaPods and then set it up for your Xcode project. 39:06 Okay. 39:14 So we saw a couple different highlights of Android open source libraries. 39:14 I've got a few listed here as well for iOS. 39:19 The first one here in the upper left is called AFNetworking and it's 39:21 a very popular networking library to handle whatever kind of network you need. 39:25 You want a lot of open source tools 39:30 are built on top of AFNetworking, such as RestKit. 39:32 RestKit is the iOS version of Retrofit that we saw for consuming our Rest APIs. 39:36 And RestKit is built on top of AFNetworking. 39:42 The other two are just examples of smaller things that can be really helpful. 39:44 TPKeyboardAvoiding it, how many people have either used this or had to program on 39:48 keyboard that has elements on the screen that scroll out of the way by themselves. 39:55 Show of hands, anybody? 40:01 Okay, well if you need to, this is so much easier than 40:03 trying to do it yourself, because in iOS when you've got a 40:06 page of controls that need user input, you need to be responsible 40:10 for making sure they get out of the way of the soft keyboard. 40:15 And the Apple documentation has. 40:19 Guidelines on how you need to do 40:23 that yourself, but it involves following a certain 40:24 protocol, implementing a bunch of methods, and setting 40:27 up your scroll to be a different way. 40:29 It's a real headache. 40:30 So instead, what you do is you use this 40:31 TPKeyboardAvoiding library, you pull in a scroll, a special 40:34 scrollview that has all this code built in for 40:38 you, so then you just drop your controls in there. 40:40 And it's all handled automatically. 40:43 And it's again, one of those libraries that's very popular. 40:45 It's up-to-date, so you know you're getting a reliable quality 40:48 solution, rather than trying to do it on your own. 40:52 The SSKeychain, I'm not going to show you an example 40:55 of, but it's specifically to interact with the iOS Keychain. 40:57 It's for both iOS and Mac. 41:00 But so, it's a way to access user credentials. 41:02 So if you wanna store your user credentials in the iOS or Mac key chain. 41:05 You could reference them using this open source library. 41:10 so, okay. 41:15 Why REST kits? 41:16 Specifically, that was, remember when we looked at GitHub? 41:17 I, I said iOS REST, and RestKit was the first. 41:20 Response the first result that came up. 41:23 It's comparable to Retrofit and it just makes 41:27 for easy REST API calls, and it has that 41:29 kind of JSON to Objective-C object mapping that we 41:33 saw but it's not quite as clean as Retrofit. 41:36 Retrofit was all handled kind of under the hood by the JSON Library. 41:40 RestKit, will do the mapping for us, but we 41:45 need to be a little more explicit in our mapping. 41:47 And you'll see what I mean here in just a moment with an example. 41:49 Okay. 41:52 So, actually, pardon me. 41:53 I've got the project open, but I wanted to show where 41:59 you would differentiate between the Xcode workspace, and the Xcode project. 42:02 So if I go to 42:07 development > open source demo IOS, A regular Xcode project, when 42:10 you create a new one, gives you this Xcode project file, 42:16 When you go through the CocoaPods installation or when you rather 42:20 when you use it to add a library to your project. 42:25 The first time you do it, you're going to run 42:28 a command that will generate an Xcode workspace file instead. 42:30 And this is what you use to then open your project. 42:34 If you open the Xcode project itself, then it won't have 42:36 the necessary components from CocoaPods to pull in your third party library. 42:39 So then you just have to switch over to using the Xcode workspace after that. 42:43 So how does CocoaPods know what to include in your project? 42:49 So we saw the one line that we added in Gradle. 42:54 CocoaPods uses something called a pod file, and the format 42:56 is a little bit different but the idea is the same. 43:01 We add one line for each pod we want to include. 43:04 And they, CocoaPods will go out to repository. 43:07 And it will check and match the, the pod specs for the library one. 43:10 And it will take care of downloading the necessary components, and 43:16 adding all the additional frameworks or other pieces you might need. 43:20 And that's where it really helps because it automates that 43:23 process where you need to set flags, and include frameworks. 43:27 And make other changes to your project that are easy to mess up. 43:30 So this line here includes RestKit. 43:33 And if we go to CocoaPods' website you can search the library of available CocoaPods. 43:36 So here, if I search for RestKit specifically, I 43:43 can read up about how to include the RestKit library. 43:47 Or if I just want that line for the latest version, I can copy 43:49 that specific line here to my clip board and paste it into my pod file. 43:52 Once we have the pod file we need to go into 43:56 the command line, and do a, something called a pod install. 44:00 That's the command that generates our Xcode workspace. 44:03 And if we wanna update this, so let's say 44:07 a new version of RestKit comes out, maybe it's 0.24. 44:09 We would specify the change in our pod file, 44:13 because right now we're tied to that version 0.23. 44:16 If we update our version, we then need to run a separate command called pod update. 44:21 We need to go back and manually update our libraries. 44:24 And again, the reason that's not automatic is in 44:28 case an update would break something from your project. 44:29 It's up to you to see if you want to take the latest update and pull it in. 44:31 And it's the same thing with Gradle as well. 44:36 So let's go back to this project here and I want 44:41 to take a look at an example of how to use 44:43 RestKit, and you'll see here that it's it's a little bit 44:46 verbose compared to Retrofit which is a common complaint of Objective-C. 44:50 But with a good working example, its easy fairly easy 44:55 to extend it or change it for your own APIs. 45:00 So this is consuming the same forecast API and we see the same kind of path here with 45:07 the forecast and the parameters, the key is the 45:11 first one, latitude and longitude, and we're plugging them in. 45:13 Then we use this element to create something called a response descriptor. 45:17 I don't want to spend too much time on the inner workings of how, how to 45:25 setup a RestKit, but we see that we need to create our own mapping of the objects. 45:28 And then we set the method, the path pattern is what we saw 45:35 up here the, the API path and then the status post we're looking for. 45:39 And this is again like Retrofit, it's going to make an asynchronous call. 45:44 It's gonna have a callback mechanism in Objective-C, 45:48 it's the blocks that we see down here. 45:50 So once we have everything registered. 45:52 And I'm gonna talk about the mapping here in just a second. 45:54 We set up the request and we make it so make the call down here, operation start. 45:57 But we have to tell it what to do when we get a response from the API. 46:04 And that's where the blocks come in. 46:07 We've got a success block and a failure block. 46:09 And on success here, we're just going to parse through the 46:13 forecast and update the display and on the failure, its just login. 46:15 so, once again were going to need a object 46:22 models in Objective-C to represent that complex JSON we saw. 46:25 This was the, JSON itself here, and these are the, object models here. 46:29 This is similar to what we saw in Android. 46:39 And again, I didn't hand-code these. 46:41 These were generated by a tool. 46:43 So there's a couple different tools available. 46:45 I used specifically one called. 46:48 Where is it? 46:53 I use this one call JSON Accelerator. 46:55 It's a Mac app, you downloaded, you past in your JSON and 46:57 generate you model, and then you can copy them into your project. 47:00 There's another one that I didn't try out but looks promising. 47:04 It's called RestKit Generate, it's again from GitHub. 47:07 So, I, I looked for you know, I didn't 47:10 know what might be available to generate model's for RestKit 47:12 so I went on Google and I went on 47:16 GitHub and I looked for you know RestKit generate models. 47:17 Or generate JSON model's for RestKit. 47:21 Things like that and ended up with these two different tools. 47:23 This is our Ruby-based tool, I think, yeah and it just does the same thing. 47:26 It'll generate the model classes that we need. 47:31 And we copied them into our project and then if they're available for the mapping. 47:34 Now I saved mapping for the end because this was the cumbersome part of RestKit. 47:37 But this is, no matter what you're doing, 47:43 whether you're doing an API call on your own 47:45 or using the library, you're going to have to 47:47 map the response, the JSON response to your objects. 47:50 Go back to my code and back to the view control. 47:56 So here we map the specific JSON object 48:01 names to the properties of the objects. 48:07 And it does like a one to one mapping. 48:13 We, there are different ways you can map it. 48:16 But this because I'm using the same names in the JSON as 48:17 the object models, we just need to specify where they are coming from. 48:20 And then with this is in place 48:25 [COUGH] we also need to establish parent-child relationships. 48:26 Or nested objects as well. 48:31 So, for example, a forecast object includes an alerts object. 48:34 And down here at the bottom, we add those relationships. 48:39 So, forecast mapping has the forecast object has an hourly object. 48:43 It has a daily object. 48:47 And this allows RestKit to go through and make sure 48:49 that everything gets parsed correctly into the objects we need. 48:51 Once that's in place, then we just call the method like this, and the blocks, oh 48:57 yeah, and the blocks, for the response we 49:05 define down there, this code is a little cluttered. 49:07 I apologize, it's not very organized. 49:09 But the blocks for success and failure will then handle the response for us. 49:11 okay, we talked about the RestKit model specifically, already. 49:16 Got a few minutes to go, which leaves me 49:23 a minute here to talk about CocoaPods and Swift. 49:27 Does, everybody familiar with, when I, I 49:33 keep talking about Swift, assuming everybody knows what 49:35 it is but, a show of hands if you do know what Swift programming language is. 49:37 Okay, so most people. 49:41 This is the future of iOS development. 49:43 Apple has been working Swift for a couple of years and they announced it at WWDC a 49:46 couple weeks ago and it won't, the language itself is available to 49:51 talk about and look at but you need to have Xcode 6 beta to work 49:58 with it, and to get Xcode 6 beta, you need to be an Apple developer. 50:03 So that's a long way of saying you need to 50:06 be in the Apple developer program to really play around Swift. 50:07 But we can talk about it and we can look at 50:11 some examples but one of the first questions of course was, 50:12 if I'm doing a Swift project, can I use CocoaPods, can 50:17 I use an existing library, and can I use a Swift library? 50:20 And the answer to both questions is yes. 50:25 So it's a definitive yes for the first if you wanna 50:27 use an Objective-C library, such as RestKit in a Swift project. 50:33 You need to do something called, use a bridging header. 50:37 And that's a bridge from Swift to Objective-C. 50:40 And I just included an example. 50:43 There's a couple different articles on how to do that, 50:45 but you basically set the header file that tells the 50:47 Objective-C components you need and it puts them in place 50:50 so that you're Swift project knows how to find them. 50:53 Because if you try to import an Objective-C file 50:56 into Swift you're going to get a compiler error. 50:59 And then sepo, specifically, to use CocoaPods to include a Swift 51:03 project, a Swift open source project into your own Swift app. 51:06 That is supposedly in the works. 51:10 I haven't checked the very latest information to 51:12 see if, you know, where, where that is. 51:15 But that should, supposedly be done in time for when Swift is publicly available. 51:17 >> If you're bridging to an Objective-C library in Swift, would you need to, how 51:23 you you use the Objective-C library in Swift, 51:28 how would the, how would the syntax call? 51:31 >> Yeah, so, from what I understand, let's, 51:34 they give an example here in this article. 51:36 So then once you pull it in, this, this just walks through how to set it up. 51:40 so, you're ready to use Objective-C in your project. 51:44 And this is SVProgress HUD so- 51:51 [BLANK_AUDIO] 51:58 I'm not exactly sure how the call is made it. 52:03 >> Yeah, that was what I was trying to figure out. 52:07 >> Yeah, because it's the, this is the Swift method format, but- 52:09 >> If you write Swift and know stuff is translated 52:13 across the bridge, or you have to put it in Objective-C? 52:16 >> Yeah, I'm not sure. 52:20 I haven't tried this out myself yet. 52:20 Good question, though. 52:23 [BLANK_AUDIO] 52:23 It's a good segue because we're on to final questions. 52:26 That's all I had specific to cover. 52:30 But if you have any questions now please ask. 52:33 If you think of anything afterwards find me 52:36 on Twitter and, and follow up there as well. 52:38 Any other questions while we're in here? 52:41 No? 52:45 Cool. 52:45 All right thank you so much for listening I've got two free shirts if anybody wants. 52:45 There's a small and a large just come up and, and ask me. 52:50 And first come, first serve, you're welcome to them. 52:53 Once again that stuff from Treehouse is in the back 52:55 if you want to give us a look check out teamtreehouse.com. 52:58 There's cards for a free trial, and stickers and things and there's, we have 53:01 more information about both Android and iOS, 53:04 CocoaPods and Gradle and, good stuff like that. 53:06 All right. 53:11 Thanks a lot. 53:11 [APPLAUSE] 53:12