Running the App3:08 with Ben Deitch
In this video we'll take a look at the app and see how it works!
Now that we've got the app, let's talk about what this app is. 0:00 Welcome to PizzaKeeper, the only app that lets you create and 0:04 name your favorite pizzas. 0:08 In the main activity, we'll show a list of created pizzas, 0:10 with the last item on the list being the option to create a new pizza. 0:14 We don't have any pizzas yet. 0:18 But when an item on this list is clicked, 0:20 we'll start a new activity to let users customize their pizza. 0:23 If they clicked an existing pizza, we'll show that pizza. 0:27 And if they clicked the new pizza button, they'll start with a blank canvas. 0:30 Right now, the app doesn't do very much. 0:35 We can change the name of the pizza And 0:38 click on toppings, But that's about it. 0:43 The save and delete buttons just show toasts and 0:47 take us back to the main activity. 0:51 And if we rotate the screen, we can see that our changes aren't being saved. 0:53 There's clearly some work to do with data persistence. 0:58 But first, let's take a look at the code and 1:02 get comfortable with how it all comes together to create the app. 1:04 Starting from the top, we have the data package. 1:11 This is where we'll be keeping all of our files that have to do with data 1:15 persistance. 1:18 Right now, it just contains two classes. 1:20 One defining a Pizza object, and one defining a Topping object. 1:23 Since our goal is to put this data into the database, each of the objects 1:27 contains an id which can be used to uniquely identify the object. 1:32 In addition to the id, a Pizza will require a name and 1:39 the date it was created. 1:43 As for a Topping it will be represented by an id, a name and 1:45 the name of the drawable we should use to represent the topping. 1:50 Moving on the App file, at the top of this file we define a topping's list, 1:55 which contains a toppings objects. 2:00 Remember, that in Kotlin, when a variable is declared outside the scope of a class, 2:03 it's available from anywhere in the app. 2:08 So this toppings variable will be available wherever we need it. 2:11 Above the toppings variable, we declare a mapping of toppings to bBtmaps, 2:16 called toppingBitmaps. 2:21 When the application is first created, 2:24 we'll populate toppingBitmaps with the Bitmap for each topping. 2:26 This way, instead of storing entire Bitmaps in our database, 2:32 we'll just store the name of the drawable and 2:37 turn it into a Bitmap when the application is first created. 2:39 Also, just to be clear, this application onCreate method will be 2:44 called before anything happens with activities. 2:48 So by the time we're in main activity, 2:52 toppingBitmaps will be filled with Toppings and Bitmaps. 2:55 All right, that covers the first bit of code. 3:00 Coming up next, we'll look at the rest of the code and 3:02 start planning how to introduce data persistence. 3:05
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