Testing for Interfaces

One of the things that makes interfaces most useful 0:00 is that you can apply them to many different classes. 0:03 Those classes may not have anything else in common besides the one interface and 0:07 that's fine. 0:12 The same interface can be applied to a collection class or a single object class. 0:13 The savory flavor interface that I explained in the first video 0:18 could be applied to a fruit or a vegetable. 0:22 It could even be applied to meat or grain. 0:25 The ability to check for specific interfaces allows us to use those methods 0:29 on any object that matches the interface. 0:34 This will allow our views to adapt to the content type 0:37 that they're currently displaying. 0:40 Let's check for our trackable and shareable interfaces and 0:43 display the details. 0:46 Let's start out in our list view. 0:48 After the title, let's add a conditional statement, 0:50 to check if content is an instanceof TrackableInterface. 0:56 Instance of works for classes, inherited classes, interfaces and 1:09 extended interfaces. 1:13 If it matches the interface, 1:16 we can include the track.php file from the current directory. 1:17 I've supplied the structure for 1:29 the track file but we're going to need to add the tracking methods. 1:30 Echo content getAuthor. 1:41 Echo content getDateTime. 1:50 Now we can close track.php. 1:55 This is all I want for the list view but 1:57 let's copy the conditional from the list view to use it on a single item view. 2:00 Let's duplicate this conditional for the ShareableInterface. 2:13 For the ShareableInterface, we'll include the share file instead. 2:22 Just like with the track file, I've supplied the structure. 2:27 We just need to go in and add the methods. 2:31 ShareTwitter, echo content, shareFacebook. 2:44 And finally, echo content, 2:56 shareEmail. 3:03 Now we can close this file. 3:06 One last thing before we preview these changes. 3:08 On this single page I want to wrap both these includes in a div. 3:11 echo div class=row. 3:14 Then we'll close our div. 3:27 Now let's preview these new changes on our site. 3:31 The list view page now displays the user, date, and time for each post. 3:35 When you click on an individual page post, along with the user, date, and 3:42 time, we also see the links for sharing on Twitter, Facebook, and by email. 3:47 Now, that's you've worked with interfaces, you're ready to explore abstract classes 3:54 in the similarities and differences they bring. 3:59