WEBVTT 00:01.360 --> 00:07.420 Now, in the previous lecture, we created an Android virtual device to run and simulate an application. 00:08.300 --> 00:13.700 So you know what that means, we are now ready to develop a basic quiz game map. 00:15.240 --> 00:21.540 This will, of course, help you better understand the structure of a mobile app, but it will also 00:21.540 --> 00:25.740 teach you the different components of Android apps in general. 00:27.650 --> 00:28.370 So let's start. 00:29.290 --> 00:34.090 Go to Android studio, start a new Android project. 00:37.390 --> 00:42.110 Now, of course, there are different types of activities for phones and tablets. 00:42.850 --> 00:45.880 Well, just select an empty activity and click next. 00:48.030 --> 00:49.980 Now, what to call the application. 00:52.320 --> 00:54.750 And I'll develop it with Java. 00:56.720 --> 01:03.680 Now, you can, of course, select the SDK here for whatever Android version that you want to use. 01:05.110 --> 01:11.800 Now, before selecting it, just be sure that you've downloaded it and it is available on your computer. 01:12.850 --> 01:13.110 All right. 01:13.120 --> 01:16.240 So let's look at the SDK manager before creating a project. 01:17.750 --> 01:20.410 Click on Configure on the bottom right corner. 01:22.080 --> 01:27.630 Select the lowest version of Android, your app will support in the minimum SDK field. 01:28.780 --> 01:34.510 Now, before using any Android version, we should install its SDK platform package. 01:36.440 --> 01:46.960 So I have SDK packages for Android nine with twenty eight API level and Android 10 are with 30 API levels. 01:48.290 --> 01:53.380 So as I said before, we can use one of the Android versions, eight, nine or 10 throughout the course, 01:53.390 --> 02:00.500 so why don't we just go ahead and install Android 10 queue version with 29 API levels? 02:01.530 --> 02:04.470 And I can select the checkbox and click, OK? 02:06.510 --> 02:10.070 And I mean, these components will be installed, OK? 02:11.880 --> 02:14.280 And you got to wait for a little bit. 02:18.250 --> 02:19.670 All right, so finish. 02:21.010 --> 02:25.300 So now we have the SDK package for Android version 10 Q. 02:26.800 --> 02:30.460 And we can go back and continue where we left off. 02:32.500 --> 02:35.710 So I selected the minimum SDK for the project. 02:36.780 --> 02:38.040 And finish. 02:39.860 --> 02:45.980 And bump, bam, just like that Android studio main window opens. 02:47.640 --> 02:52.050 Now, you may remember that we examined the file structure of an application before. 02:53.230 --> 03:01.150 Now, if this is the main activity, it's the entry point for your app, so when you build and run your 03:01.150 --> 03:07.090 app, the system launches an instance of this activity and loads its layout. 03:09.650 --> 03:15.260 So under the red folder, there's an Excel file defining the layout for the activities user interface. 03:16.830 --> 03:19.170 Let's first create a user interface. 03:21.880 --> 03:27.800 So this is the default layout and TextView with a split view in the upper right corner. 03:27.820 --> 03:30.520 We can edit the user interface on the XML file. 03:33.950 --> 03:43.280 Now, change the layout to relative layout, and it is a view group that displays child views in relative 03:43.280 --> 03:44.060 positions. 03:45.160 --> 03:51.760 So we'll delete the default TextView, I'm going to add buttons and text fields in the design section. 03:53.780 --> 03:59.840 So first of all, add a button and add an attribute to a line at the bottom. 04:02.810 --> 04:03.920 And I'll click true. 04:05.650 --> 04:11.770 So I want to change the size of the button and create four buttons just like this so I can copy and 04:11.770 --> 04:14.380 paste to create the same buttons. 04:16.620 --> 04:18.600 Now add to Texas. 04:19.580 --> 04:22.370 One for the score, one for the questions. 04:24.240 --> 04:29.100 I'll also add an attribute for this to a line at the top. 04:30.210 --> 04:31.440 And quick to. 04:33.580 --> 04:35.350 I'll add another TextField. 04:37.050 --> 04:39.870 Now we're going to need a larger area for questions. 04:41.240 --> 04:46.490 So let's say I add an attribute layout a parent top. 04:48.050 --> 04:52.250 I'll center this horizontally, but let's change it on the XML side. 04:56.360 --> 04:58.490 So this is the text for you that I want to change. 04:59.550 --> 05:02.070 This is how I add an attribute in the code. 05:07.140 --> 05:13.230 Now it's in the center, so let's add a margin to left for this TextView. 05:19.730 --> 05:21.220 All right, that's a little better now. 05:24.060 --> 05:28.260 So we can now give some names for these buttons and text views. 05:32.370 --> 05:34.640 Buttons will be the answers. 05:48.430 --> 05:52.300 All right, so now we can create functions in the main activity file. 05:55.590 --> 05:57.240 First, define buttons. 06:00.550 --> 06:03.250 So we need to import four button. 06:07.230 --> 06:12.030 And define text views as score and questions. 06:14.550 --> 06:18.050 Now we'll create the activities in the uncreate method. 06:19.450 --> 06:26.200 So when an activity first calls or launches, then the uncreate method is responsible for creating the 06:26.200 --> 06:26.770 activity. 06:30.940 --> 06:36.460 Now, here's the fine view by IED method, and it'll return a few object. 06:37.910 --> 06:41.780 In fact, we call all the objects using this method. 06:48.800 --> 06:50.870 And these objects should be TextView. 06:54.090 --> 07:01.320 Now, to specify an action when the button is pressed, will set a click listener on the button objects 07:01.800 --> 07:04.230 with the set on Click Listener Method. 07:05.810 --> 07:12.020 So if you press enter while you create a new listener, Android studio will autocomplete the rest of 07:12.020 --> 07:12.590 the function. 07:15.490 --> 07:19.900 So now we can create this method for all buttons, all the answer buttons. 07:23.950 --> 07:30.520 Now, before completing these methods, let's let's first create a new Java class for the questions. 07:32.200 --> 07:35.770 So, right, click on the project and create Java class. 07:41.030 --> 07:43.730 Now, let's define a string array that will. 07:44.650 --> 07:45.910 Keep the questions. 07:47.540 --> 07:48.050 And. 07:49.270 --> 07:52.220 I'll create some questions about Android versions. 07:52.240 --> 07:52.900 What do you think? 07:56.400 --> 07:59.070 Next, I'll create another array for the choices. 08:08.330 --> 08:13.480 And I'll mix the order of the choices for each different question. 08:15.750 --> 08:20.110 And create the last array that will keep the correct answers in order. 08:23.810 --> 08:28.480 I recall both questions and answers will need to create methods that will return them. 08:40.920 --> 08:43.800 So I'll create them for all answers and choices. 08:50.860 --> 08:56.440 So as you can see here, we created a two dimensional array for choices to match questions and answers. 08:57.630 --> 09:03.840 I'm not going to really dive too deeply into this topic because it's not really our subject now.