What you're building

The [YOUR PROJECT NAME] tutorial demonstrates how [CHANGE THIS TO FIT YOUR APP...] you can control the size of a video playing in an app by using the Video Player component's Width, Height, and FullScreen features. The VideoWall uses media assets (videos stored in the app itself), but you can use the app to display videos from the internet as well.

This tutorial assumes you are familiar with the basics of App Inventor-- using the Component Designer to build a user interface, and using the Blocks Editor to specify the app's behavior. If you are not familiar with the basics, try stepping through some of the basic tutorials before continuing.

Getting Started

Connect to the App Inventor web site and start a new project. Name the new project [YOUR PROJECT NAME] and set the screen's Orientation to Landscape.

Download the following image/video files for use later on:

• BigBuckBunny (bigbuckbunny.3gp)
• NASA (nasa.3gp)
• Sintel (sintel.3gp)

Introduction

The finished VideoWall app will display a wall of three videos that can be expanded to their true size and then shrunk back down again. The app will also allow you to display the videos in fullscreen. This tutorial assumes you have followed earlier tutorials to learn how the following blocks work:

• Variables
• Procedures
• Button.Click blocks
• Logic (if-else) blocks

This tutorial introduces the following:

• Using Advanced blocks
• Resizing the VideoPlayer
• Showing the VideoPlayer video in fullscreen mode

Set up the Components

Use the component designer to create the interface for the [YOUR APP NAME]. When completed, the designer should look similar to the snapshot below.

Descriptive text should go between paragraph tags like this.

Set the properties as described below:

Add Behaviors to the Components

The interface is complete, but the buttons don't resize the videos yet. Open the Blocks Editor to add the behavior to the buttons. First, you'll define three variable blocks to keep track of the size of the VideoPlayers:

The three variables should like this:

Create the resizeVideoPlayer Procedure block. There are three VideoPlayers in the app, but you'll use one Procedure block to resize all three. To accomplish this simplicity, you will use the Advance blocks component Any VideoPlayer blocks. Create the resizeVideoPlayer Procedure block using the following blocks:

The resizeVideoPlayer block should look like the following:

The resizeVideoPlayer block will be explained later after you create the blocks for responding to button clicks.

Create the Click Blocks

The blocks you will create respond to clicks on the ResizeButton buttons. To build the three blocks, you will need the following blocks:

The blocks should look like the following:

Most blocks in App Inventor require you to know exactly what component your app will manipulate when you design the app. For some apps, you will have several of the same type of component and you want to program the same behavior for all of the similar components (like the VideoPlayer blocks in this app). The blocks in the Advanced section allow you to build some general manipulation on some type of component. When you built the resizeVideoPlayer procedure block, you didn't know specifically which VideoPlayer would be used in the procedure. The resizeVideoPlayer works on VideoPlayers; but not until the resizeVideoPlayer block is used in the ResizeButton1.Click block (for example) is the specific VideoPlayer known.

How the Blocks Work

Setting the Width and Height property for a VideoPlayer works exactly the same way as setting the Width and Height of a Button. For whatever positive number is set, the video playing will resize its appearance to fit that value. There are two values that are exceptions to the using positive values rule: -1 and -2. Setting VideoPlayer.Width or VideoPlayer.Height to -1 is like setting the Width or Height to Fill parent in the designer. Setting VideoPlayer.Width or VideoPlayer.Height to -2 is like setting the Width or Height to Automatic in the designer.

Warning: You can set the VideoPlayer Width and Height to any positive number you want. The VideoPlayer will change its size to match the values you set; but on some devices, the VideoPlayer does not change its size correctly. The behavior on such devices is usually unpredictable.

Test this behavior. Click on the Grow button below the BigBuckBunny video. The video's size should expand, and the text of the button should change to "Shrink". Click on the Shrink button below the BigBuckBunny video. The video's size should shrink back to its original size and the text should change back to "Grow".

Create the blocks for showing fullscreen video

You will now add the blocks for showing the videos in fullscreen mode. Use the following blocks:

The blocks should look like the following:

How the Blocks Work

The VideoPlayer.FullScreen block takes a true/false value (also called a boolean) to tell it whether to go full screen or not. Setting a VideoPlayer.FullScreen block to true causes that VideoPlayer to be displayed in fullscreen mode. If there is another VideoPlayer in fullscreen mode, that VideoPlayer's .FullScreen value is set to false and it is replaced with the current VideoPlayer. If a VideoPlayer.FullScreen is true, setting a VideoPlayer.FullScreen block to false causes the fullscreen mode to be exited and the app's interface to display. Test this behavior. Start playing the BigBuckVideo, and click on the Show FullScreen button below the BigBuckBunny video. The app's interface should disappear and some media controls with the BigBuckBunny video should appear. Use the Back button on your device or the emulator to exit fullscreen. The app's interface should appear.

Final Program

VideoWall Final Version

Package the final version of the app by choosing Package For Phone | Barcode from the Component Designer menu. When the barcode appears, use the barcode scanner on your phone to download and install the app.

Variations

Now that you have finished the first VideoWall app, you might want to build some variations. For example:

• Get more video files and add a second row to create a real VideoWall
• Use videos from an online server.
• Expand the resizeVideoPlayer procedure to resize VideoPlayers by small increments to create an animation effect. You could use multiple Clocks to start the resizeVideoPlayer procedure and animate multiple VideoPlayers at once.

If you distribute your app to others, make sure you respect any license requirements for the videos you use.

Below are the attributions to the video files included in this demo app. The creators of the source videos that these clips are from do not endorse App Inventor.