One of the cool trend on mobile UI I’ve seen a lot is using video as View background. You can see it on some big mobile app products like Tumblr, Spotify, and Vine. As you can see, they have this cool Home View with sign in and sing up button with video playing in background. This feature is so cool and can make your app look more professional. This time, I’ll show you how to implement it in Xamarin.Forms app. All we need is to implement two custom renderers for Android and iOS each.
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Creating Video View Control for Xamarin.Forms
Let’s create a new Xamarin.Forms PCL project first and name it
BackgroundVideo. Now let’s head to the PCL library and create a new class called
Video inherited from
For the sake of the tutorial, we’re going to make this control with simple requirements.
We need a bindable property to point which video to be displayed. I’m going to call it
Source property. It’s a string to locate which video file to be played. On iOS,
Source property is relative to
Resources directory as for Android, it is relative to
Next thing we need is a boolean to define if we want the video in loop or not. Let’s call this property
Loop. By default, I set this value as
true so when you set a video
Source property, it would be looped by default.
Finally, we’re going to need a callback fired when video is finished. For simplicity, I use
Action class called
OnFinishedPlaying. You can modify it to event or anything you comfortable with.
After we created this class, next thing to do is to implement custom renderers for both iOS and Android.
Video View Control iOS Custom Renderer
First thing to do is to create a custom renderer class called
VideoRenderer inherited from
ViewRenderer<Video, UIView>. The idea is to use iOS native video player with the help of
MPMoviePlayerController class and set its native control to our
Video custom view. Also we’re going to need an
NSObject to listen the event from video player wether it is ended or not.
To start iOS video player, we need to check wether the video from
Source property exists in Resources budnle or not. If it doesn’t exist, we’ll display an empty view.
If the video file exists, we need to create
MPMoviePlayerController and parse the location of the video file as
NSUrl. To make our custom control clear, without border or anything, we need to set
MPMovieControlStyle.None and background color to
Also, we probably will have one video file for any resolution. You don’t want it to look stretched on some device, right? To make the video resolution looks consistent, we need to set video player
We also have this
Loop property to define wether the video playing will be looped or not. To set it to loop, we need to change video player
MPMovieRepeatMode.One. Otherwise, set it to
Finally, to make video player play the file, we call
PrepareToPlay() function. To display the video to our custom control, we need to use
The rest of the code is to override
OnElementPropertyChanged function so it can be functionally working from Xamarin.Forms project. Under
OnElementChanged, we need to listen to video player playback finish event and invoke
OnFinishedPlaying action. The following snippet is the simplest code necessary to make it work.
Now that iOS implementation is completed, let’s head to our Android project.
Video View Custom Renderer for Android
Create a new custom renderer on Android project and let’s name it
VideoRenderer, too. We’ll inherit this renderer with
ViewRenderer<Video, FrameLayout>, meaning it will be displayed as
FrameLayout in native Android control.
One thing that made Android implementation a bit complicated is that we need two kind of views if you want to cover old Android versions. If you just want to cover modern Android OS from Ice Cream Sandwich or more, you can just focus on
TextureView implementation, if not you’ll also need to implement it using
Please note that
VideoView implementation here is not optimal. Maybe you’ll notice some flickering. That’s why I add view called
_placeholder. This is just an empty view. It’ll be displayed when no video playing or when in video source changed transition. If the video file ready to play and display,
_placeholder will be hidden.
Now before we thing about what video container to use, we need to implement the video player itself. Android already provide us with their
MediaPlayer class. We’ll need to use this object and make sure it only created once. We can reuse the same object if we change the video source.
We need to set
Completion event to implement our
OnFinishedPlaying callback. We also need to set
Looping property to our custom
There is one thing that different from our iOS implementation, there is no easy property set to display video resolution as aspect fill! That means we need to implement our own method into custom function called
AdjustTextureViewAspect(). This function will be called on
VideoSizeChanged callback. We’ll talk about this implementation later.
Now that we have our video player object, next thing is to create function that play video from
Source property. Please remember that video file on Android need to be stored under
Assets directory. We can open this file by using
If the file doesn’t exist, it’ll throw
Java.IO.IOException. That means we don’t need to display anything on our video container.
If the file exists, we just need to reset our video player, then set data source based on previous step. We can’t just play the video directly, so we need to prepare it first. When preparation complete, it’ll trigger
Prepared event and display the video to one of our implemented video view from previous step.
As previously mentioned, Android doesn’t provide us easy property to scale our video to aspect fill. You know it yourself that Android devices have so many screen resolution so keep the video like it is is not an option. We need to scale it properly so it won’t look stretched.
Good news is, we can do that if we use
TextureView. Bad news is for now I don’t know how to implement it with
VideoView. But it’s better than nothing right?
The idea to make video scale properly is to use matrix to scale the content of
TextureView. It is scaled up or down based on video size and view size. Then, after it’s scaled, it is positioned at the center of the view.
As mentioned earlier, if we want to support a wide range of Android OS, we need to implement it into
VideoView. This will be implemented under
OnElementChanged function. Both implementation have some same properties. We will make their Background color to transparent and layout parameters to match parent. This way it won’t have any color to display when there is no video, and it’ll fill entire container.
Following snippet is how to implement it on our Video custom renderer. You see it’s similar with our iOS implementation, except for container creation and video playing.
Since we’re using
VideoView, there is some function from interfaces need to be implemented. One of them is to remove video when texture or surface is destroyed. To do that, we’re going to need to set
_placeholder visibility to visible.
TextureView, we need to implement
TextureView.ISurfaceTextureListener interface. We set video player’s surface when texture available and hide it when texture destroyed. Following snippet shows you how to implement it.
VideoView, we need to implement
ISurfaceHolderCallback interface. Similar with
TextureView, we set video player’s display when surface created and hide it when surface destroyed. The complete implementation of this interface can be see on following snippet.
That’s all we need for Android. Now that we all have everything needed, we can test this control to Xamarin.Forms Page.
Testing to Xamarin.Forms Page
Before we create a test page, I recommend you to prepare your own video file. It is recommended as vertical video so a lot of space won’t be wasted.
But, if you don’t have any video to test, don’t worry. You can download free videos to use from Coverr. They don’t have any vertical videos, we can still use it. You can either crop it into vertical video or you can just use it as it is since we already handle scaling to aspect fill on our code.
So use any video you like. I recommend any file as long as it’s mp4 video with h264 encoding. In this tutorial, I use video from Coverr called Orchestra. You can download it from here.
For some Android and iOS devices, especially the old products, they probably can’t play some mp4 files. This is mostly caused by not-supported baseline profile. To fix that, you can re-encode the video using a tool like
ffmpegand change its baseline profile based on your preferences. See following table to check baseline profile compatibility with iOS. See Supported Media Formats from official Android guide, too.
|Baseline||3.0||All devices||-profile:v baseline -level 3.0|
|Baseline||3.1||iPhone 3G and later, iPod touch 2nd generation and later||-profile:v baseline -level 3.1|
|Main||3.1||iPad (all versions), Apple TV 2 and later, iPhone 4 and later||-profile:v main -level 3.1|
|Main||4.0||Apple TV 3 and later, iPad 2 and later, iPhone 4s and later||-profile:v main -level 4.0|
|High||4.0||Apple TV 3 and later, iPad 2 and later, iPhone 4s and later||-profile:v high -level 4.0|
|High||4.1||iPad 2 and later, iPhone 4s and later, iPhone 5c and later||-profile:v high -level 4.1|
|High||4.2||iPad Air and later, iPhone 5s and later||-profile:v high -level 4.2|
After you get your video file, place it to the folders for each OS. On Android, you should put it under
Assets directory. On iOS, you should put it under
Resources directory. For this tutorial I put the file under
Assets/Videos on Android and
Resources/Videos on iOS.
Once you put them all to correct folder, we need to create our Page on Xamarin.Forms PCL project.
This is a simple page with smallest components. We’ll create a Home Page, with video background, two text boxes for username and password, and to buttons for sign in and sign up. There is no logic in this page, I just want to show you how to make a beautiful home page.
For better controls placement, I use Grid as container. See following snippet for the complete XAML.
That’s it. If you don’t want the video to be looped, just change its
Loop property. If you want to do something when video ended, just set
OnFinishedPlaying from C# code. Now let’s see how it runs.
See it in Action
If you set everything correctly, The following figure is how it run on iOS device or emulator. As you can see, there are two text boxes and two buttons. The video is playing as the page background smoothly.
Similar with iOS version, the following animated gif image shows how it looks on Android device or emulator. See that text box style difference from iOS version. But let’s care about it later, the point is video background consistently work just like iOS.
All you need to do the rest is to make styling more consistent through any platforms.
Once again, all I can say is you can make any cross platform control you want by using Custom Renderer. As long as you understand how to code in native language (well, you can Google it though), you can create anything.
As for performance, I believe I said it earlier, you probably see some flickering on old Android devices. For now I don’t have any idea to optimize it.
If you have any idea and suggestion, feel free to leave a comment below.
You can download completed project on GitHub.
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