Dynamic Count Changes in Android's ViewPager

Android's ViewPager determines the number of pages when viewPager.setAdapter(pagerAdapter)is called, and then it doesn't update that count even when pagerAdapter.notifyDataSetChanged() is called.

So if the number count of the pages in the adapter is dynamic, you need to run this code every time the number of pages changes:

	void updatePageCount(ViewPager viewPager) {
	int currentItem = pager.getCurrentItem();
	pager.setAdapter(pager.getAdapter());
	pager.setCurrentItem(currentItem);
	}

view raw sample.java hosted with ❤ by GitHub

Using Android's TextureView to Display Video Mirrored

Android's VideoView can only play videos straight and not mirrored.
If you want your app to play a video mirrored (for instance if the video was recorded using a front camera), you will need to use a TextureView, which can be easily mirrored by specifying android:scaleX=-1 in the XML file, or textureView.setScaleX(-1) in the code.

Here is a code sample for playing video using TextureView, with the option of displaying the video mirrored:

	public class SampleActivity implements SurfaceTextureListener {
	boolean isMirrored = true;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
	super.onCreate(savedInstanceState);
	setContentView(R.layout.activity_sample);
	TextureView textureView = (TextureView)findViewById(R.id.myTextureView);
	textureView.setSurfaceTextureListener(this);
	textureView.setScaleX(isMirrored ? -1 : 1);
	}
	@Override
	public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
	MediaPlayer mediaPlayer = new MediaPlayer();
	mediaPlayer.setSurface(new Surface(surface));
	try {
	mediaPlayer.setDataSource("my_video_file.mp4");
	mediaPlayer.prepare();
	mediaPlayer.start();
	} catch (Exception e) {
	e.printStackTrace();
	}
	}
	@Override
	public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {return false;}
	@Override
	public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int width, int height) {}
	@Override
	public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {}
	}

view raw sample.java hosted with ❤ by GitHub