DetailsFragmentBackgroundController

Kotlin |Java

open class DetailsFragmentBackgroundController

kotlin.Any
↳	androidx.leanback.app.DetailsFragmentBackgroundController

Controller for DetailsFragment parallax background and embedded video play.

The parallax background drawable is made of two parts: cover drawable (by default FitWidthBitmapDrawable) above the details overview row and bottom drawable (by default ColorDrawable) below the details overview row. While vertically scrolling rows, the size of cover drawable and bottom drawable will be updated and the cover drawable will by default perform a parallax shift using FitWidthBitmapDrawable#PROPERTY_VERTICAL_OFFSET.

***************************
         *      Cover Drawable     *
         * (FitWidthBitmapDrawable)*
         *                         *
         ***************************
         *    DetailsOverviewRow   *
         *                         *
         ***************************
         *     Bottom Drawable     *
         *      (ColorDrawable)    *
         *         Related         *
         *         Content         *
         ***************************

Both parallax background drawable and embedded video play are optional. App must call enableParallax() and/or setupVideoPlayback(PlaybackGlue) explicitly. The PlaybackGlue is automatically PlaybackGlue#play() when fragment starts and PlaybackGlue#pause() when fragment stops. When video is ready to play, cover drawable will be faded out. Example:

DetailsFragmentBackgroundController mController = new DetailsFragmentBackgroundController(this);
 
  public void onCreate(Bundle savedInstance) {
      super.onCreate(savedInstance);
      MediaPlayerGlue player = new MediaPlayerGlue(..);
      player.setUrl(...);
      mController.enableParallax();
      mController.setupVideoPlayback(player);
  }
 
  static class MyLoadBitmapTask extends ... {
      WeakReference<myfragment>
  mFragmentRef;
      MyLoadBitmapTask(MyFragment fragment) {
          mFragmentRef = new WeakReference(fragment);
      }
      protected void onPostExecute(Bitmap bitmap) {
          MyFragment fragment = mFragmentRef.get();
          if (fragment != null) {
              fragment.mController.setCoverBitmap(bitmap);
          }
      }
  }
 
  public void onStart() {
      new MyLoadBitmapTask(this).execute(url);
  }
 
  public void onStop() {
      mController.setCoverBitmap(null);
  }
  
</myfragment>

To customize cover drawable and/or bottom drawable, app should call enableParallax(Drawable, Drawable, ParallaxTarget.PropertyValuesHolderTarget). If app supplies a custom cover Drawable, it should not call setCoverBitmap(Bitmap). If app supplies a custom bottom Drawable, it should not call setSolidColor(int).

To customize playback fragment, app should override onCreateVideoFragment() and onCreateGlueHost().

Summary

Public constructors
`<init>(fragment: DetailsFragment!)` Creates a DetailsFragmentBackgroundController for a DetailsFragment.

Public methods
open Boolean	`canNavigateToVideoFragment()` Precondition allows user navigate to video fragment using DPAD.
open Unit	`enableParallax()` Enables default parallax background using a `FitWidthBitmapDrawable` as cover drawable and `ColorDrawable` as bottom drawable.
open Unit	`enableParallax(@NonNull coverDrawable: Drawable, @NonNull bottomDrawable: Drawable, @Nullable coverDrawableParallaxTarget: ParallaxTarget.PropertyValuesHolderTarget?)` Enables parallax background using a custom cover drawable at top and a custom bottom drawable.
Fragment!	`findOrCreateVideoFragment()` Adds or gets fragment for rendering video in DetailsFragment.
Drawable!	`getBottomDrawable()` Returns the drawable at bottom.
Bitmap!	`getCoverBitmap()` Returns Bitmap set by `setCoverBitmap(Bitmap)`.
Drawable!	`getCoverDrawable()` Returns the cover drawable at top.
Int	`getParallaxDrawableMaxOffset()` Returns Default parallax offset in pixels for bitmap moving vertically.
PlaybackGlue!	`getPlaybackGlue()` Returns current PlaybackGlue or null if not set or cleared.
Int	`getSolidColor()` Returns color set by `setSolidColor(int)`.
open PlaybackGlueHost!	`onCreateGlueHost()` Creates a PlaybackGlueHost to host PlaybackGlue.
open Fragment!	`onCreateVideoFragment()` Creates a Fragment to host `PlaybackGlue`.
Unit	`setCoverBitmap(bitmap: Bitmap!)` Convenient method to set Bitmap in cover drawable.
Unit	`setParallaxDrawableMaxOffset(offset: Int)` Sets default parallax offset in pixels for bitmap moving vertically.
Unit	`setSolidColor(@ColorInt color: Int)` Convenient method to set color in bottom drawable.
open Unit	`setupVideoPlayback(@NonNull playbackGlue: PlaybackGlue)` Enable video playback and set proper `PlaybackGlueHost`.
Unit	`switchToRows()` Switch to rows fragment.
Unit	`switchToVideo()` Switch to video fragment, note that this method is not affected by result of `canNavigateToVideoFragment()`.

Public constructors

<init>

DetailsFragmentBackgroundController(fragment: DetailsFragment!)

Creates a DetailsFragmentBackgroundController for a DetailsFragment. Note that each DetailsFragment can only associate with one DetailsFragmentBackgroundController.

Parameters
`fragment`	DetailsFragment!: The DetailsFragment to control background and embedded video playing.

Exceptions
`IllegalStateException`	If fragment was already associated with another controller.

Public methods

canNavigateToVideoFragment

open fun canNavigateToVideoFragment(): Boolean

Precondition allows user navigate to video fragment using DPAD. Default implementation returns true if PlaybackGlue is not null. Subclass may override, e.g. only allow navigation when PlaybackGlue#isPrepared() is true. Note this method does not block app calls switchToVideo.

Return
`Boolean`	True allow to navigate to video fragment.

enableParallax

open fun enableParallax(): Unit

Enables default parallax background using a FitWidthBitmapDrawable as cover drawable and ColorDrawable as bottom drawable. A vertical parallax movement will be applied to the FitWidthBitmapDrawable. App may use setSolidColor(int) and setCoverBitmap(Bitmap) to change the content of bottom drawable and cover drawable. This method must be called before setupVideoPlayback(PlaybackGlue).

Exceptions
`IllegalStateException`	If