File	Doc	Category	Size	Date	Package
TransitionDrawable.java	API Doc	Android 5.1 API	8485	Thu Mar 12 22:22:30 GMT 2015	android.graphics.drawable

TransitionDrawable

• java.lang.Object
  • LayerDrawable

Fields Summary
private static final int	TRANSITION_STARTING A transition is about to start.
private static final int	TRANSITION_RUNNING The transition has started and the animation is in progress
private static final int	TRANSITION_NONE No transition will be applied
private int	mTransitionState The current state of the transition. One of {@link #TRANSITION_STARTING}, {@link #TRANSITION_RUNNING} and {@link #TRANSITION_NONE}
private boolean	mReverse
private long	mStartTimeMillis
private int	mFrom
private int	mTo
private int	mDuration
private int	mOriginalDuration
private int	mAlpha
private boolean	mCrossFade

Constructors Summary
public TransitionDrawable(Drawable[] layers) Create a new transition drawable with the specified list of layers. At least 2 layers are required for this drawable to work properly. this(new TransitionState(null, null, null), layers);
TransitionDrawable() Create a new transition drawable with no layer. To work correctly, at least 2 layers must be added to this drawable. see #TransitionDrawable(Drawable[]) this(new TransitionState(null, null, null), (Resources) null);
private TransitionDrawable(TransitionState state, android.content.res.Resources res) super(state, res);
private TransitionDrawable(TransitionState state, Drawable[] layers) super(layers, state);

Methods Summary
LayerState	createConstantState(LayerState state, android.content.res.Resources res) return new TransitionState((TransitionState) state, this, res);
public void	draw(android.graphics.Canvas canvas) boolean done = true; switch (mTransitionState) { case TRANSITION_STARTING: mStartTimeMillis = SystemClock.uptimeMillis(); done = false; mTransitionState = TRANSITION_RUNNING; break; case TRANSITION_RUNNING: if (mStartTimeMillis >= 0) { float normalized = (float) (SystemClock.uptimeMillis() - mStartTimeMillis) / mDuration; done = normalized >= 1.0f; normalized = Math.min(normalized, 1.0f); mAlpha = (int) (mFrom + (mTo - mFrom) * normalized); } break; } final int alpha = mAlpha; final boolean crossFade = mCrossFade; final ChildDrawable[] array = mLayerState.mChildren; if (done) { // the setAlpha() calls below trigger invalidation and redraw. If we're done, just draw // the appropriate drawable[s] and return if (!crossFade || alpha == 0) { array[0].mDrawable.draw(canvas); } if (alpha == 0xFF) { array[1].mDrawable.draw(canvas); } return; } Drawable d; d = array[0].mDrawable; if (crossFade) { d.setAlpha(255 - alpha); } d.draw(canvas); if (crossFade) { d.setAlpha(0xFF); } if (alpha > 0) { d = array[1].mDrawable; d.setAlpha(alpha); d.draw(canvas); d.setAlpha(0xFF); } if (!done) { invalidateSelf(); }
public boolean	isCrossFadeEnabled() Indicates whether the cross fade is enabled for this transition. return True if cross fading is enabled, false otherwise. return mCrossFade;
public void	resetTransition() Show only the first layer. mAlpha = 0; mTransitionState = TRANSITION_NONE; invalidateSelf();
public void	reverseTransition(int duration) Reverses the transition, picking up where the transition currently is. If the transition is not currently running, this will start the transition with the specified duration. If the transition is already running, the last known duration will be used. param duration The duration to use if no transition is running. final long time = SystemClock.uptimeMillis(); // Animation is over if (time - mStartTimeMillis > mDuration) { if (mTo == 0) { mFrom = 0; mTo = 255; mAlpha = 0; mReverse = false; } else { mFrom = 255; mTo = 0; mAlpha = 255; mReverse = true; } mDuration = mOriginalDuration = duration; mTransitionState = TRANSITION_STARTING; invalidateSelf(); return; } mReverse = !mReverse; mFrom = mAlpha; mTo = mReverse ? 0 : 255; mDuration = (int) (mReverse ? time - mStartTimeMillis : mOriginalDuration - (time - mStartTimeMillis)); mTransitionState = TRANSITION_STARTING;
public void	setCrossFadeEnabled(boolean enabled) Enables or disables the cross fade of the drawables. When cross fade is disabled, the first drawable is always drawn opaque. With cross fade enabled, the first drawable is drawn with the opposite alpha of the second drawable. Cross fade is disabled by default. param enabled True to enable cross fading, false otherwise. mCrossFade = enabled;
public void	startTransition(int durationMillis) Begin the second layer on top of the first layer. param durationMillis The length of the transition in milliseconds mFrom = 0; mTo = 255; mAlpha = 0; mDuration = mOriginalDuration = durationMillis; mReverse = false; mTransitionState = TRANSITION_STARTING; invalidateSelf();