diff options
Diffstat (limited to 'core/java/android/transition/Fade.java')
| -rw-r--r-- | core/java/android/transition/Fade.java | 45 |
1 files changed, 41 insertions, 4 deletions
diff --git a/core/java/android/transition/Fade.java b/core/java/android/transition/Fade.java index 5f948bd..8edb1ff 100644 --- a/core/java/android/transition/Fade.java +++ b/core/java/android/transition/Fade.java @@ -30,6 +30,24 @@ import android.view.ViewGroup; * {@link View#setVisibility(int)} state of the view as well as whether it * is parented in the current view hierarchy. * + * <p>The ability of this transition to fade out a particular view, and the + * way that that fading operation takes place, is based on + * the situation of the view in the view hierarchy. For example, if a view was + * simply removed from its parent, then the view will be added into a {@link + * android.view.ViewGroupOverlay} while fading. If a visible view is + * changed to be {@link View#GONE} or {@link View#INVISIBLE}, then the + * visibility will be changed to {@link View#VISIBLE} for the duration of + * the animation. However, if a view is in a hierarchy which is also altering + * its visibility, the situation can be more complicated. In general, if a + * view that is no longer in the hierarchy in the end scene still has a + * parent (so its parent hierarchy was removed, but it was not removed from + * its parent), then it will be left alone to avoid side-effects from + * improperly removing it from its parent. The only exception to this is if + * the previous {@link Scene} was + * {@link Scene#getSceneForLayout(android.view.ViewGroup, int, android.content.Context) + * created from a layout resource file}, then it is considered safe to un-parent + * the starting scene view in order to fade it out.</p> + * * <p>A Fade transition can be described in a resource file by using the * tag <code>fade</code>, along with the standard * attributes of {@link android.R.styleable#Fade} and @@ -167,7 +185,7 @@ public class Fade extends Visibility { if ((mFadingMode & OUT) != OUT) { return null; } - View view; + View view = null; View startView = (startValues != null) ? startValues.view : null; View endView = (endValues != null) ? endValues.view : null; if (DBG) { @@ -177,9 +195,28 @@ public class Fade extends Visibility { View overlayView = null; View viewToKeep = null; if (endView == null || endView.getParent() == null) { - // view was removed: add the start view to the Overlay - view = startView; - overlayView = view; + if (endView != null) { + // endView was removed from its parent - add it to the overlay + view = overlayView = endView; + } else if (startView != null) { + // endView does not exist. Use startView only under certain + // conditions, because placing a view in an overlay necessitates + // it being removed from its current parent + if (startView.getParent() == null) { + // no parent - safe to use + view = overlayView = startView; + } else if (startView.getParent() instanceof View && + startView.getParent().getParent() == null) { + View startParent = (View) startView.getParent(); + int id = startParent.getId(); + if (id != View.NO_ID && sceneRoot.findViewById(id) != null && mCanRemoveViews) { + // no parent, but its parent is unparented but the parent + // hierarchy has been replaced by a new hierarchy with the same id + // and it is safe to un-parent startView + view = overlayView = startView; + } + } + } } else { // visibility change if (endVisibility == View.INVISIBLE) { |