ViewTreeObserver Class
Definition
Important
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A view tree observer is used to register listeners that can be notified of global changes in the view tree.
[Android.Runtime.Register("android/view/ViewTreeObserver", DoNotGenerateAcw=true)]
public sealed class ViewTreeObserver : Java.Lang.Object[<Android.Runtime.Register("android/view/ViewTreeObserver", DoNotGenerateAcw=true)>]
type ViewTreeObserver = class
inherit Object- Inheritance
- Attributes
Remarks
A view tree observer is used to register listeners that can be notified of global changes in the view tree. Such global events include, but are not limited to, layout of the whole tree, beginning of the drawing pass, touch mode change....
A ViewTreeObserver should never be instantiated by applications as it is provided by the views hierarchy. Refer to android.view.View#getViewTreeObserver() for more information.
Java documentation for android.view.ViewTreeObserver.
Portions of this page are modifications based on work created and shared by the Android Open Source Project and used according to terms described in the Creative Commons 2.5 Attribution License.
Properties
| Class |
Returns the runtime class of this |
| Handle |
The handle to the underlying Android instance. (Inherited from Object) |
| IsAlive |
Indicates whether this ViewTreeObserver is alive. |
| JniIdentityHashCode | (Inherited from Object) |
| JniPeerMembers | |
| PeerReference | (Inherited from Object) |
| ThresholdClass |
This API supports the Mono for Android infrastructure and is not intended to be used directly from your code. (Inherited from Object) |
| ThresholdType |
This API supports the Mono for Android infrastructure and is not intended to be used directly from your code. (Inherited from Object) |
Methods
| AddOnDrawListener(ViewTreeObserver+IOnDrawListener) |
Register a callback to be invoked when the view tree is about to be drawn. |
| AddOnGlobalFocusChangeListener(ViewTreeObserver+IOnGlobalFocusChangeListener) |
Register a callback to be invoked when the focus state within the view tree changes. |
| AddOnGlobalLayoutListener(ViewTreeObserver+IOnGlobalLayoutListener) |
Register a callback to be invoked when the global layout state or the visibility of views within the view tree changes |
| AddOnPreDrawListener(ViewTreeObserver+IOnPreDrawListener) |
Register a callback to be invoked when the view tree is about to be drawn |
| AddOnScrollChangedListener(ViewTreeObserver+IOnScrollChangedListener) |
Register a callback to be invoked when a view has been scrolled. |
| AddOnSystemGestureExclusionRectsChangedListener(IConsumer) |
Add a listener to be notified when the tree's <em>transformed</em> gesture exclusion rects change. |
| AddOnTouchModeChangeListener(ViewTreeObserver+IOnTouchModeChangeListener) |
Register a callback to be invoked when the invoked when the touch mode changes. |
| AddOnWindowAttachListener(ViewTreeObserver+IOnWindowAttachListener) |
Register a callback to be invoked when the view hierarchy is attached to a window. |
| AddOnWindowFocusChangeListener(ViewTreeObserver+IOnWindowFocusChangeListener) |
Register a callback to be invoked when the window focus state within the view tree changes. |
| AddOnWindowVisibilityChangeListener(ViewTreeObserver+IOnWindowVisibilityChangeListener) | |
| Clone() |
Creates and returns a copy of this object. (Inherited from Object) |
| DispatchOnDraw() |
Notifies registered listeners that the drawing pass is about to start. |
| DispatchOnGlobalLayout() |
Notifies registered listeners that a global layout happened. |
| DispatchOnPreDraw() |
Notifies registered listeners that the drawing pass is about to start. |
| Dispose() | (Inherited from Object) |
| Dispose(Boolean) | (Inherited from Object) |
| Equals(Object) |
Indicates whether some other object is "equal to" this one. (Inherited from Object) |
| GetHashCode() |
Returns a hash code value for the object. (Inherited from Object) |
| JavaFinalize() |
Called by the garbage collector on an object when garbage collection determines that there are no more references to the object. (Inherited from Object) |
| Notify() |
Wakes up a single thread that is waiting on this object's monitor. (Inherited from Object) |
| NotifyAll() |
Wakes up all threads that are waiting on this object's monitor. (Inherited from Object) |
| RegisterFrameCommitCallback(IRunnable) |
Adds a frame commit callback. |
| RemoveGlobalOnLayoutListener(ViewTreeObserver+IOnGlobalLayoutListener) |
Obsolete.
Remove a previously installed global layout callback |
| RemoveOnDrawListener(ViewTreeObserver+IOnDrawListener) |
Remove a previously installed pre-draw callback. |
| RemoveOnGlobalFocusChangeListener(ViewTreeObserver+IOnGlobalFocusChangeListener) |
Remove a previously installed focus change callback. |
| RemoveOnGlobalLayoutListener(ViewTreeObserver+IOnGlobalLayoutListener) |
Remove a previously installed global layout callback |
| RemoveOnPreDrawListener(ViewTreeObserver+IOnPreDrawListener) |
Remove a previously installed pre-draw callback |
| RemoveOnScrollChangedListener(ViewTreeObserver+IOnScrollChangedListener) |
Remove a previously installed scroll-changed callback |
| RemoveOnSystemGestureExclusionRectsChangedListener(IConsumer) |
Unsubscribe the given listener from gesture exclusion rect changes. |
| RemoveOnTouchModeChangeListener(ViewTreeObserver+IOnTouchModeChangeListener) |
Remove a previously installed touch mode change callback |
| RemoveOnWindowAttachListener(ViewTreeObserver+IOnWindowAttachListener) |
Remove a previously installed window attach callback. |
| RemoveOnWindowFocusChangeListener(ViewTreeObserver+IOnWindowFocusChangeListener) |
Remove a previously installed window focus change callback. |
| RemoveOnWindowVisibilityChangeListener(ViewTreeObserver+IOnWindowVisibilityChangeListener) | |
| SetHandle(IntPtr, JniHandleOwnership) |
Sets the Handle property. (Inherited from Object) |
| ToArray<T>() | (Inherited from Object) |
| ToString() |
Returns a string representation of the object. (Inherited from Object) |
| UnregisterFrameCommitCallback(IRunnable) |
Attempts to remove the given callback from the list of pending frame complete callbacks. |
| UnregisterFromRuntime() | (Inherited from Object) |
| Wait() |
Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>. (Inherited from Object) |
| Wait(Int64) |
Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed. (Inherited from Object) |
| Wait(Int64, Int32) |
Causes the current thread to wait until it is awakened, typically by being <em>notified</em> or <em>interrupted</em>, or until a certain amount of real time has elapsed. (Inherited from Object) |
Events
| Draw | |
| GlobalFocusChange | |
| GlobalLayout | |
| PreDraw | |
| ScrollChanged | |
| TouchModeChange | |
| WindowAttached | |
| WindowDetached | |
| WindowFocusChange | |
| WindowVisibilityChange |
Explicit Interface Implementations
| IJavaPeerable.Disposed() | (Inherited from Object) |
| IJavaPeerable.DisposeUnlessReferenced() | (Inherited from Object) |
| IJavaPeerable.Finalized() | (Inherited from Object) |
| IJavaPeerable.JniManagedPeerState | (Inherited from Object) |
| IJavaPeerable.SetJniIdentityHashCode(Int32) | (Inherited from Object) |
| IJavaPeerable.SetJniManagedPeerState(JniManagedPeerStates) | (Inherited from Object) |
| IJavaPeerable.SetPeerReference(JniObjectReference) | (Inherited from Object) |
Extension Methods
| JavaCast<TResult>(IJavaObject) |
Performs an Android runtime-checked type conversion. |
| JavaCast<TResult>(IJavaObject) | |
| GetJniTypeName(IJavaPeerable) | |