com.bumptech.glide.request.target

Class CustomViewTarget<T extends View,Z>

java.lang.Object

com.bumptech.glide.request.target.CustomViewTarget<T,Z>

Type Parameters:

T - The specific subclass of view wrapped by this target.

Z - The resource type this target will receive.

All Implemented Interfaces:

LifecycleListener, Target<Z>

public abstract class CustomViewTarget<T extends View,Z>
extends Object
implements Target<Z>

A base Target for loading Bitmaps into Views that provides default implementations for most methods and can determine the size of views using a ViewTreeObserver.OnDrawListener.

Field Summary

Fields

Modifier and Type	Field and Description
protected T	view

Fields inherited from interface com.bumptech.glide.request.target.Target

SIZE_ORIGINAL

Constructor Summary

Constructors

Constructor and Description
CustomViewTarget(T view) Constructor that defaults waitForLayout to false.

Method Summary

Modifier and Type	Method and Description
CustomViewTarget<T,Z>	clearOnDetach() Clears the View's Request when the View is detached from its Window and restarts the Request when the View is re-attached from its Window.
Request	getRequest() Returns any stored request using View.getTag().
void	getSize(SizeReadyCallback cb) Determines the size of the view by first checking View.getWidth() and View.getHeight().
T	getView() Returns the wrapped View.
void	onDestroy() Callback for when Fragment.onDestroy()} or Activity.onDestroy() is called.
void	onLoadCleared(Drawable placeholder) A mandatory lifecycle callback that is called when a load is cancelled and its resources are freed.
void	onLoadStarted(Drawable placeholder) A lifecycle callback that is called when a load is started.
protected abstract void	onResourceCleared(Drawable placeholder) A required callback invoked when the resource is no longer valid and must be freed.
protected void	onResourceLoading(Drawable placeholder) An optional callback invoked when a resource load is started.
void	onStart() Callback for when Fragment.onStart()} or Activity.onStart() is called.
void	onStop() Callback for when Fragment.onStop()} or Activity.onStop()} is called.
void	removeCallback(SizeReadyCallback cb) Removes the given callback from the pending set if it's still retained.
void	setRequest(Request request) Stores the request using View.setTag(Object).
String	toString()
CustomViewTarget<T,Z>	useTagId(int tagId) Override the android resource id to store temporary state allowing loads to be automatically cancelled and resources re-used in scrolling lists.
CustomViewTarget<T,Z>	waitForLayout() Indicates that Glide should always wait for any pending layout pass before checking for the size an View.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Methods inherited from interface com.bumptech.glide.request.target.Target

onLoadFailed, onResourceReady

Field Detail

view

protected final T extends View view

Constructor Detail

CustomViewTarget

public CustomViewTarget(@NonNull
                        T view)

Constructor that defaults waitForLayout to false.

Method Detail

onResourceCleared

protected abstract void onResourceCleared(@Nullable
                                          Drawable placeholder)

A required callback invoked when the resource is no longer valid and must be freed.

You must ensure that any current Drawable received in Target.onResourceReady(Object, Transition) is no longer used before redrawing the container (usually a View) or changing its visibility. Not doing so will result in crashes in your app.

Parameters:

placeholder - The placeholder drawable to optionally show, or null.

onResourceLoading

protected void onResourceLoading(@Nullable
                                 Drawable placeholder)

An optional callback invoked when a resource load is started.

Parameters:

placeholder - The placeholder drawable to optionally show, or null.

See Also:

Target.onLoadStarted(Drawable)

onStart

public void onStart()

Description copied from interface: LifecycleListener

Callback for when Fragment.onStart()} or Activity.onStart() is called.

Specified by:

onStart in interface LifecycleListener

onStop

public void onStop()

Description copied from interface: LifecycleListener

Callback for when Fragment.onStop()} or Activity.onStop()} is called.

Specified by:

onStop in interface LifecycleListener

onDestroy

public void onDestroy()

Description copied from interface: LifecycleListener

Callback for when Fragment.onDestroy()} or Activity.onDestroy() is called.

Specified by:

onDestroy in interface LifecycleListener

waitForLayout

@NonNull
public final CustomViewTarget<T,Z> waitForLayout()

Indicates that Glide should always wait for any pending layout pass before checking for the size an View.

By default, Glide will only wait for a pending layout pass if it's unable to resolve the size from the ViewGroup.LayoutParams or valid non-zero values for View.getWidth() and View.getHeight().

Because calling this method forces Glide to wait for the layout pass to occur before starting loads, setting this parameter to true can cause Glide to asynchronous load an image even if it's in the memory cache. The load will happen asynchronously because Glide has to wait for a layout pass to occur, which won't necessarily happen in the same frame as when the image is requested. As a result, using this method can resulting in flashing in some cases and should be used sparingly.

If the ViewGroup.LayoutParams of the wrapped View are set to fixed sizes, they will still be used instead of the View's dimensions even if this method is called. This parameter is a fallback only.

clearOnDetach

@NonNull
public final CustomViewTarget<T,Z> clearOnDetach()

Clears the View's Request when the View is detached from its Window and restarts the Request when the View is re-attached from its Window.

This is an experimental API that may be removed in a future version.

Using this method can save memory by allowing Glide to more eagerly clear resources when transitioning screens or swapping adapters in scrolling views. However it also substantially increases the odds that images will not be in memory if users subsequently return to a screen where images were previously loaded. Whether or not this happens will depend on the number of images loaded in the new screen and the size of the memory cache. Increasing the size of the memory cache can improve this behavior but it largely negates the memory benefits of using this method.

Use this method with caution and measure your memory usage to ensure that it's actually improving your memory usage in the cases you care about.

useTagId

public final CustomViewTarget<T,Z> useTagId(@IdRes
                                            int tagId)

Override the android resource id to store temporary state allowing loads to be automatically cancelled and resources re-used in scrolling lists.

Unlike ViewTarget, it is not necessary to set a custom tag id if your app uses View.setTag(Object). It is only necessary if loading several Glide resources into the same view, for example one foreground and one background view.

Parameters:

tagId - The android resource id to use.

getView

@NonNull
public final T getView()

Returns the wrapped View.

getSize

public final void getSize(@NonNull
                          SizeReadyCallback cb)

Determines the size of the view by first checking View.getWidth() and View.getHeight(). If one or both are zero, it then checks the view's ViewGroup.LayoutParams. If one or both of the params width and height are less than or equal to zero, it then adds an ViewTreeObserver.OnPreDrawListener which waits until the view has been measured before calling the callback with the view's drawn width and height.

Specified by:

getSize in interface Target<Z>

Parameters:

cb - The callback that must be called when the size of the target has been determined

removeCallback

public final void removeCallback(@NonNull
                                 SizeReadyCallback cb)

Description copied from interface: Target

Removes the given callback from the pending set if it's still retained.

Specified by:

removeCallback in interface Target<Z>

Parameters:

cb - The callback to remove.

onLoadStarted

public final void onLoadStarted(@Nullable
                                Drawable placeholder)

Description copied from interface: Target

A lifecycle callback that is called when a load is started.

Note - This may not be called for every load, it is possible for example for loads to fail before the load starts (when the model object is null).

Note - This method may be called multiple times before any other lifecycle method is called. Loads can be paused and restarted due to lifecycle or connectivity events and each restart may cause a call here.

Specified by:

onLoadStarted in interface Target<Z>

Parameters:

placeholder - The placeholder drawable to optionally show, or null.

onLoadCleared

public final void onLoadCleared(@Nullable
                                Drawable placeholder)

Description copied from interface: Target

A mandatory lifecycle callback that is called when a load is cancelled and its resources are freed.

You must ensure that any current Drawable received in Target.onResourceReady(Object, Transition) is no longer used before redrawing the container (usually a View) or changing its visibility.

Specified by:

onLoadCleared in interface Target<Z>

Parameters:

placeholder - The placeholder drawable to optionally show, or null.

setRequest

public final void setRequest(@Nullable
                             Request request)

Stores the request using View.setTag(Object).

Specified by:

setRequest in interface Target<Z>

Parameters:

request -

getRequest

@Nullable
public final Request getRequest()

Returns any stored request using View.getTag().

Specified by:

getRequest in interface Target<Z>

toString

public String toString()

Overrides:

toString in class Object