Package io.flutter.util

Class ViewUtils

java.lang.Object

io.flutter.util.ViewUtils

public final class ViewUtils
extends Object

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static interface	ViewUtils.DisplayUpdater
static interface	ViewUtils.ViewVisitor	Allows to visit a view.

Constructor Summary

Constructors

Constructor	Description
ViewUtils()

Method Summary

Modifier and Type	Method	Description
static void	calculateMaximumDisplayMetrics(Context context, ViewUtils.DisplayUpdater updater)	Calculates the maximum display metrics for the given context, and pushes the metric data to the updater.
static boolean	childHasFocus(View root)	Determines if the current view or any descendant view has focus.
static int	generateViewId(int fallbackId)	Generates a view id.
static Activity	getActivity(Context context)	Retrieves the Activity from a given Context.
static boolean	hasChildViewOfType(View root, Class<? extends View>[] viewTypes)	Returns true if the root or any child view is an instance of the given types.
static boolean	traverseHierarchy(View root, ViewUtils.ViewVisitor visitor)	Traverses the view hierarchy in pre-order and runs the visitor for each child view including the root view.

Methods inherited from class java.lang.Object

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

Constructor Detail

ViewUtils

public ViewUtils()

Method Detail

calculateMaximumDisplayMetrics

public static void calculateMaximumDisplayMetrics(@Nullable
                                                  Context context,
                                                  @NonNull
                                                  ViewUtils.DisplayUpdater updater)

Calculates the maximum display metrics for the given context, and pushes the metric data to the updater.

getActivity

@Nullable
public static Activity getActivity(@Nullable
                                   Context context)

Retrieves the Activity from a given Context.

This method will recursively traverse up the context chain if it is a ContextWrapper until it finds the first instance of the base context that is an Activity.

generateViewId

public static int generateViewId(int fallbackId)

Generates a view id.

In API level 17 and above, this ID is unique. Below 17, the fallback id is used instead.

Parameters:

fallbackId - the fallback id.

Returns:

the view id.

childHasFocus

public static boolean childHasFocus(@Nullable
                                    View root)

Determines if the current view or any descendant view has focus.

Parameters:

root - The root view.

Returns:

True if the current view or any descendant view has focus.

hasChildViewOfType

public static boolean hasChildViewOfType(@Nullable
                                         View root,
                                         Class<? extends View>[] viewTypes)

Returns true if the root or any child view is an instance of the given types.

Parameters:

root - The root view.

viewTypes - The types of views.

Returns:

true if any child view is an instance of any of the given types.

traverseHierarchy

public static boolean traverseHierarchy(@Nullable
                                        View root,
                                        @NonNull
                                        ViewUtils.ViewVisitor visitor)

Traverses the view hierarchy in pre-order and runs the visitor for each child view including the root view.

If the visitor returns true, the traversal stops, and the method returns true.

If the visitor returns false, the traversal continues until all views are visited.

Parameters:

root - The root view.

visitor - The visitor.

Returns:

true if the visitor returned true for a given view.