io.flutter.util.ViewUtils Class Reference

Classes
interface	DisplayUpdater
interface	ViewVisitor

Static Public Member Functions
static void	calculateMaximumDisplayMetrics ( @Nullable Context context, @NonNull DisplayUpdater updater)
static Activity	getActivity (@Nullable Context context)
static boolean	childHasFocus (@Nullable View root)
static boolean	hasChildViewOfType (@Nullable View root, Class<? extends View >[] viewTypes)
static boolean	traverseHierarchy (@Nullable View root, @NonNull ViewVisitor visitor)

Detailed Description

Definition at line 17 of file ViewUtils.java.

Member Function Documentation

calculateMaximumDisplayMetrics()

static void io.flutter.util.ViewUtils.calculateMaximumDisplayMetrics ( @Nullable Context  context, @NonNull DisplayUpdater  updater  )

inlinestatic

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

Definition at line 27 of file ViewUtils.java.

                                                                  {
    Activity activity = getActivity(context);
    if (activity != null) {
      WindowMetrics metrics =
          WindowMetricsCalculator.getOrCreate().computeMaximumWindowMetrics(activity);
      float width = metrics.getBounds().width();
      float height = metrics.getBounds().height();
      float density = context.getResources().getDisplayMetrics().density;
      updater.updateDisplayMetrics(width, height, density);
    }
  }

childHasFocus()

static boolean io.flutter.util.ViewUtils.childHasFocus ( @Nullable View  root )

inlinestatic

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.

Definition at line 67 of file ViewUtils.java.

                                                           {
    return traverseHierarchy(root, (View view) -> view.hasFocus());
  }

getActivity()

static Activity io.flutter.util.ViewUtils.getActivity ( @Nullable Context  context )

inlinestatic

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.

Definition at line 47 of file ViewUtils.java.

                                                                {
    if (context == null) {
      return null;
    }
    if (context instanceof Activity) {
      return (Activity) context;
    }
    if (context instanceof ContextWrapper) {
      // Recurse up chain of base contexts until we find an Activity.
      return getActivity(((ContextWrapper) context).getBaseContext());
    }
    return null;
  }

hasChildViewOfType()

static boolean io.flutter.util.ViewUtils.hasChildViewOfType ( @Nullable View  root, Class<? extends View >[]  viewTypes  )

inlinestatic

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.

Definition at line 78 of file ViewUtils.java.

                                                                                                   {
    return traverseHierarchy(
        root,
        (View view) -> {
          for (int i = 0; i < viewTypes.length; i++) {
            final Class<? extends View> viewType = viewTypes[i];
            if (viewType.isInstance(view)) {
              return true;
            }
          }
          return false;
        });
  }

traverseHierarchy()

static boolean io.flutter.util.ViewUtils.traverseHierarchy ( @Nullable View  root, @NonNull ViewVisitor  visitor  )

inlinestatic

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.

Definition at line 109 of file ViewUtils.java.

                                                                                             {
    if (root == null) {
      return false;
    }
    if (visitor.run(root)) {
      return true;
    }
    if (root instanceof ViewGroup) {
      final ViewGroup viewGroup = (ViewGroup) root;
      for (int idx = 0; idx < viewGroup.getChildCount(); idx++) {
        if (traverseHierarchy(viewGroup.getChildAt(idx), visitor)) {
          return true;
        }
      }
    }
    return false;
  }

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The documentation for this class was generated from the following file:

• shell/platform/android/io/flutter/util/ViewUtils.java