Package icyllis.modernui.view

Interface ViewParent

All Known Implementing Classes:
AbsListView, AbsoluteLayout, AbsSpinner, AdapterView, CoordinatorLayout, DropDownListView, ExpandableListView, FragmentContainerView, FrameLayout, GridLayout, GridView, HorizontalScrollView, LinearLayout, ListMenuItemView, ListView, MenuPopupWindow.MenuDropDownListView, NestedScrollView, RadioGroup, RelativeLayout, RelativeRadioGroup, ScrollView, Spinner, TableLayout, TableRow, TestFragment.TestLinearLayout, ViewGroup, ViewPager, ViewRoot, WindowGroup
public interface ViewParent
Defines an object that can work as a parent of a View.

  • Method Details

    • getParent

      @Nullable ViewParent getParent()
      Returns the parent of this ViewParent.
      Returns:
      the parent or null if the parent is not available

    • requestLayout

      void requestLayout()
      Called when something has changed which has invalidated the layout of a child of this view parent. This will schedule a layout pass of the view tree.

    • isLayoutRequested

      boolean isLayoutRequested()
      Indicates whether layout was requested on this view parent.
      Returns:
      true if layout was requested, false otherwise

    • requestChildFocus

      void requestChildFocus(View child, View focused)
      Called when a child of this parent wants focus
      Parameters:
      child - The child of this ViewParent that wants focus. This view will contain the focused view. It is not necessarily the view that actually has focus.
      focused - The view that is a descendant of child that actually has focus

    • clearChildFocus

      void clearChildFocus(View child)
      Called when a child of this parent is giving up focus
      Parameters:
      child - The view that is giving up focus

    • getChildVisibleRect

      boolean getChildVisibleRect(View child, Rect r, @Nullable Point offset)
      Compute the visible part of a rectangular region defined in terms of a child view's coordinates.

      Returns the clipped visible part of the rectangle r, defined in the child's local coordinate system. r is modified by this method to contain the result, expressed in the global (root) coordinate system.

      The resulting rectangle is always axis aligned. If a rotation is applied to a node in the View hierarchy, the result is the axis-aligned bounding box of the visible rectangle.

      Parameters:
      child - A child View, whose rectangular visible region we want to compute
      r - The input rectangle, defined in the child coordinate system. Will be overwritten to contain the resulting visible rectangle, expressed in global (root) coordinates
      offset - The input coordinates of a point, defined in the child coordinate system. As with the r parameter, this will be overwritten to contain the global (root) coordinates of that point. A null value is valid (in case you are not interested in this result)
      Returns:
      true if the resulting rectangle is not empty, false otherwise

    • focusSearch

      View focusSearch(View v, int direction)
      Find the nearest view in the specified direction that wants to take focus
      Parameters:
      v - The view that currently has focus
      direction - One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT

    • keyboardNavigationClusterSearch

      View keyboardNavigationClusterSearch(View currentCluster, int direction)
      Find the nearest keyboard navigation cluster in the specified direction. This does not actually give focus to that cluster.
      Parameters:
      currentCluster - The starting point of the search. Null means the current cluster is not found yet
      direction - Direction to look
      Returns:
      The nearest keyboard navigation cluster in the specified direction, or null if none can be found

    • bringChildToFront

      void bringChildToFront(View child)
      Change the z order of the child, so it's on top of all other children. This ordering change may affect layout, if this container uses an order-dependent layout scheme (e.g., LinearLayout).
      Parameters:
      child - The child to bring to the top of the z order

    • focusableViewAvailable

      void focusableViewAvailable(View v)
      Tells the parent that a new focusable view has become available. This is to handle transitions from the case where there are no focusable views to the case where the first focusable view appears.
      Parameters:
      v - The view that has become newly focusable

    • showContextMenuForChild

      boolean showContextMenuForChild(View originalView, float x, float y)
      Shows the context menu for the specified view or its ancestors anchored to the specified view-relative coordinate.

      In most cases, a subclass does not need to override this. However, if the subclass is added directly to the window manager (for example, ViewManager.addView(View, ViewGroup.LayoutParams)) then it should override this and show the context menu.

      Parameters:
      originalView - the source view where the context menu was first invoked
      x - the X coordinate in pixels relative to the original view to which the menu should be anchored, or Float.NaN to disable anchoring
      y - the Y coordinate in pixels relative to the original view to which the menu should be anchored, or Float.NaN to disable anchoring
      Returns:
      true if the context menu was shown, false otherwise

    • createContextMenu

      void createContextMenu(ContextMenu menu)
      Have the parent populate the specified context menu if it has anything to add (and then recurse on its parent).
      Parameters:
      menu - The menu to populate

    • startActionModeForChild

      ActionMode startActionModeForChild(View originalView, ActionMode.Callback callback, int type)
      Start an action mode of a specific type for the specified view.

      In most cases, a subclass does not need to override this. However, if the subclass is added directly to the window manager (for example, ViewManager.addView(View, ViewGroup.LayoutParams)) then it should override this and start the action mode.

      Parameters:
      originalView - The source view where the action mode was first invoked
      callback - The callback that will handle lifecycle events for the action mode
      type - One of ActionMode.TYPE_PRIMARY or ActionMode.TYPE_FLOATING.
      Returns:
      The new action mode if it was started, null otherwise

    • childDrawableStateChanged

      void childDrawableStateChanged(View child)
      This method is called on the parent when a child's drawable state has changed.
      Parameters:
      child - The child whose drawable state has changed.

    • requestDisallowInterceptTouchEvent

      void requestDisallowInterceptTouchEvent(boolean disallowIntercept)
      Called when a child does not want this parent and its ancestors to intercept touch events with ViewGroup.onInterceptTouchEvent(MotionEvent).

      This parent should pass this call onto its parents. This parent must obey this request for the duration of the touch (that is, only clear the flag after this parent has received an up or a cancel.

      Parameters:
      disallowIntercept - True if the child does not want the parent to intercept touch events.

    • requestChildRectangleOnScreen

      boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate)
      Called when a child of this group wants a particular rectangle to be positioned onto the screen. ViewGroups overriding this can trust that:
      • child will be a direct child of this group
      • rectangle will be in the child's content coordinates

      ViewGroups overriding this should uphold the contract:

      • nothing will change if the rectangle is already visible
      • the view port will be scrolled only just enough to make the rectangle visible
      Parameters:
      child - The direct child making the request.
      rectangle - The rectangle in the child's coordinates the child wishes to be on the screen.
      immediate - True to forbid animated or delayed scrolling, false otherwise
      Returns:
      Whether the group scrolled to handle the operation

    • childHasTransientStateChanged

      void childHasTransientStateChanged(View child, boolean hasTransientState)
      Called when a child view now has or no longer is tracking transient state.

      "Transient state" is any state that a View might hold that is not expected to be reflected in the data model that the View currently presents. This state only affects the presentation to the user within the View itself, such as the current state of animations in progress or the state of a text selection operation.

      Transient state is useful for hinting to other components of the View system that a particular view is tracking something complex but encapsulated. A ListView for example may acknowledge that list item Views with transient state should be preserved within their position or stable item ID instead of treating that view as trivially replaceable by the backing adapter. This allows adapter implementations to be simpler instead of needing to track the state of item view animations in progress such that they could be restored in the event of an unexpected recycling and rebinding of attached item views.

      This method is called on a parent view when a child view or a view within its subtree begins or ends tracking of internal transient state.

      Parameters:
      child - Child view whose state has changed
      hasTransientState - true if this child has transient state

    • canResolveLayoutDirection

      boolean canResolveLayoutDirection()
      Tells if this view parent can resolve the layout direction. See View.setLayoutDirection(int)
      Returns:
      True if this view parent can resolve the layout direction.

    • isLayoutDirectionResolved

      boolean isLayoutDirectionResolved()
      Tells if this view parent layout direction is resolved. See View.setLayoutDirection(int)
      Returns:
      True if this view parent layout direction is resolved.

    • getLayoutDirection

      int getLayoutDirection()
      Return this view parent layout direction. See View.getLayoutDirection()
      Returns:
      View.LAYOUT_DIRECTION_RTL if the layout direction is RTL or returns View.LAYOUT_DIRECTION_LTR if the layout direction is not RTL.

    • canResolveTextDirection

      boolean canResolveTextDirection()
      Tells if this view parent can resolve the text direction. See View.setTextDirection(int)
      Returns:
      True if this view parent can resolve the text direction.

    • isTextDirectionResolved

      boolean isTextDirectionResolved()
      Tells if this view parent text direction is resolved. See View.setTextDirection(int)
      Returns:
      True if this view parent text direction is resolved.

    • getTextDirection

      int getTextDirection()
      Return this view parent text direction. See View.getTextDirection()
      Returns:
      the resolved text direction. Returns one of:

      View.TEXT_DIRECTION_FIRST_STRONG View.TEXT_DIRECTION_ANY_RTL, View.TEXT_DIRECTION_LTR, View.TEXT_DIRECTION_RTL, View.TEXT_DIRECTION_LOCALE

    • canResolveTextAlignment

      boolean canResolveTextAlignment()
      Tells if this view parent can resolve the text alignment. See View.setTextAlignment(int)
      Returns:
      True if this view parent can resolve the text alignment.

    • isTextAlignmentResolved

      boolean isTextAlignmentResolved()
      Tells if this view parent text alignment is resolved. See View.setTextAlignment(int)
      Returns:
      True if this view parent text alignment is resolved.

    • getTextAlignment

      int getTextAlignment()
      Return this view parent text alignment. See View.getTextAlignment()
      Returns:
      the resolved text alignment. Returns one of:

      View.TEXT_ALIGNMENT_GRAVITY, View.TEXT_ALIGNMENT_CENTER, View.TEXT_ALIGNMENT_TEXT_START, View.TEXT_ALIGNMENT_TEXT_END, View.TEXT_ALIGNMENT_VIEW_START, View.TEXT_ALIGNMENT_VIEW_END

    • onStartNestedScroll

      boolean onStartNestedScroll(@NonNull View child, @NonNull View target, int axes, int type)
      React to a descendant view initiating a nestable scroll operation, claiming the nested scroll operation if appropriate.

      This method will be called in response to a descendant view invoking View.startNestedScroll(int, int). Each parent up the view hierarchy will be given an opportunity to respond and claim the nested scrolling operation by returning true.

      This method may be overridden by ViewParent implementations to indicate when the view is willing to support a nested scrolling operation that is about to begin. If it returns true, this ViewParent will become the target view's nested scrolling parent for the duration of the scroll operation in progress. When the nested scroll is finished this ViewParent will receive a call to onStopNestedScroll(View, int).

      Parameters:
      child - Direct child of this ViewParent containing target
      target - View that initiated the nested scroll
      axes - Flags consisting of View.SCROLL_AXIS_HORIZONTAL, View.SCROLL_AXIS_VERTICAL or both
      type - the type of input which cause this scroll event
      Returns:
      true if this ViewParent accepts the nested scroll operation

    • onNestedScrollAccepted

      void onNestedScrollAccepted(@NonNull View child, @NonNull View target, int axes, int type)
      React to the successful claiming of a nested scroll operation.

      This method will be called after onStartNestedScroll returns true. It offers an opportunity for the view and its superclasses to perform initial configuration for the nested scroll. Implementations of this method should always call their superclasses' implementation of this method if one is present.

      Parameters:
      child - Direct child of this ViewParent containing target
      target - View that initiated the nested scroll
      axes - Flags consisting of View.SCROLL_AXIS_HORIZONTAL, View.SCROLL_AXIS_VERTICAL or both
      type - the type of input which cause this scroll event
      See Also:

    • onStopNestedScroll

      void onStopNestedScroll(@NonNull View target, int type)
      React to a nested scroll operation ending.

      Perform cleanup after a nested scrolling operation. This method will be called when a nested scroll stops, for example when a nested touch scroll ends with a MotionEvent.ACTION_UP or MotionEvent.ACTION_CANCEL event. Implementations of this method should always call their superclasses' implementation of this method if one is present.

      Parameters:
      target - View that initiated the nested scroll
      type - the type of input which cause this scroll event

    • onNestedScroll

      void onNestedScroll(@NonNull View target, int dxConsumed, int dyConsumed, int dxUnconsumed, int dyUnconsumed, int type, @NonNull int[] consumed)
      React to a nested scroll in progress.

      This method will be called when the ViewParent's current nested scrolling child view dispatches a nested scroll event. To receive calls to this method the ViewParent must have previously returned true for a call to onStartNestedScroll(View, View, int, int).

      Both the consumed and unconsumed portions of the scroll distance are reported to the ViewParent. An implementation may choose to use the consumed portion to match or chase scroll position of multiple child elements, for example. The unconsumed portion may be used to allow continuous dragging of multiple scrolling or draggable elements, such as scrolling a list within a vertical drawer where the drawer begins dragging once the edge of inner scrolling content is reached.

      This method is called when a nested scrolling child invokes View.dispatchNestedScroll(int, int, int, int, int[], int, int[])} or one of methods it overloads.

      An implementation must report how many pixels of the x and y scroll distances were consumed by this nested scrolling parent by adding the consumed distances to the consumed parameter. consumed should also be passed up to it's nested scrolling parent so that the parent may also add any scroll distance it consumes. Index 0 corresponds to dx and index 1 corresponds to dy.

      Parameters:
      target - The descendant view controlling the nested scroll
      dxConsumed - Horizontal scroll distance in pixels already consumed by target
      dyConsumed - Vertical scroll distance in pixels already consumed by target
      dxUnconsumed - Horizontal scroll distance in pixels not consumed by target
      dyUnconsumed - Vertical scroll distance in pixels not consumed by target
      type - the type of input which cause this scroll event
      consumed - Output. Upon this method returning, will contain the scroll distances consumed by this nested scrolling parent and the scroll distances consumed by any other parent up the view hierarchy
      See Also:

    • onNestedPreScroll

      void onNestedPreScroll(@NonNull View target, int dx, int dy, @NonNull int[] consumed, int type)
      React to a nested scroll in progress before the target view consumes a portion of the scroll.

      When working with nested scrolling often the parent view may want an opportunity to consume the scroll before the nested scrolling child does. An example of this is a drawer that contains a scrollable list. The user will want to be able to scroll the list fully into view before the list itself begins scrolling.

      onNestedPreScroll is called when a nested scrolling child invokes View.dispatchNestedPreScroll(int, int, int[], int[], int). The implementation should report how any pixels of the scroll reported by dx, dy were consumed in the consumed array. Index 0 corresponds to dx and index 1 corresponds to dy. This parameter will never be null. Initial values for consumed[0] and consumed[1] will always be 0.

      Parameters:
      target - View that initiated the nested scroll
      dx - Horizontal scroll distance in pixels
      dy - Vertical scroll distance in pixels
      consumed - Output. The horizontal and vertical scroll distance consumed by this parent
      type - the type of input which cause this scroll event

    • onNestedFling

      boolean onNestedFling(@NonNull View target, float velocityX, float velocityY, boolean consumed)
      Request a fling from a nested scroll.

      This method signifies that a nested scrolling child has detected suitable conditions for a fling. Generally this means that a touch scroll has ended with a velocity in the direction of scrolling that meets or exceeds the minimum fling velocity along a scrollable axis.

      If a nested scrolling child view would normally fling but it is at the edge of its own content, it can use this method to delegate the fling to its nested scrolling parent instead. The parent may optionally consume the fling or observe a child fling.

      Parameters:
      target - View that initiated the nested scroll
      velocityX - Horizontal velocity in pixels per second
      velocityY - Vertical velocity in pixels per second
      consumed - true if the child consumed the fling, false otherwise
      Returns:
      true if this parent consumed or otherwise reacted to the fling

    • onNestedPreFling

      boolean onNestedPreFling(@NonNull View target, float velocityX, float velocityY)
      React to a nested fling before the target view consumes it.

      This method signifies that a nested scrolling child has detected a fling with the given velocity along each axis. Generally this means that a touch scroll has ended with a velocity in the direction of scrolling that meets or exceeds the minimum fling velocity along a scrollable axis.

      If a nested scrolling parent is consuming motion as part of a pre-scroll, it may be appropriate for it to also consume the pre-fling to complete that same motion. By returning true from this method, the parent indicates that the child should not fling its own internal content as well.

      Parameters:
      target - View that initiated the nested scroll
      velocityX - Horizontal velocity in pixels per second
      velocityY - Vertical velocity in pixels per second
      Returns:
      true if this parent consumed the fling ahead of the target view

    • getNestedScrollAxes

      int getNestedScrollAxes()
      Return the current axes of nested scrolling for this NestedScrollingParent.

      A NestedScrollingParent returning something other than View.SCROLL_AXIS_NONE is currently acting as a nested scrolling parent for one or more descendant views in the hierarchy.

      Returns:
      Flags indicating the current axes of nested scrolling
      See Also: