/*
* Copyright (C) 2006 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.view;
import android.graphics.Rect;
import android.view.accessibility.AccessibilityEvent;
/**
* Defines the responsibilities for a class that will be a parent of a View.
* This is the API that a view sees when it wants to interact with its parent.
*
*/
public interface ViewParent {
/**
* 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.
*/
public void requestLayout();
/**
* Indicates whether layout was requested on this view parent.
*
* @return true if layout was requested, false otherwise
*/
public boolean isLayoutRequested();
/**
* Called when a child wants the view hierarchy to gather and report
* transparent regions to the window compositor. Views that "punch" holes in
* the view hierarchy, such as SurfaceView can use this API to improve
* performance of the system. When no such a view is present in the
* hierarchy, this optimization in unnecessary and might slightly reduce the
* view hierarchy performance.
*
* @param child the view requesting the transparent region computation
*
*/
public void requestTransparentRegion(View child);
/**
* All or part of a child is dirty and needs to be redrawn.
*
* @param child The child which is dirty
* @param r The area within the child that is invalid
*/
public void invalidateChild(View child, Rect r);
/**
* All or part of a child is dirty and needs to be redrawn.
*
* <p>The location array is an array of two int values which respectively
* define the left and the top position of the dirty child.</p>
*
* <p>This method must return the parent of this ViewParent if the specified
* rectangle must be invalidated in the parent. If the specified rectangle
* does not require invalidation in the parent or if the parent does not
* exist, this method must return null.</p>
*
* <p>When this method returns a non-null value, the location array must
* have been updated with the left and top coordinates of this ViewParent.</p>
*
* @param location An array of 2 ints containing the left and top
* coordinates of the child to invalidate
* @param r The area within the child that is invalid
*
* @return the parent of this ViewParent or null
*/
public ViewParent invalidateChildInParent(int[] location, Rect r);
/**
* Returns the parent if it exists, or null.
*
* @return a ViewParent or null if this ViewParent does not have a parent
*/
public ViewParent getParent();
/**
* Called when a child of this parent wants focus
*
* @param 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.
* @param focused The view that is a descendant of child that actually has
* focus
*/
public void requestChildFocus(View child, View focused);
/**
* Tell view hierarchy that the global view attributes need to be
* re-evaluated.
*
* @param child View whose attributes have changed.
*/
public void recomputeViewAttributes(View child);
/**
* Called when a child of this parent is giving up focus
*
* @param child The view that is giving up focus
*/
public void clearChildFocus(View child);
/**
* Compute the visible part of a rectangular region defined in terms of a child view's
* coordinates.
*
* <p>Returns the clipped visible part of the rectangle <code>r</code>, defined in the
* <code>child</code>'s local coordinate system. <code>r</code> is modified by this method to
* contain the result, expressed in the global (root) coordinate system.</p>
*
* <p>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.</p>
*
* @param child A child View, whose rectangular visible region we want to compute
* @param r The input rectangle, defined in the child coordinate system. Will be overwritten to
* contain the resulting visible rectangle, expressed in global (root) coordinates
* @param offset The input coordinates of a point, defined in the child coordinate system.
* As with the <code>r</code> parameter, this will be overwritten to contain the global (root)
* coordinates of that point.
* A <code>null</code> value is valid (in case you are not interested in this result)
* @return true if the resulting rectangle is not empty, false otherwise
*/
public boolean getChildVisibleRect(View child, Rect r, android.graphics.Point offset);
/**
* Find the nearest view in the specified direction that wants to take focus
*
* @param v The view that currently has focus
* @param direction One of FOCUS_UP, FOCUS_DOWN, FOCUS_LEFT, and FOCUS_RIGHT
*/
public View focusSearch(View v, int direction);
/**
* Change the z order of the child so it's on top of all other children
*
* @param child
*/
public void bringChildToFront(View child);
/**
* 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.
*
* @param v The view that has become newly focusable
*/
public void focusableViewAvailable(View v);
/**
* Bring up a context menu for the specified view or its ancestors.
*
* <p>In most cases, a subclass does not need to override this. However, if
* the subclass is added directly to the window manager (for example,
* {@link ViewManager#addView(View, android.view.ViewGroup.LayoutParams)})
* then it should override this and show the context menu.</p>
*
* @param originalView The source view where the context menu was first invoked
* @return true if a context menu was displayed
*/
public boolean showContextMenuForChild(View originalView);
/**
* Have the parent populate the specified context menu if it has anything to
* add (and then recurse on its parent).
*
* @param menu The menu to populate
*/
public void createContextMenu(ContextMenu menu);
/**
* Start an action mode for the specified view.
*
* <p>In most cases, a subclass does not need to override this. However, if the
* subclass is added directly to the window manager (for example,
* {@link ViewManager#addView(View, android.view.ViewGroup.LayoutParams)})
* then it should override this and start the action mode.</p>
*
* @param originalView The source view where the action mode was first invoked
* @param callback The callback that will handle lifecycle events for the action mode
* @return The new action mode if it was started, null otherwise
*/
public ActionMode startActionModeForChild(View originalView, ActionMode.Callback callback);
/**
* This method is called on the parent when a child's drawable state
* has changed.
*
* @param child The child whose drawable state has changed.
*/
public void childDrawableStateChanged(View child);
/**
* Called when a child does not want this parent and its ancestors to
* intercept touch events with
* {@link ViewGroup#onInterceptTouchEvent(MotionEvent)}.
*
* <p>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.</p>
*
* @param disallowIntercept True if the child does not want the parent to
* intercept touch events.
*/
public void requestDisallowInterceptTouchEvent(boolean disallowIntercept);
/**
* Called when a child of this group wants a particular rectangle to be
* positioned onto the screen. {@link ViewGroup}s overriding this can trust
* that:
* <ul>
* <li>child will be a direct child of this group</li>
* <li>rectangle will be in the child's coordinates</li>
* </ul>
*
* <p>{@link ViewGroup}s overriding this should uphold the contract:</p>
* <ul>
* <li>nothing will change if the rectangle is already visible</li>
* <li>the view port will be scrolled only just enough to make the
* rectangle visible</li>
* <ul>
*
* @param child The direct child making the request.
* @param rectangle The rectangle in the child's coordinates the child
* wishes to be on the screen.
* @param immediate True to forbid animated or delayed scrolling,
* false otherwise
* @return Whether the group scrolled to handle the operation
*/
public boolean requestChildRectangleOnScreen(View child, Rect rectangle,
boolean immediate);
/**
* Called by a child to request from its parent to send an {@link AccessibilityEvent}.
* The child has already populated a record for itself in the event and is delegating
* to its parent to send the event. The parent can optionally add a record for itself.
* <p>
* Note: An accessibility event is fired by an individual view which populates the
* event with a record for its state and requests from its parent to perform
* the sending. The parent can optionally add a record for itself before
* dispatching the request to its parent. A parent can also choose not to
* respect the request for sending the event. The accessibility event is sent
* by the topmost view in the view tree.</p>
*
* @param child The child which requests sending the event.
* @param event The event to be sent.
* @return True if the event was sent.
*/
public boolean requestSendAccessibilityEvent(View child, AccessibilityEvent event);
/**
* Called when a child view now has or no longer is tracking transient state.
*
* @param child Child view whose state has changed
* @param hasTransientState true if this child has transient state
*
* @hide
*/
public void childHasTransientStateChanged(View child, boolean hasTransientState);
/**
* Ask that a new dispatch of {@link View#fitSystemWindows(Rect)
* View.fitSystemWindows(Rect)} be performed.
*/
public void requestFitSystemWindows();
/**
* Gets the parent of a given View for accessibility. Since some Views are not
* exposed to the accessibility layer the parent for accessibility is not
* necessarily the direct parent of the View, rather it is a predecessor.
*
* @return The parent or <code>null</code> if no such is found.
*/
public ViewParent getParentForAccessibility();
/**
* A child notifies its parent that its state for accessibility has changed.
* That is some of the child properties reported to accessibility services has
* changed, hence the interested services have to be notified for the new state.
*
* @hide
*/
public void childAccessibilityStateChanged(View child);
}