| /* |
| * Copyright (C) 2011 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.support.v4.view; |
| |
| import android.os.Build; |
| import android.view.View; |
| import android.view.ViewGroup; |
| import android.view.accessibility.AccessibilityEvent; |
| |
| /** |
| * Helper for accessing features in {@link ViewGroup} |
| * introduced after API level 4 in a backwards compatible fashion. |
| */ |
| public class ViewGroupCompat { |
| |
| /** |
| * This constant is a {@link #setLayoutMode(ViewGroup, int) layoutMode}. |
| * Clip bounds are the raw values of {@link android.view.View#getLeft() left}, |
| * {@link android.view.View#getTop() top}, |
| * {@link android.view.View#getRight() right} and {@link android.view.View#getBottom() bottom}. |
| */ |
| public static final int LAYOUT_MODE_CLIP_BOUNDS = 0; |
| |
| /** |
| * This constant is a {@link #setLayoutMode(ViewGroup, int) layoutMode}. |
| * Optical bounds describe where a widget appears to be. They sit inside the clip |
| * bounds which need to cover a larger area to allow other effects, |
| * such as shadows and glows, to be drawn. |
| */ |
| public static final int LAYOUT_MODE_OPTICAL_BOUNDS = 1; |
| |
| interface ViewGroupCompatImpl { |
| boolean onRequestSendAccessibilityEvent(ViewGroup group, View child, |
| AccessibilityEvent event); |
| void setMotionEventSplittingEnabled(ViewGroup group, boolean split); |
| int getLayoutMode(ViewGroup group); |
| void setLayoutMode(ViewGroup group, int mode); |
| void setTransitionGroup(ViewGroup group, boolean isTransitionGroup); |
| boolean isTransitionGroup(ViewGroup group); |
| int getNestedScrollAxes(ViewGroup group); |
| } |
| |
| static class ViewGroupCompatStubImpl implements ViewGroupCompatImpl { |
| public boolean onRequestSendAccessibilityEvent( |
| ViewGroup group, View child, AccessibilityEvent event) { |
| return true; |
| } |
| |
| public void setMotionEventSplittingEnabled(ViewGroup group, boolean split) { |
| // no-op, didn't exist. |
| } |
| |
| @Override |
| public int getLayoutMode(ViewGroup group) { |
| return LAYOUT_MODE_CLIP_BOUNDS; |
| } |
| |
| @Override |
| public void setLayoutMode(ViewGroup group, int mode) { |
| // no-op, didn't exist. Views only support clip bounds. |
| } |
| |
| @Override |
| public void setTransitionGroup(ViewGroup group, boolean isTransitionGroup) { |
| } |
| |
| @Override |
| public boolean isTransitionGroup(ViewGroup group) { |
| return false; |
| } |
| |
| @Override |
| public int getNestedScrollAxes(ViewGroup group) { |
| if (group instanceof NestedScrollingParent) { |
| return ((NestedScrollingParent) group).getNestedScrollAxes(); |
| } |
| return ViewCompat.SCROLL_AXIS_NONE; |
| } |
| } |
| |
| static class ViewGroupCompatHCImpl extends ViewGroupCompatStubImpl { |
| @Override |
| public void setMotionEventSplittingEnabled(ViewGroup group, boolean split) { |
| ViewGroupCompatHC.setMotionEventSplittingEnabled(group, split); |
| } |
| } |
| |
| static class ViewGroupCompatIcsImpl extends ViewGroupCompatHCImpl { |
| @Override |
| public boolean onRequestSendAccessibilityEvent( |
| ViewGroup group, View child, AccessibilityEvent event) { |
| return ViewGroupCompatIcs.onRequestSendAccessibilityEvent(group, child, event); |
| } |
| } |
| |
| static class ViewGroupCompatJellybeanMR2Impl extends ViewGroupCompatIcsImpl { |
| @Override |
| public int getLayoutMode(ViewGroup group) { |
| return ViewGroupCompatJellybeanMR2.getLayoutMode(group); |
| } |
| |
| @Override |
| public void setLayoutMode(ViewGroup group, int mode) { |
| ViewGroupCompatJellybeanMR2.setLayoutMode(group, mode); |
| } |
| } |
| |
| static class ViewGroupCompatLollipopImpl extends ViewGroupCompatJellybeanMR2Impl { |
| @Override |
| public void setTransitionGroup(ViewGroup group, boolean isTransitionGroup) { |
| ViewGroupCompatLollipop.setTransitionGroup(group, isTransitionGroup); |
| } |
| |
| @Override |
| public boolean isTransitionGroup(ViewGroup group) { |
| return ViewGroupCompatLollipop.isTransitionGroup(group); |
| } |
| |
| @Override |
| public int getNestedScrollAxes(ViewGroup group) { |
| return ViewGroupCompatLollipop.getNestedScrollAxes(group); |
| } |
| } |
| |
| static final ViewGroupCompatImpl IMPL; |
| static { |
| final int version = Build.VERSION.SDK_INT; |
| if (version >= 21) { |
| IMPL = new ViewGroupCompatLollipopImpl(); |
| } else if (version >= 18) { |
| IMPL = new ViewGroupCompatJellybeanMR2Impl(); |
| } else if (version >= 14) { |
| IMPL = new ViewGroupCompatIcsImpl(); |
| } else if (version >= 11) { |
| IMPL = new ViewGroupCompatHCImpl(); |
| } else { |
| IMPL = new ViewGroupCompatStubImpl(); |
| } |
| } |
| |
| /* |
| * Hide the constructor. |
| */ |
| private ViewGroupCompat() { |
| |
| } |
| |
| /** |
| * Called when a child has requested sending an {@link AccessibilityEvent} and |
| * gives an opportunity to its parent to augment the event. |
| * <p> |
| * If an {@link AccessibilityDelegateCompat} has been specified via calling |
| * {@link ViewCompat#setAccessibilityDelegate(View, AccessibilityDelegateCompat)} its |
| * {@link AccessibilityDelegateCompat#onRequestSendAccessibilityEvent(ViewGroup, View, |
| * AccessibilityEvent)} is responsible for handling this call. |
| * </p> |
| * |
| * @param group The group whose method to invoke. |
| * @param child The child which requests sending the event. |
| * @param event The event to be sent. |
| * @return True if the event should be sent. |
| */ |
| public static boolean onRequestSendAccessibilityEvent(ViewGroup group, View child, |
| AccessibilityEvent event) { |
| return IMPL.onRequestSendAccessibilityEvent(group, child, event); |
| } |
| |
| /** |
| * Enable or disable the splitting of MotionEvents to multiple children during touch event |
| * dispatch. This behavior is enabled by default for applications that target an |
| * SDK version of 11 (Honeycomb) or newer. On earlier platform versions this feature |
| * was not supported and this method is a no-op. |
| * |
| * <p>When this option is enabled MotionEvents may be split and dispatched to different child |
| * views depending on where each pointer initially went down. This allows for user interactions |
| * such as scrolling two panes of content independently, chording of buttons, and performing |
| * independent gestures on different pieces of content. |
| * |
| * @param group ViewGroup to modify |
| * @param split <code>true</code> to allow MotionEvents to be split and dispatched to multiple |
| * child views. <code>false</code> to only allow one child view to be the target of |
| * any MotionEvent received by this ViewGroup. |
| */ |
| public static void setMotionEventSplittingEnabled(ViewGroup group, boolean split) { |
| IMPL.setMotionEventSplittingEnabled(group, split); |
| } |
| |
| /** |
| * Returns the basis of alignment during layout operations on this ViewGroup: |
| * either {@link #LAYOUT_MODE_CLIP_BOUNDS} or {@link #LAYOUT_MODE_OPTICAL_BOUNDS}. |
| * <p> |
| * If no layoutMode was explicitly set, either programmatically or in an XML resource, |
| * the method returns the layoutMode of the view's parent ViewGroup if such a parent exists, |
| * otherwise the method returns a default value of {@link #LAYOUT_MODE_CLIP_BOUNDS}. |
| * |
| * @return the layout mode to use during layout operations |
| * |
| * @see #setLayoutMode(ViewGroup, int) |
| */ |
| public static int getLayoutMode(ViewGroup group) { |
| return IMPL.getLayoutMode(group); |
| } |
| |
| /** |
| * Sets the basis of alignment during the layout of this ViewGroup. |
| * Valid values are either {@link #LAYOUT_MODE_CLIP_BOUNDS} or |
| * {@link #LAYOUT_MODE_OPTICAL_BOUNDS}. |
| * |
| * @param mode the layout mode to use during layout operations |
| * |
| * @see #getLayoutMode(ViewGroup) |
| */ |
| public static void setLayoutMode(ViewGroup group, int mode) { |
| IMPL.setLayoutMode(group, mode); |
| } |
| |
| /** |
| * Changes whether or not this ViewGroup should be treated as a single entity during |
| * Activity Transitions. |
| * @param isTransitionGroup Whether or not the ViewGroup should be treated as a unit |
| * in Activity transitions. If false, the ViewGroup won't transition, |
| * only its children. If true, the entire ViewGroup will transition |
| * together. |
| */ |
| public static void setTransitionGroup(ViewGroup group, boolean isTransitionGroup) { |
| IMPL.setTransitionGroup(group, isTransitionGroup); |
| } |
| |
| /** |
| * Returns true if this ViewGroup should be considered as a single entity for removal |
| * when executing an Activity transition. If this is false, child elements will move |
| * individually during the transition. |
| */ |
| public static boolean isTransitionGroup(ViewGroup group) { |
| return IMPL.isTransitionGroup(group); |
| } |
| |
| /** |
| * Return the current axes of nested scrolling for this ViewGroup. |
| * |
| * <p>A ViewGroup returning something other than {@link ViewCompat#SCROLL_AXIS_NONE} is |
| * currently acting as a nested scrolling parent for one or more descendant views in |
| * the hierarchy.</p> |
| * |
| * @return Flags indicating the current axes of nested scrolling |
| * @see ViewCompat#SCROLL_AXIS_HORIZONTAL |
| * @see ViewCompat#SCROLL_AXIS_VERTICAL |
| * @see ViewCompat#SCROLL_AXIS_NONE |
| */ |
| public static int getNestedScrollAxes(ViewGroup group) { |
| return IMPL.getNestedScrollAxes(group); |
| } |
| } |