| /* |
| * 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.widget; |
| |
| import android.content.Context; |
| import android.graphics.Canvas; |
| import android.os.Build; |
| |
| /** |
| * Helper for accessing {@link android.widget.EdgeEffect} introduced after |
| * API level 4 in a backwards compatible fashion. |
| * |
| * This class is used to access {@link android.widget.EdgeEffect} on platform versions |
| * that support it. When running on older platforms it will result in no-ops. It should |
| * be used by views that wish to use the standard Android visual effects at the edges |
| * of scrolling containers. |
| */ |
| public class EdgeEffectCompat { |
| private Object mEdgeEffect; |
| |
| private static final EdgeEffectImpl IMPL; |
| |
| static { |
| if (Build.VERSION.SDK_INT >= 21) { |
| IMPL = new EdgeEffectLollipopImpl(); // Lollipop |
| } else if (Build.VERSION.SDK_INT >= 14) { // ICS |
| IMPL = new EdgeEffectIcsImpl(); |
| } else { |
| IMPL = new BaseEdgeEffectImpl(); |
| } |
| } |
| |
| interface EdgeEffectImpl { |
| public Object newEdgeEffect(Context context); |
| public void setSize(Object edgeEffect, int width, int height); |
| public boolean isFinished(Object edgeEffect); |
| public void finish(Object edgeEffect); |
| public boolean onPull(Object edgeEffect, float deltaDistance); |
| public boolean onRelease(Object edgeEffect); |
| public boolean onAbsorb(Object edgeEffect, int velocity); |
| public boolean draw(Object edgeEffect, Canvas canvas); |
| public boolean onPull(Object edgeEffect, float deltaDistance, float displacement); |
| } |
| |
| /** |
| * Null implementation to use pre-ICS |
| */ |
| static class BaseEdgeEffectImpl implements EdgeEffectImpl { |
| public Object newEdgeEffect(Context context) { |
| return null; |
| } |
| |
| public void setSize(Object edgeEffect, int width, int height) { |
| } |
| |
| public boolean isFinished(Object edgeEffect) { |
| return true; |
| } |
| |
| public void finish(Object edgeEffect) { |
| } |
| |
| public boolean onPull(Object edgeEffect, float deltaDistance) { |
| return false; |
| } |
| |
| public boolean onRelease(Object edgeEffect) { |
| return false; |
| } |
| |
| public boolean onAbsorb(Object edgeEffect, int velocity) { |
| return false; |
| } |
| |
| public boolean draw(Object edgeEffect, Canvas canvas) { |
| return false; |
| } |
| |
| public boolean onPull(Object edgeEffect, float deltaDistance, float displacement) { |
| return false; |
| } |
| } |
| |
| static class EdgeEffectIcsImpl implements EdgeEffectImpl { |
| public Object newEdgeEffect(Context context) { |
| return EdgeEffectCompatIcs.newEdgeEffect(context); |
| } |
| |
| public void setSize(Object edgeEffect, int width, int height) { |
| EdgeEffectCompatIcs.setSize(edgeEffect, width, height); |
| } |
| |
| public boolean isFinished(Object edgeEffect) { |
| return EdgeEffectCompatIcs.isFinished(edgeEffect); |
| } |
| |
| public void finish(Object edgeEffect) { |
| EdgeEffectCompatIcs.finish(edgeEffect); |
| } |
| |
| public boolean onPull(Object edgeEffect, float deltaDistance) { |
| return EdgeEffectCompatIcs.onPull(edgeEffect, deltaDistance); |
| } |
| |
| public boolean onRelease(Object edgeEffect) { |
| return EdgeEffectCompatIcs.onRelease(edgeEffect); |
| } |
| |
| public boolean onAbsorb(Object edgeEffect, int velocity) { |
| return EdgeEffectCompatIcs.onAbsorb(edgeEffect, velocity); |
| } |
| |
| public boolean draw(Object edgeEffect, Canvas canvas) { |
| return EdgeEffectCompatIcs.draw(edgeEffect, canvas); |
| } |
| |
| public boolean onPull(Object edgeEffect, float deltaDistance, float displacement) { |
| return EdgeEffectCompatIcs.onPull(edgeEffect, deltaDistance); |
| } |
| } |
| |
| static class EdgeEffectLollipopImpl extends EdgeEffectIcsImpl { |
| public boolean onPull(Object edgeEffect, float deltaDistance, float displacement) { |
| return EdgeEffectCompatLollipop.onPull(edgeEffect, deltaDistance, displacement); |
| } |
| } |
| |
| /** |
| * Construct a new EdgeEffect themed using the given context. |
| * |
| * <p>Note: On platform versions that do not support EdgeEffect, all operations |
| * on the newly constructed object will be mocked/no-ops.</p> |
| * |
| * @param context Context to use for theming the effect |
| */ |
| public EdgeEffectCompat(Context context) { |
| mEdgeEffect = IMPL.newEdgeEffect(context); |
| } |
| |
| /** |
| * Set the size of this edge effect in pixels. |
| * |
| * @param width Effect width in pixels |
| * @param height Effect height in pixels |
| */ |
| public void setSize(int width, int height) { |
| IMPL.setSize(mEdgeEffect, width, height); |
| } |
| |
| /** |
| * Reports if this EdgeEffectCompat's animation is finished. If this method returns false |
| * after a call to {@link #draw(Canvas)} the host widget should schedule another |
| * drawing pass to continue the animation. |
| * |
| * @return true if animation is finished, false if drawing should continue on the next frame. |
| */ |
| public boolean isFinished() { |
| return IMPL.isFinished(mEdgeEffect); |
| } |
| |
| /** |
| * Immediately finish the current animation. |
| * After this call {@link #isFinished()} will return true. |
| */ |
| public void finish() { |
| IMPL.finish(mEdgeEffect); |
| } |
| |
| /** |
| * A view should call this when content is pulled away from an edge by the user. |
| * This will update the state of the current visual effect and its associated animation. |
| * The host view should always {@link android.view.View#invalidate()} if this method |
| * returns true and draw the results accordingly. |
| * |
| * @param deltaDistance Change in distance since the last call. Values may be 0 (no change) to |
| * 1.f (full length of the view) or negative values to express change |
| * back toward the edge reached to initiate the effect. |
| * @return true if the host view should call invalidate, false if it should not. |
| * @deprecated use {@link #onPull(float, float)} |
| */ |
| public boolean onPull(float deltaDistance) { |
| return IMPL.onPull(mEdgeEffect, deltaDistance); |
| } |
| |
| /** |
| * A view should call this when content is pulled away from an edge by the user. |
| * This will update the state of the current visual effect and its associated animation. |
| * The host view should always {@link android.view.View#invalidate()} if this method |
| * returns true and draw the results accordingly. |
| * |
| * @param deltaDistance Change in distance since the last call. Values may be 0 (no change) to |
| * 1.f (full length of the view) or negative values to express change |
| * back toward the edge reached to initiate the effect. |
| * @param displacement The displacement from the starting side of the effect of the point |
| * initiating the pull. In the case of touch this is the finger position. |
| * Values may be from 0-1. |
| * @return true if the host view should call invalidate, false if it should not. |
| */ |
| public boolean onPull(float deltaDistance, float displacement) { |
| return IMPL.onPull(mEdgeEffect, deltaDistance, displacement); |
| } |
| |
| /** |
| * Call when the object is released after being pulled. |
| * This will begin the "decay" phase of the effect. After calling this method |
| * the host view should {@link android.view.View#invalidate()} if this method |
| * returns true and thereby draw the results accordingly. |
| * |
| * @return true if the host view should invalidate, false if it should not. |
| */ |
| public boolean onRelease() { |
| return IMPL.onRelease(mEdgeEffect); |
| } |
| |
| /** |
| * Call when the effect absorbs an impact at the given velocity. |
| * Used when a fling reaches the scroll boundary. |
| * |
| * <p>When using a {@link android.widget.Scroller} or {@link android.widget.OverScroller}, |
| * the method <code>getCurrVelocity</code> will provide a reasonable approximation |
| * to use here.</p> |
| * |
| * @param velocity Velocity at impact in pixels per second. |
| * @return true if the host view should invalidate, false if it should not. |
| */ |
| public boolean onAbsorb(int velocity) { |
| return IMPL.onAbsorb(mEdgeEffect, velocity); |
| } |
| |
| /** |
| * Draw into the provided canvas. Assumes that the canvas has been rotated |
| * accordingly and the size has been set. The effect will be drawn the full |
| * width of X=0 to X=width, beginning from Y=0 and extending to some factor < |
| * 1.f of height. |
| * |
| * @param canvas Canvas to draw into |
| * @return true if drawing should continue beyond this frame to continue the |
| * animation |
| */ |
| public boolean draw(Canvas canvas) { |
| return IMPL.draw(mEdgeEffect, canvas); |
| } |
| } |