EdgeEffect.java revision 1373a8eb581fe3c8e9a036e69042015f98a7e346
1637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell/* 2637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * Copyright (C) 2010 The Android Open Source Project 3637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * 4637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * Licensed under the Apache License, Version 2.0 (the "License"); 5637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * you may not use this file except in compliance with the License. 6637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * You may obtain a copy of the License at 7637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * 8637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * http://www.apache.org/licenses/LICENSE-2.0 9637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * 10637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * Unless required by applicable law or agreed to in writing, software 11637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * distributed under the License is distributed on an "AS IS" BASIS, 12637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * See the License for the specific language governing permissions and 14637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * limitations under the License. 15637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell */ 16637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 17637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powellpackage android.widget; 18637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 1989935e41c593a599e8955388b27fb926e60e5e94Adam Powellimport com.android.internal.R; 2089935e41c593a599e8955388b27fb926e60e5e94Adam Powell 214e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereiraimport android.content.Context; 2289935e41c593a599e8955388b27fb926e60e5e94Adam Powellimport android.content.res.Resources; 23637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powellimport android.graphics.Canvas; 24637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powellimport android.graphics.drawable.Drawable; 25637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powellimport android.view.animation.AnimationUtils; 26637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powellimport android.view.animation.DecelerateInterpolator; 27637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powellimport android.view.animation.Interpolator; 28637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 29637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell/** 3089935e41c593a599e8955388b27fb926e60e5e94Adam Powell * This class performs the graphical effect used at the edges of scrollable widgets 3189935e41c593a599e8955388b27fb926e60e5e94Adam Powell * when the user scrolls beyond the content bounds in 2D space. 3289935e41c593a599e8955388b27fb926e60e5e94Adam Powell * 3389935e41c593a599e8955388b27fb926e60e5e94Adam Powell * <p>EdgeEffect is stateful. Custom widgets using EdgeEffect should create an 3489935e41c593a599e8955388b27fb926e60e5e94Adam Powell * instance for each edge that should show the effect, feed it input data using 3589935e41c593a599e8955388b27fb926e60e5e94Adam Powell * the methods {@link #onAbsorb(int)}, {@link #onPull(float)}, and {@link #onRelease()}, 3689935e41c593a599e8955388b27fb926e60e5e94Adam Powell * and draw the effect using {@link #draw(Canvas)} in the widget's overridden 3789935e41c593a599e8955388b27fb926e60e5e94Adam Powell * {@link android.view.View#draw(Canvas)} method. If {@link #isFinished()} returns 3889935e41c593a599e8955388b27fb926e60e5e94Adam Powell * false after drawing, the edge effect's animation is not yet complete and the widget 3989935e41c593a599e8955388b27fb926e60e5e94Adam Powell * should schedule another drawing pass to continue the animation.</p> 4089935e41c593a599e8955388b27fb926e60e5e94Adam Powell * 4189935e41c593a599e8955388b27fb926e60e5e94Adam Powell * <p>When drawing, widgets should draw their main content and child views first, 4289935e41c593a599e8955388b27fb926e60e5e94Adam Powell * usually by invoking <code>super.draw(canvas)</code> from an overridden <code>draw</code> 4389935e41c593a599e8955388b27fb926e60e5e94Adam Powell * method. (This will invoke onDraw and dispatch drawing to child views as needed.) 4489935e41c593a599e8955388b27fb926e60e5e94Adam Powell * The edge effect may then be drawn on top of the view's content using the 4589935e41c593a599e8955388b27fb926e60e5e94Adam Powell * {@link #draw(Canvas)} method.</p> 46637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell */ 4789935e41c593a599e8955388b27fb926e60e5e94Adam Powellpublic class EdgeEffect { 4889935e41c593a599e8955388b27fb926e60e5e94Adam Powell private static final String TAG = "EdgeEffect"; 49637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 50637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Time it will take the effect to fully recede in ms 51637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int RECEDE_TIME = 1000; 52637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 5389935e41c593a599e8955388b27fb926e60e5e94Adam Powell // Time it will take before a pulled glow begins receding in ms 54637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int PULL_TIME = 167; 55637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 5689935e41c593a599e8955388b27fb926e60e5e94Adam Powell // Time it will take in ms for a pulled glow to decay to partial strength before release 57637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int PULL_DECAY_TIME = 1000; 58637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 59637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final float MAX_ALPHA = 0.8f; 60637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final float HELD_EDGE_ALPHA = 0.7f; 61637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final float HELD_EDGE_SCALE_Y = 0.5f; 62637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final float HELD_GLOW_ALPHA = 0.5f; 63637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final float HELD_GLOW_SCALE_Y = 0.5f; 64637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 654e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira private static final float MAX_GLOW_HEIGHT = 4.f; 66637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 67637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final float PULL_GLOW_BEGIN = 1.f; 68637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final float PULL_EDGE_BEGIN = 0.6f; 69637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 70637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Minimum velocity that will be absorbed 71637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int MIN_VELOCITY = 100; 72637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 73637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final float EPSILON = 0.001f; 74637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 75637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private final Drawable mEdge; 76637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private final Drawable mGlow; 77637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private int mWidth; 78637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private int mHeight; 794e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira private final int MIN_WIDTH = 300; 804e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira private final int mMinWidth; 81637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 82637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mEdgeAlpha; 83637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mEdgeScaleY; 84637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mGlowAlpha; 85637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mGlowScaleY; 86637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 87637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mEdgeAlphaStart; 88637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mEdgeAlphaFinish; 89637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mEdgeScaleYStart; 90637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mEdgeScaleYFinish; 91637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mGlowAlphaStart; 92637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mGlowAlphaFinish; 93637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mGlowScaleYStart; 94637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mGlowScaleYFinish; 95637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 96637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private long mStartTime; 97637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mDuration; 98637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 99637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private final Interpolator mInterpolator; 100637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 101637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int STATE_IDLE = 0; 102637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int STATE_PULL = 1; 103637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int STATE_ABSORB = 2; 104637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int STATE_RECEDE = 3; 105637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int STATE_PULL_DECAY = 4; 106637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 107637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // How much dragging should effect the height of the edge image. 108637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Number determined by user testing. 1094e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira private static final int PULL_DISTANCE_EDGE_FACTOR = 7; 110637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 111637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // How much dragging should effect the height of the glow image. 112637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Number determined by user testing. 1134e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira private static final int PULL_DISTANCE_GLOW_FACTOR = 7; 1144e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira private static final float PULL_DISTANCE_ALPHA_GLOW_FACTOR = 1.1f; 115637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 116637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int VELOCITY_EDGE_FACTOR = 8; 117637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private static final int VELOCITY_GLOW_FACTOR = 16; 118637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 119637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private int mState = STATE_IDLE; 120637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 121637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private float mPullDistance; 122637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 12389935e41c593a599e8955388b27fb926e60e5e94Adam Powell /** 12489935e41c593a599e8955388b27fb926e60e5e94Adam Powell * Construct a new EdgeEffect with a theme appropriate for the provided context. 12589935e41c593a599e8955388b27fb926e60e5e94Adam Powell * @param context Context used to provide theming and resource information for the EdgeEffect 12689935e41c593a599e8955388b27fb926e60e5e94Adam Powell */ 12789935e41c593a599e8955388b27fb926e60e5e94Adam Powell public EdgeEffect(Context context) { 12889935e41c593a599e8955388b27fb926e60e5e94Adam Powell final Resources res = context.getResources(); 12989935e41c593a599e8955388b27fb926e60e5e94Adam Powell mEdge = res.getDrawable(R.drawable.overscroll_edge); 13089935e41c593a599e8955388b27fb926e60e5e94Adam Powell mGlow = res.getDrawable(R.drawable.overscroll_glow); 131637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 1321373a8eb581fe3c8e9a036e69042015f98a7e346Christopher Tate mMinWidth = (int) (res.getDisplayMetrics().density * MIN_WIDTH + 0.5f); 133637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mInterpolator = new DecelerateInterpolator(); 134637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 135637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 13689935e41c593a599e8955388b27fb926e60e5e94Adam Powell /** 13789935e41c593a599e8955388b27fb926e60e5e94Adam Powell * Set the size of this edge effect in pixels. 13889935e41c593a599e8955388b27fb926e60e5e94Adam Powell * 13989935e41c593a599e8955388b27fb926e60e5e94Adam Powell * @param width Effect width in pixels 14089935e41c593a599e8955388b27fb926e60e5e94Adam Powell * @param height Effect height in pixels 14189935e41c593a599e8955388b27fb926e60e5e94Adam Powell */ 142637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell public void setSize(int width, int height) { 143637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mWidth = width; 144637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mHeight = height; 145637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 146637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 14789935e41c593a599e8955388b27fb926e60e5e94Adam Powell /** 14889935e41c593a599e8955388b27fb926e60e5e94Adam Powell * Reports if this EdgeEffect's animation is finished. If this method returns false 14989935e41c593a599e8955388b27fb926e60e5e94Adam Powell * after a call to {@link #draw(Canvas)} the host widget should schedule another 15089935e41c593a599e8955388b27fb926e60e5e94Adam Powell * drawing pass to continue the animation. 15189935e41c593a599e8955388b27fb926e60e5e94Adam Powell * 15289935e41c593a599e8955388b27fb926e60e5e94Adam Powell * @return true if animation is finished, false if drawing should continue on the next frame. 15389935e41c593a599e8955388b27fb926e60e5e94Adam Powell */ 154637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell public boolean isFinished() { 155637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell return mState == STATE_IDLE; 156637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 157637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 15889935e41c593a599e8955388b27fb926e60e5e94Adam Powell /** 15989935e41c593a599e8955388b27fb926e60e5e94Adam Powell * Immediately finish the current animation. 16089935e41c593a599e8955388b27fb926e60e5e94Adam Powell * After this call {@link #isFinished()} will return true. 16189935e41c593a599e8955388b27fb926e60e5e94Adam Powell */ 162637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell public void finish() { 163637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mState = STATE_IDLE; 164637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 165637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 166637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell /** 16789935e41c593a599e8955388b27fb926e60e5e94Adam Powell * A view should call this when content is pulled away from an edge by the user. 16889935e41c593a599e8955388b27fb926e60e5e94Adam Powell * This will update the state of the current visual effect and its associated animation. 16989935e41c593a599e8955388b27fb926e60e5e94Adam Powell * The host view should always {@link android.view.View#invalidate()} after this 17089935e41c593a599e8955388b27fb926e60e5e94Adam Powell * and draw the results accordingly. 171637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * 17289935e41c593a599e8955388b27fb926e60e5e94Adam Powell * @param deltaDistance Change in distance since the last call. Values may be 0 (no change) to 17389935e41c593a599e8955388b27fb926e60e5e94Adam Powell * 1.f (full length of the view) or negative values to express change 17489935e41c593a599e8955388b27fb926e60e5e94Adam Powell * back toward the edge reached to initiate the effect. 175637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell */ 176637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell public void onPull(float deltaDistance) { 177637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell final long now = AnimationUtils.currentAnimationTimeMillis(); 178637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell if (mState == STATE_PULL_DECAY && now - mStartTime < mDuration) { 179637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell return; 180637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 181637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell if (mState != STATE_PULL) { 182637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleY = PULL_GLOW_BEGIN; 183637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 184637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mState = STATE_PULL; 185637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 186637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mStartTime = now; 187637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mDuration = PULL_TIME; 188637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 189637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mPullDistance += deltaDistance; 190637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell float distance = Math.abs(mPullDistance); 191637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 192637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlpha = mEdgeAlphaStart = Math.max(PULL_EDGE_BEGIN, Math.min(distance, MAX_ALPHA)); 193637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleY = mEdgeScaleYStart = Math.max( 194637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell HELD_EDGE_SCALE_Y, Math.min(distance * PULL_DISTANCE_EDGE_FACTOR, 1.f)); 195637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 196637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlpha = mGlowAlphaStart = Math.min(MAX_ALPHA, 197637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlpha + 198637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell (Math.abs(deltaDistance) * PULL_DISTANCE_ALPHA_GLOW_FACTOR)); 199637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 200637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell float glowChange = Math.abs(deltaDistance); 201637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell if (deltaDistance > 0 && mPullDistance < 0) { 202637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell glowChange = -glowChange; 203637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 204637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell if (mPullDistance == 0) { 205637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleY = 0; 206637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 207637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 208637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Do not allow glow to get larger than MAX_GLOW_HEIGHT. 209637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleY = mGlowScaleYStart = Math.min(MAX_GLOW_HEIGHT, Math.max( 210637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 0, mGlowScaleY + glowChange * PULL_DISTANCE_GLOW_FACTOR)); 211637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 212637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaFinish = mEdgeAlpha; 213637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleYFinish = mEdgeScaleY; 214637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaFinish = mGlowAlpha; 215637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYFinish = mGlowScaleY; 216637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 217637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 218637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell /** 219637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * Call when the object is released after being pulled. 22089935e41c593a599e8955388b27fb926e60e5e94Adam Powell * This will begin the "decay" phase of the effect. After calling this method 22189935e41c593a599e8955388b27fb926e60e5e94Adam Powell * the host view should {@link android.view.View#invalidate()} and thereby 22289935e41c593a599e8955388b27fb926e60e5e94Adam Powell * draw the results accordingly. 223637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell */ 224637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell public void onRelease() { 225637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mPullDistance = 0; 226637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 227637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell if (mState != STATE_PULL && mState != STATE_PULL_DECAY) { 228637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell return; 229637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 230637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 231637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mState = STATE_RECEDE; 232637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaStart = mEdgeAlpha; 233637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleYStart = mEdgeScaleY; 234637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaStart = mGlowAlpha; 235637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYStart = mGlowScaleY; 236637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 237637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaFinish = 0.f; 238637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleYFinish = 0.f; 239637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaFinish = 0.f; 240637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYFinish = 0.f; 241637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 242637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mStartTime = AnimationUtils.currentAnimationTimeMillis(); 243637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mDuration = RECEDE_TIME; 244637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 245637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 246637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell /** 247637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * Call when the effect absorbs an impact at the given velocity. 24889935e41c593a599e8955388b27fb926e60e5e94Adam Powell * Used when a fling reaches the scroll boundary. 24989935e41c593a599e8955388b27fb926e60e5e94Adam Powell * 25089935e41c593a599e8955388b27fb926e60e5e94Adam Powell * <p>When using a {@link android.widget.Scroller} or {@link android.widget.OverScroller}, 25189935e41c593a599e8955388b27fb926e60e5e94Adam Powell * the method <code>getCurrVelocity</code> will provide a reasonable approximation 25289935e41c593a599e8955388b27fb926e60e5e94Adam Powell * to use here.</p> 253637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * 254637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * @param velocity Velocity at impact in pixels per second. 255637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell */ 256637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell public void onAbsorb(int velocity) { 257637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mState = STATE_ABSORB; 258637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell velocity = Math.max(MIN_VELOCITY, Math.abs(velocity)); 259637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 260637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mStartTime = AnimationUtils.currentAnimationTimeMillis(); 261637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mDuration = 0.1f + (velocity * 0.03f); 262637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 263637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // The edge should always be at least partially visible, regardless 264637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // of velocity. 265637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaStart = 0.f; 266637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleY = mEdgeScaleYStart = 0.f; 267637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // The glow depends more on the velocity, and therefore starts out 268637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // nearly invisible. 269637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaStart = 0.5f; 270637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYStart = 0.f; 271637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 272637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Factor the velocity by 8. Testing on device shows this works best to 273637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // reflect the strength of the user's scrolling. 274637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaFinish = Math.max(0, Math.min(velocity * VELOCITY_EDGE_FACTOR, 1)); 275637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Edge should never get larger than the size of its asset. 276637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleYFinish = Math.max( 277637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell HELD_EDGE_SCALE_Y, Math.min(velocity * VELOCITY_EDGE_FACTOR, 1.f)); 278637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 279637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Growth for the size of the glow should be quadratic to properly 280637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // respond 281637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // to a user's scrolling speed. The faster the scrolling speed, the more 282637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // intense the effect should be for both the size and the saturation. 283637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYFinish = Math.min(0.025f + (velocity * (velocity / 100) * 0.00015f), 1.75f); 284637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // Alpha should change for the glow as well as size. 285637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaFinish = Math.max( 286637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaStart, Math.min(velocity * VELOCITY_GLOW_FACTOR * .00001f, MAX_ALPHA)); 287637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 288637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 289637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 290637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell /** 291637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * Draw into the provided canvas. Assumes that the canvas has been rotated 292637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * accordingly and the size has been set. The effect will be drawn the full 29389935e41c593a599e8955388b27fb926e60e5e94Adam Powell * width of X=0 to X=width, beginning from Y=0 and extending to some factor < 294637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * 1.f of height. 295637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * 296637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * @param canvas Canvas to draw into 297637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * @return true if drawing should continue beyond this frame to continue the 298637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell * animation 299637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell */ 300637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell public boolean draw(Canvas canvas) { 301637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell update(); 302637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 303637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell final int edgeHeight = mEdge.getIntrinsicHeight(); 304a5531d784b9b79fe3bf9b30d99e9c99ea3947c6dMindy Pereira final int edgeWidth = mEdge.getIntrinsicWidth(); 305637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell final int glowHeight = mGlow.getIntrinsicHeight(); 306a5531d784b9b79fe3bf9b30d99e9c99ea3947c6dMindy Pereira final int glowWidth = mGlow.getIntrinsicWidth(); 307637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 308637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlow.setAlpha((int) (Math.max(0, Math.min(mGlowAlpha, 1)) * 255)); 309a5531d784b9b79fe3bf9b30d99e9c99ea3947c6dMindy Pereira 3104e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira int glowBottom = (int) Math.min( 311a5531d784b9b79fe3bf9b30d99e9c99ea3947c6dMindy Pereira glowHeight * mGlowScaleY * glowHeight/ glowWidth * 0.6f, 3124e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira glowHeight * MAX_GLOW_HEIGHT); 3134e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira if (mWidth < mMinWidth) { 3144e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira // Center the glow and clip it. 315ffc4196c46419469f088ca23a0d0e31cf7979e30Jim Miller int glowLeft = (mWidth - mMinWidth)/2; 3164e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira mGlow.setBounds(glowLeft, 0, mWidth - glowLeft, glowBottom); 3174e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira } else { 3184e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira // Stretch the glow to fit. 3194e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira mGlow.setBounds(0, 0, mWidth, glowBottom); 3204e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira } 3214e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira 322637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlow.draw(canvas); 323637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 324637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdge.setAlpha((int) (Math.max(0, Math.min(mEdgeAlpha, 1)) * 255)); 325a5531d784b9b79fe3bf9b30d99e9c99ea3947c6dMindy Pereira 3264e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira int edgeBottom = (int) (edgeHeight * mEdgeScaleY); 3274e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira if (mWidth < mMinWidth) { 3284e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira // Center the edge and clip it. 329ffc4196c46419469f088ca23a0d0e31cf7979e30Jim Miller int edgeLeft = (mWidth - mMinWidth)/2; 3304e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira mEdge.setBounds(edgeLeft, 0, mWidth - edgeLeft, edgeBottom); 3314e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira } else { 3324e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira // Stretch the edge to fit. 3334e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira mEdge.setBounds(0, 0, mWidth, edgeBottom); 3344e30d89ceda832300f80bf73f4f58cd2b51bf112Mindy Pereira } 335637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdge.draw(canvas); 336637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 337637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell return mState != STATE_IDLE; 338637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 339637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 340637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell private void update() { 341637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell final long time = AnimationUtils.currentAnimationTimeMillis(); 342637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell final float t = Math.min((time - mStartTime) / mDuration, 1.f); 343637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 344637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell final float interp = mInterpolator.getInterpolation(t); 345637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 346637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlpha = mEdgeAlphaStart + (mEdgeAlphaFinish - mEdgeAlphaStart) * interp; 347637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleY = mEdgeScaleYStart + (mEdgeScaleYFinish - mEdgeScaleYStart) * interp; 348637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlpha = mGlowAlphaStart + (mGlowAlphaFinish - mGlowAlphaStart) * interp; 349637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleY = mGlowScaleYStart + (mGlowScaleYFinish - mGlowScaleYStart) * interp; 350637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 351637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell if (t >= 1.f - EPSILON) { 352637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell switch (mState) { 353637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell case STATE_ABSORB: 354637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mState = STATE_RECEDE; 355637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mStartTime = AnimationUtils.currentAnimationTimeMillis(); 356637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mDuration = RECEDE_TIME; 357637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 358637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaStart = mEdgeAlpha; 359637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleYStart = mEdgeScaleY; 360637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaStart = mGlowAlpha; 361637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYStart = mGlowScaleY; 362637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 363637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // After absorb, the glow and edge should fade to nothing. 364637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaFinish = 0.f; 365637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleYFinish = 0.f; 366637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaFinish = 0.f; 367637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYFinish = 0.f; 368637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell break; 369637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell case STATE_PULL: 370637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mState = STATE_PULL_DECAY; 371637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mStartTime = AnimationUtils.currentAnimationTimeMillis(); 372637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mDuration = PULL_DECAY_TIME; 373637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 374637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaStart = mEdgeAlpha; 375637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleYStart = mEdgeScaleY; 376637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaStart = mGlowAlpha; 377637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYStart = mGlowScaleY; 378637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell 379637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // After pull, the glow and edge should fade to nothing. 380637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeAlphaFinish = 0.f; 381637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleYFinish = 0.f; 382637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowAlphaFinish = 0.f; 383637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mGlowScaleYFinish = 0.f; 384637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell break; 385637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell case STATE_PULL_DECAY: 386637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // When receding, we want edge to decrease more slowly 387637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell // than the glow. 388637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell float factor = mGlowScaleYFinish != 0 ? 1 389637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell / (mGlowScaleYFinish * mGlowScaleYFinish) 390637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell : Float.MAX_VALUE; 391637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mEdgeScaleY = mEdgeScaleYStart + 392637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell (mEdgeScaleYFinish - mEdgeScaleYStart) * 393637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell interp * factor; 3940b1ab3a2776a1fff5b2abbddd3bc256e355e30efDaniel Mladenovic mState = STATE_RECEDE; 395637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell break; 396637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell case STATE_RECEDE: 397637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell mState = STATE_IDLE; 398637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell break; 399637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 400637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 401637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell } 402637d337b58d8eec6de19230a5dd5ca5581c0478dAdam Powell} 403