Java tutorial
/* -*- Mode: Java; c-basic-offset: 4; tab-width: 20; indent-tabs-mode: nil; -*- /* This Source Code Form is subject to the terms of the Mozilla Public * License, v. 2.0. If a copy of the MPL was not distributed with this file, * You can obtain one at http://mozilla.org/MPL/2.0/. */ package org.mozilla.gecko.animation; import java.util.ArrayList; import java.util.List; import org.mozilla.gecko.AppConstants.Versions; import android.os.Handler; import android.support.v4.view.ViewCompat; import android.view.Choreographer; import android.view.View; import android.view.ViewGroup; import android.view.ViewTreeObserver; import android.view.animation.AnimationUtils; import android.view.animation.DecelerateInterpolator; import android.view.animation.Interpolator; public class PropertyAnimator implements Runnable { private static final String LOGTAG = "GeckoPropertyAnimator"; public static enum Property { ALPHA, TRANSLATION_X, TRANSLATION_Y, SCROLL_X, SCROLL_Y, WIDTH, HEIGHT } private class ElementHolder { View view; AnimatorProxy proxy; Property property; float from; float to; } public static interface PropertyAnimationListener { public void onPropertyAnimationStart(); public void onPropertyAnimationEnd(); } private final Interpolator mInterpolator; private long mStartTime; private final long mDuration; private final float mDurationReciprocal; private final List<ElementHolder> mElementsList; private List<PropertyAnimationListener> mListeners; FramePoster mFramePoster; private boolean mUseHardwareLayer; public PropertyAnimator(long duration) { this(duration, new DecelerateInterpolator()); } public PropertyAnimator(long duration, Interpolator interpolator) { mDuration = duration; mDurationReciprocal = 1.0f / mDuration; mInterpolator = interpolator; mElementsList = new ArrayList<ElementHolder>(); mFramePoster = FramePoster.create(this); mUseHardwareLayer = true; } public void setUseHardwareLayer(boolean useHardwareLayer) { mUseHardwareLayer = useHardwareLayer; } public void attach(View view, Property property, float to) { ElementHolder element = new ElementHolder(); element.view = view; element.proxy = AnimatorProxy.create(view); element.property = property; element.to = to; mElementsList.add(element); } public void addPropertyAnimationListener(PropertyAnimationListener listener) { if (mListeners == null) { mListeners = new ArrayList<PropertyAnimationListener>(); } mListeners.add(listener); } public long getDuration() { return mDuration; } public long getRemainingTime() { int timePassed = (int) (AnimationUtils.currentAnimationTimeMillis() - mStartTime); return mDuration - timePassed; } @Override public void run() { int timePassed = (int) (AnimationUtils.currentAnimationTimeMillis() - mStartTime); if (timePassed >= mDuration) { stop(); return; } float interpolation = mInterpolator.getInterpolation(timePassed * mDurationReciprocal); for (ElementHolder element : mElementsList) { float delta = element.from + ((element.to - element.from) * interpolation); invalidate(element, delta); } mFramePoster.postNextAnimationFrame(); } public void start() { if (mDuration == 0) { return; } mStartTime = AnimationUtils.currentAnimationTimeMillis(); // Fix the from value based on current position and property for (ElementHolder element : mElementsList) { if (element.property == Property.ALPHA) element.from = element.proxy.getAlpha(); else if (element.property == Property.TRANSLATION_Y) element.from = element.proxy.getTranslationY(); else if (element.property == Property.TRANSLATION_X) element.from = element.proxy.getTranslationX(); else if (element.property == Property.SCROLL_Y) element.from = element.proxy.getScrollY(); else if (element.property == Property.SCROLL_X) element.from = element.proxy.getScrollX(); else if (element.property == Property.WIDTH) element.from = element.proxy.getWidth(); else if (element.property == Property.HEIGHT) element.from = element.proxy.getHeight(); ViewCompat.setHasTransientState(element.view, true); if (shouldEnableHardwareLayer(element)) element.view.setLayerType(View.LAYER_TYPE_HARDWARE, null); else element.view.setDrawingCacheEnabled(true); } // Get ViewTreeObserver from any of the participant views // in the animation. final ViewTreeObserver treeObserver; if (mElementsList.size() > 0) { treeObserver = mElementsList.get(0).view.getViewTreeObserver(); } else { treeObserver = null; } final ViewTreeObserver.OnPreDrawListener preDrawListener = new ViewTreeObserver.OnPreDrawListener() { @Override public boolean onPreDraw() { if (treeObserver.isAlive()) { treeObserver.removeOnPreDrawListener(this); } mFramePoster.postFirstAnimationFrame(); return true; } }; // Try to start animation after any on-going layout round // in the current view tree. OnPreDrawListener seems broken // on pre-Honeycomb devices, start animation immediatelly // in this case. if (Versions.feature11Plus && treeObserver != null && treeObserver.isAlive()) { treeObserver.addOnPreDrawListener(preDrawListener); } else { mFramePoster.postFirstAnimationFrame(); } if (mListeners != null) { for (PropertyAnimationListener listener : mListeners) { listener.onPropertyAnimationStart(); } } } /** * Stop the animation, optionally snapping to the end position. * onPropertyAnimationEnd is only called when snapping to the end position. */ public void stop(boolean snapToEndPosition) { mFramePoster.cancelAnimationFrame(); // Make sure to snap to the end position. for (ElementHolder element : mElementsList) { if (snapToEndPosition) invalidate(element, element.to); ViewCompat.setHasTransientState(element.view, false); if (shouldEnableHardwareLayer(element)) { element.view.setLayerType(View.LAYER_TYPE_NONE, null); } else { element.view.setDrawingCacheEnabled(false); } } mElementsList.clear(); if (mListeners != null) { if (snapToEndPosition) { for (PropertyAnimationListener listener : mListeners) { listener.onPropertyAnimationEnd(); } } mListeners.clear(); mListeners = null; } } public void stop() { stop(true); } private boolean shouldEnableHardwareLayer(ElementHolder element) { if (Versions.preHC) { return false; } if (!mUseHardwareLayer) { return false; } if (!(element.view instanceof ViewGroup)) { return false; } if (element.property == Property.ALPHA || element.property == Property.TRANSLATION_Y || element.property == Property.TRANSLATION_X) { return true; } return false; } private void invalidate(final ElementHolder element, final float delta) { final View view = element.view; // check to see if the view was detached between the check above and this code // getting run on the UI thread. if (view.getHandler() == null) return; if (element.property == Property.ALPHA) element.proxy.setAlpha(delta); else if (element.property == Property.TRANSLATION_Y) element.proxy.setTranslationY(delta); else if (element.property == Property.TRANSLATION_X) element.proxy.setTranslationX(delta); else if (element.property == Property.SCROLL_Y) element.proxy.scrollTo(element.proxy.getScrollX(), (int) delta); else if (element.property == Property.SCROLL_X) element.proxy.scrollTo((int) delta, element.proxy.getScrollY()); else if (element.property == Property.WIDTH) element.proxy.setWidth((int) delta); else if (element.property == Property.HEIGHT) element.proxy.setHeight((int) delta); } private static abstract class FramePoster { public static FramePoster create(Runnable r) { if (Versions.feature16Plus) { return new FramePosterPostJB(r); } return new FramePosterPreJB(r); } public abstract void postFirstAnimationFrame(); public abstract void postNextAnimationFrame(); public abstract void cancelAnimationFrame(); } private static class FramePosterPreJB extends FramePoster { // Default refresh rate in ms. private static final int INTERVAL = 10; private final Handler mHandler; private final Runnable mRunnable; public FramePosterPreJB(Runnable r) { mHandler = new Handler(); mRunnable = r; } @Override public void postFirstAnimationFrame() { mHandler.post(mRunnable); } @Override public void postNextAnimationFrame() { mHandler.postDelayed(mRunnable, INTERVAL); } @Override public void cancelAnimationFrame() { mHandler.removeCallbacks(mRunnable); } } private static class FramePosterPostJB extends FramePoster { private final Choreographer mChoreographer; private final Choreographer.FrameCallback mCallback; public FramePosterPostJB(final Runnable r) { mChoreographer = Choreographer.getInstance(); mCallback = new Choreographer.FrameCallback() { @Override public void doFrame(long frameTimeNanos) { r.run(); } }; } @Override public void postFirstAnimationFrame() { postNextAnimationFrame(); } @Override public void postNextAnimationFrame() { mChoreographer.postFrameCallback(mCallback); } @Override public void cancelAnimationFrame() { mChoreographer.removeFrameCallback(mCallback); } } }