Java tutorial
/* 50AH-code ========= 50 Android Hacks (http://manning.com/sessa/) book source code Copyright (c) 2012 Manning Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ package com.actionbarsherlock.internal.nineoldandroids.view.animation; import java.lang.ref.WeakReference; import java.util.WeakHashMap; import android.graphics.Matrix; import android.graphics.RectF; import android.os.Build; import android.util.FloatMath; import android.view.View; import android.view.animation.Animation; import android.view.animation.Transformation; public final class AnimatorProxy extends Animation { public static final boolean NEEDS_PROXY = Build.VERSION.SDK_INT < Build.VERSION_CODES.HONEYCOMB; private static final WeakHashMap<View, AnimatorProxy> PROXIES = new WeakHashMap<View, AnimatorProxy>(); public static AnimatorProxy wrap(View view) { AnimatorProxy proxy = PROXIES.get(view); if (proxy == null) { proxy = new AnimatorProxy(view); PROXIES.put(view, proxy); } return proxy; } private final WeakReference<View> mView; private float mAlpha = 1; private float mScaleX = 1; private float mScaleY = 1; private float mTranslationX; private float mTranslationY; private final RectF mBefore = new RectF(); private final RectF mAfter = new RectF(); private final Matrix mTempMatrix = new Matrix(); private AnimatorProxy(View view) { setDuration(0); //perform transformation immediately setFillAfter(true); //persist transformation beyond duration view.setAnimation(this); mView = new WeakReference<View>(view); } public float getAlpha() { return mAlpha; } public void setAlpha(float alpha) { if (mAlpha != alpha) { mAlpha = alpha; View view = mView.get(); if (view != null) { view.invalidate(); } } } public float getScaleX() { return mScaleX; } public void setScaleX(float scaleX) { if (mScaleX != scaleX) { prepareForUpdate(); mScaleX = scaleX; invalidateAfterUpdate(); } } public float getScaleY() { return mScaleY; } public void setScaleY(float scaleY) { if (mScaleY != scaleY) { prepareForUpdate(); mScaleY = scaleY; invalidateAfterUpdate(); } } public int getScrollX() { View view = mView.get(); if (view == null) { return 0; } return view.getScrollX(); } public void setScrollX(int value) { View view = mView.get(); if (view != null) { view.scrollTo(value, view.getScrollY()); } } public int getScrollY() { View view = mView.get(); if (view == null) { return 0; } return view.getScrollY(); } public void setScrollY(int value) { View view = mView.get(); if (view != null) { view.scrollTo(view.getScrollY(), value); } } public float getTranslationX() { return mTranslationX; } public void setTranslationX(float translationX) { if (mTranslationX != translationX) { prepareForUpdate(); mTranslationX = translationX; invalidateAfterUpdate(); } } public float getTranslationY() { return mTranslationY; } public void setTranslationY(float translationY) { if (mTranslationY != translationY) { prepareForUpdate(); mTranslationY = translationY; invalidateAfterUpdate(); } } private void prepareForUpdate() { View view = mView.get(); if (view != null) { computeRect(mBefore, view); } } private void invalidateAfterUpdate() { View view = mView.get(); if (view == null) { return; } View parent = (View) view.getParent(); if (parent == null) { return; } view.setAnimation(this); final RectF after = mAfter; computeRect(after, view); after.union(mBefore); parent.invalidate((int) FloatMath.floor(after.left), (int) FloatMath.floor(after.top), (int) FloatMath.ceil(after.right), (int) FloatMath.ceil(after.bottom)); } private void computeRect(final RectF r, View view) { // compute current rectangle according to matrix transformation final float w = view.getWidth(); final float h = view.getHeight(); // use a rectangle at 0,0 to make sure we don't run into issues with scaling r.set(0, 0, w, h); final Matrix m = mTempMatrix; m.reset(); transformMatrix(m, view); mTempMatrix.mapRect(r); r.offset(view.getLeft(), view.getTop()); // Straighten coords if rotations flipped them if (r.right < r.left) { final float f = r.right; r.right = r.left; r.left = f; } if (r.bottom < r.top) { final float f = r.top; r.top = r.bottom; r.bottom = f; } } private void transformMatrix(Matrix m, View view) { final float w = view.getWidth(); final float h = view.getHeight(); final float sX = mScaleX; final float sY = mScaleY; if ((sX != 1.0f) || (sY != 1.0f)) { final float deltaSX = ((sX * w) - w) / 2f; final float deltaSY = ((sY * h) - h) / 2f; m.postScale(sX, sY); m.postTranslate(-deltaSX, -deltaSY); } m.postTranslate(mTranslationX, mTranslationY); } @Override protected void applyTransformation(float interpolatedTime, Transformation t) { View view = mView.get(); if (view != null) { t.setAlpha(mAlpha); transformMatrix(t.getMatrix(), view); } } @Override public void reset() { /* Do nothing. */ } }