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@amlcurran
Last active July 18, 2018 11:24
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Class which allows animation between two colors. Compatible with NineOldAndroids or the standard Android Animator APIs.
/**
* Copyright 2013 Alex Curran
*
* 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 com.espian.snippets;
import android.animation.ObjectAnimator;
import android.animation.TypeEvaluator;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.view.View;
/**
* Class which allows animation between two colors. Compatible with NineOldAndroids or the standard
* Android animation APIs (make sure you change the imports when using NOA).
* <p/>
* When using with background colors for views, ensure you use the {@link ViewBackgroundWrapper} class.
* {@link View} does not have a <code>getBackgroundColor()</code> method required by the {@link ObjectAnimator}
* framework; the wrapper class solves this issue.
*/
public class ColorAnimator {
public static ObjectAnimator ofColor(Object target, String propertyName, int from, int to) {
return ObjectAnimator.ofObject(target, propertyName, new ColorEvaluator(), from, to);
}
public static ObjectAnimator ofColor(Object target, String propertyName, int to) {
return ObjectAnimator.ofObject(target, propertyName, new ColorEvaluator(), to);
}
public static ObjectAnimator ofBackgroundColor(View target, int from, int to) {
return ObjectAnimator.ofObject(new ViewBackgroundWrapper(target), "backgroundColor", new ColorEvaluator(), from, to);
}
public static ObjectAnimator ofBackgroundColor(View target, int to) {
return ObjectAnimator.ofObject(new ViewBackgroundWrapper(target), "backgroundColor", new ColorEvaluator(), to);
}
private static class ColorEvaluator implements TypeEvaluator<Integer> {
@Override
public Integer evaluate(float fraction, Integer startValue, Integer endValue) {
int startA, startR, startG, startB;
int aDelta = (int) ((Color.alpha(endValue) - (startA = Color.alpha(startValue))) * fraction);
int rDelta = (int) ((Color.red(endValue) - (startR = Color.red(startValue))) * fraction);
int gDelta = (int) ((Color.green(endValue) - (startG = Color.green(startValue))) * fraction);
int bDelta = (int) ((Color.blue(endValue) - (startB = Color.blue(startValue))) * fraction);
return Color.argb(startA + aDelta, startR + rDelta, startG + gDelta, startB + bDelta);
}
}
/**
* Helper class which allows retrieval of a {@link View}'s background as a color.
*/
public static class ViewBackgroundWrapper {
private View mView;
public ViewBackgroundWrapper(View v) {
mView = v;
}
public int getBackgroundColor() {
try {
return ((ColorDrawable) mView.getBackground()).getColor();
} catch (ClassCastException cce) {
// The background isn't a ColorDrawable (could be BitmapDrawable etc.) - throw a more descriptive error
throw new IllegalStateException(
String.format("Attempt to read View background color when background isn't a ColorDrawable (is %s instead)",
mView.getBackground().getClass().getSimpleName()));
}
}
public void setBackgroundColor(int color) {
mView.setBackgroundColor(color);
}
}
}
@oli-g-sk
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oli-g-sk commented Aug 8, 2017

One example - crossfading a view's background color:
ObjectAnimator animator = ColorAnimator.ofBackgroundColor(myView, ContextCompat.getColor(this, R.color.some_color));
animator.start();

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