PhotographicPrintAnimator

PhotographicPrintAnimator realize a beautiful photographic print animation as described in the Material design spec (http://www.google.com/design/spec/patterns/loading-images.html#loading-images-loading-images)

Text file (2 KB): gistfile1.txt

import android.animation.ValueAnimator;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.view.animation.AccelerateDecelerateInterpolator;
import android.view.animation.Interpolator;
import android.widget.ImageView;

import java.lang.ref.SoftReference;

public class PhotographicPrintAnimator {

    final SoftReference<ImageView> mView;
    final ColorMatrix mColorMatrix;
    final float[] mBrightness = new float[]
            {
                    1, 0, 0, 0, 0,
                    0, 1, 0, 0, 0,
                    0, 0, 1, 0, 0,
                    0, 0, 0, 1, 0
            };

    final ColorMatrix mBrightnessColorMatrix;
    final Interpolator mInterpolator;

    public PhotographicPrintAnimator(ImageView v) {
        mView = new SoftReference<ImageView>(v);
        mColorMatrix = new ColorMatrix();
        mBrightnessColorMatrix = new ColorMatrix();
        mInterpolator = new AccelerateDecelerateInterpolator();
    }

    public void start(int duration) {


        final ValueAnimator v = ValueAnimator.ofFloat(0f, 1f);
        final ValueAnimator v2 = ValueAnimator.ofFloat(0f, 1f);

        v.setInterpolator(mInterpolator);
        v.setDuration(duration);
        v.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {
                mColorMatrix.setSaturation(animation.getAnimatedFraction());

                if (mView.get() != null) {
                    mView.get().setColorFilter(new ColorMatrixColorFilter(mColorMatrix));
                } else {
                    v.cancel();
                    v2.cancel();
                }
            }
        });

        v2.setInterpolator(mInterpolator);
        v2.setDuration((int) (duration * 0.75));
        v2.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
            @Override
            public void onAnimationUpdate(ValueAnimator animation) {

                float brightness = (1f - animation.getAnimatedFraction()) * 255;
                mBrightness[4] = brightness;
                mBrightness[9] = brightness;
                mBrightness[14] = brightness;
                mBrightnessColorMatrix.set(mBrightness);
                mColorMatrix.postConcat(mBrightnessColorMatrix);

                if (mView.get() != null) {
                    mView.get().setColorFilter(new ColorMatrixColorFilter(mColorMatrix));
                } else {
                    v.cancel();
                    v2.cancel();
                }
            }
        });

        if (mView.get() != null) {
            mView.get().setAlpha(0f);
            mView.get().animate().alpha(1.0f).setDuration(duration / 2);
            v.start();
            v2.start();
        }
    }
}