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Commit bf206123 authored by Sunny Goyal's avatar Sunny Goyal
Browse files

Blocking alpha animation if the initial and final state for the animation 

are both 0

Bug: 30739854
Change-Id: I4f7c579dc3f64a4fed60d7b2f8ecd5f359e165ec
parent c9a0a7c6

src/com/android/launcher3/util/MultiStateAlphaController.java

+46 −3
Original line number Diff line number Diff line
@@ -17,6 +17,7 @@ 
package com.android.launcher3.util;



import android.animation.Animator;

import android.animation.AnimatorListenerAdapter;

import android.animation.ValueAnimator;

import android.animation.ValueAnimator.AnimatorUpdateListener;

import android.content.Context;
@@ -33,6 +34,7 @@ public class MultiStateAlphaController { 
    private final View mTargetView;

    private final float[] mAlphas;

    private final AccessibilityManager mAm;

    private int mZeroAlphaListenerCount = 0;



    public MultiStateAlphaController(View view, int stateCount) {

        mTargetView = view;
@@ -44,12 +46,20 @@ public class MultiStateAlphaController { 


    public void setAlphaAtIndex(float alpha, int index) {

        mAlphas[index] = alpha;

        updateAlpha();

    }



    private void updateAlpha() {

        // Only update the alpha if no zero-alpha animation is running.

        if (mZeroAlphaListenerCount > 0) {

            return;

        }

        float finalAlpha = 1;

        for (float a : mAlphas) {

            finalAlpha = finalAlpha * a;

        }

        mTargetView.setAlpha(finalAlpha);

        mTargetView.setVisibility(alpha > 0 ? View.VISIBLE

        mTargetView.setVisibility(finalAlpha > 0 ? View.VISIBLE

                : (mAm.isEnabled() ? View.GONE : View.INVISIBLE));

    }
@@ -58,9 +68,11 @@ public class MultiStateAlphaController { 
     * to {@param finalAlpha}. Alphas at other index are not affected.

     */

    public Animator animateAlphaAtIndex(float finalAlpha, final int index) {

        final ValueAnimator anim;



        if (Float.compare(finalAlpha, mAlphas[index]) == 0) {

            // Return a dummy animator to avoid null checks.

            return ValueAnimator.ofFloat(0, 0);

            anim = ValueAnimator.ofFloat(0, 0);

        } else {

            ValueAnimator animator = ValueAnimator.ofFloat(mAlphas[index], finalAlpha);

            animator.addUpdateListener(new AnimatorUpdateListener() {
@@ -70,7 +82,38 @@ public class MultiStateAlphaController { 
                    setAlphaAtIndex(value, index);

                }

            });

            return animator;

            anim = animator;

        }



        if (Float.compare(finalAlpha, 0f) == 0) {

            // In case when any channel is animating to 0, and the current alpha is also 0, do not

            // update alpha of the target view while the animation is running.

            // We special case '0' because if any channel is set to 0, values of other

            // channels do not matter.

            anim.addListener(new ZeroAlphaAnimatorListener());

        }

        return anim;

    }



    private class ZeroAlphaAnimatorListener extends AnimatorListenerAdapter {



        private boolean mStartedAtZero = false;



        @Override

        public void onAnimationStart(Animator animation) {

            mStartedAtZero = Float.compare(mTargetView.getAlpha(), 0f) == 0;

            if (mStartedAtZero) {

                mZeroAlphaListenerCount++;

                mTargetView.setAlpha(0);

            }

        }



        @Override

        public void onAnimationEnd(Animator animation) {

            if (mStartedAtZero) {

                mZeroAlphaListenerCount--;

                updateAlpha();

            }

        }

    }

}