Android P Keyguard Scrim快速滅屏亮屏閃亮

MTK在android P上會出現在設定鎖屏滑動時候，會出現快速滅屏亮屏閃亮現象。

在開發者模式關掉動畫時不會出現此問題(Keyguard Scrim動畫問題)

解決辦法：setDuration(0),使keyguard scrim動畫關閉,邏輯請打上callback檢視。

堆棧列印參考: Android源碼開發基本指令

/frameworks/base/packages/SystemUI/src/com/android/systemui/statusbar/phone/ScrimController.java
protected void updateScrims() {
    setScrimInFrontAlpha(mCurrentInFrontAlpha);
    setScrimBehindAlpha(mCurrentBehindAlpha);

    dispatchScrimsVisible();
}

private void setScrimBehindAlpha(float alpha) {
    setScrimAlpha(mScrimBehind, alpha);
}

private void setScrimInFrontAlpha(float alpha) {
    setScrimAlpha(mScrimInFront, alpha);
}

private void setScrimAlpha(ScrimView scrim, float alpha) {
    if (alpha == 0f) {
        scrim.setClickable(false);
    } else {
        // Eat touch events (unless dozing or pulsing).
        scrim.setClickable(mState != ScrimState.AOD && mState != ScrimState.PULSING);
    }
    updateScrim(scrim, alpha);
}

private void updateScrim(ScrimView scrim, float alpha) {
    ...
    if (wantsAlphaUpdate || wantsTintUpdate) {
        if (mAnimateChange) {
            startScrimAnimation(scrim, currentAlpha);
        } else {
            // update the alpha directly
            updateScrimColor(scrim, alpha, getCurrentScrimTint(scrim));
            onFinished();
        }
    } else {
        onFinished();
    }
}

private void startScrimAnimation(final View scrim, float current) {
    ValueAnimator anim = ValueAnimator.ofFloat(0f, 1f);
    final int initialScrimTint = scrim instanceof ScrimView ? ((ScrimView) scrim).getTint() :
            Color.TRANSPARENT;
    anim.addUpdateListener(animation -> {
        final float startAlpha = (Float) scrim.getTag(TAG_START_ALPHA);
        final float animAmount = (float) animation.getAnimatedValue();
        final int finalScrimTint = getCurrentScrimTint(scrim);
        final float finalScrimAlpha = getCurrentScrimAlpha(scrim);
        float alpha = MathUtils.lerp(startAlpha, finalScrimAlpha, animAmount);
        alpha = MathUtils.constrain(alpha, 0f, 1f);
        int tint = ColorUtils.blendARGB(initialScrimTint, finalScrimTint, animAmount);
        updateScrimColor(scrim, alpha, tint);
        dispatchScrimsVisible();
    });
    anim.setInterpolator(mInterpolator);
    anim.setStartDelay(mAnimationDelay);
    anim.setDuration(mAnimationDuration);   //setDuration(0),使keyguard scrim動畫關閉，就不會出現android p快速滅屏出現閃屏 
    anim.addListener(new AnimatorListenerAdapter() {
        @Override
        public void onAnimationEnd(Animator animation) {
            onFinished();
            scrim.setTag(TAG_KEY_ANIM, null);
            dispatchScrimsVisible();

            if (!mDeferFinishedListener && mOnAnimationFinished != null) {
                mOnAnimationFinished.run();
                mOnAnimationFinished = null;
            }
        }
    });

    // Cache alpha values because we might want to update this animator in the future if
    // the user expands the panel while the animation is still running.
    scrim.setTag(TAG_START_ALPHA, current);
    scrim.setTag(TAG_END_ALPHA, getCurrentScrimAlpha(scrim));

    scrim.setTag(TAG_KEY_ANIM, anim);
    anim.start();
}