上滑通知栏Notification中smallIcon的显示影响因素

NotificationIconContainer.java

calculateIconTranslations(){

......

if (firstOverflowIndex != -1) {
    int numDots = 1;
    translationX = visualOverflowStart;
    for (int i = firstOverflowIndex; i < childCount; i++) {
        View view = getChildAt(i);
        IconState iconState = mIconStates.get(view);
        int dotWidth = mStaticDotRadius * 2 + mDotPadding;
        iconState.xTranslation = translationX;
        if (numDots <= 3) {
            if (numDots == 1 && iconState.iconAppearAmount < 0.8f) {
                iconState.visibleState = StatusBarIconView.STATE_ICON;//Icon显示为通知自己的Icon
                numDots--;
            } else {
                iconState.visibleState = StatusBarIconView.STATE_DOT;//Icon显示为一个点
            }
            translationX += (numDots == 3 ? 3 * dotWidth : dotWidth)
                    * iconState.iconAppearAmount;
        } else {
            iconState.visibleState = StatusBarIconView.STATE_HIDDEN;
        }
        numDots++;
    }
}

}

控制Icon显示为点的控制是iconState.visibleState = StatusBarIconView.STATE_DOT;我们发现屏蔽该句代码,可以将显示为点的通知显示为图标,那我们看判断条件(numDots == 1 && iconState.iconAppearAmount < 0.8f)是如何控制的,但是我们发现该处并不能发现导致显示差异的根本原因,于是继续向上找判断,如果条件(firstOverflowIndex != -1)不成立,也不会执行iconState.visibleState = StatusBarIconView.STATE_DOT该段语句,不过我们要尝试屏蔽掉条件中的所有代码,看一下是否影响其他图标的显示,发现不影响,那么追看(firstOverflowIndex != -1)不成立的条件,在该方法中继续向上看,有赋值语句如下:

firstOverflowIndex = noOverflowAfter && !forceOverflow ? i - 1 : i;

继续向上看有

boolean forceOverflow = mSpeedBumpIndex != -1 && i >= mSpeedBumpIndex
        && iconState.iconAppearAmount > 0.0f || i >= maxVisibleIcons;

发现forceOverflow和mSpeedBumpIndex有关,而StatusBar.java中有方法updateSpeedBumpIndex方法,如下

private void updateSpeedBumpIndex() {
    int speedBumpIndex = 0;
    int currentIndex = 0;
    final int N = mStackScroller.getChildCount();
    for (int i = 0; i < N; i++) {
        View view = mStackScroller.getChildAt(i);
        if (view.getVisibility() == View.GONE || !(view instanceof ExpandableNotificationRow)) {
            continue;
        }
        ExpandableNotificationRow row = (ExpandableNotificationRow) view;
        currentIndex++;
            if (!mNotificationData.isAmbient(row.getStatusBarNotification().getKey())) {
            speedBumpIndex = currentIndex;
        }
    }
    boolean noAmbient = speedBumpIndex == N;
    mStackScroller.updateSpeedBumpIndex(speedBumpIndex, noAmbient);
}

影响最终结果的是speedBumpIndex,看判断条件(!mNotificationData.isAmbient(row.getStatusBarNotification().getKey())),进入NotificationData的isAmbient方法,如下

public boolean isAmbient(String key) {
    if (mRankingMap != null) {
        getRanking(key, mTmpRanking);
        return mTmpRanking.isAmbient();
    }
    return false;
}

再进入NotificationListenerService的isAmbient方法,如下

/**
 * Returns whether the notification is an ambient notification, that is
 * a notification that doesn't require the user's immediate attention.
 *返回通知是否为环境通知，即不需要用户立即关注的通知。
 */
public boolean isAmbient() {
    return mIsAmbient;
}

查看mIsAmbient的赋值位置,如下

mIsAmbient = importance < NotificationManager.IMPORTANCE_LOW;

也就是说通知的重要性小于IMPORTANCE_LOW的通知都是环境通知,会显示在通知栏的底部,上滑的过程中会显示为点,并且不会显示在状态栏中

上滑通知栏Notification中smallIcon的显示影响因素

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