android下拉通知栏清除button修改到通知栏底部显示实现

原生的通知button交互上比较难用，直接上修改。

button布局不同机型位置具体情况按自己的设备设置好，下面是当前实现项目的布局，仅供参考.

frameworks\base\packages\SystemUI\res\layout\status_bar_expanded.xml

<ImageView
android:id="@+id/ic_clear_all_notification"
android:id=layout_width="wrap_content"
android:id=layout_height="wrap_content"
android:id=layout_graviity="center|bottom"
android:layout_marginBottom="25.0dip"
android:scaleType="fitXY"
android:src="@drawable/ic_clear_all_notification"
/>

Java代码修改：

frameworks\base\packages\SystemUI\src\com\android\systemui\statusbar\phone\NotificationPanelView.java

protected void onFinishInflate() {
    
    
...
        //add for notification clear button
        mClearView =(ImageView)findViewById(R.id.ic_clear_all_notification);
        mClearView.setOnClickListener(new View.OnClickListener(){
    
    
           @Override
           public void onClick(View v) {
    
    
              mStatusBar.clearAllNotifications();
           }
        });
        //add for notification clear button

}

private void updateNotificationTranslucency() {
    
    
    float alpha = 1f;
    if (mClosingWithAlphaFadeOut && !mExpandingFromHeadsUp && !mHeadsUpManager.hasPinnedHeadsUp()) {
    
    
        alpha = getFadeoutAlpha();
    }
    mNotificationStackScroller.setAlpha(alpha);
   
    //add for notification clear button
    KeyguardManager keyguardManager =
            (KeyguardManager) getContext().getSystemService(Context.KEYGUARD_SERVICE);
    if (keyguardManager.isKeyguardLocked() || mHeadsUpManager.hasPinnedHeadsUp()) {
    
    
        mClearView.setVisibility(View.INVISIBLE);

    } else {
    
    
        mClearView.setVisibility(ifHasActiveClearableNotifications() ? View.VISIBLE : View.INVISIBLE);
    }
    //add for notification clear button
}

控制button是否应该显示的关键方法
    /**
    * Return whether there are any clearable notifications
    */
    private boolean ifHasActiveClearableNotifications() {
    
    
        int childCount = mNotificationStackScroller.getChildCount();
        for (int i = 0; i < childCount; i++) {
    
    
            View child = mNotificationStackScroller.getChildAt(i);
            if (!(child instanceof ExpandableNotificationRow)) {
    
    
                continue;
            }
            if (((ExpandableNotificationRow) child).canViewBeDismissed()) {
    
    
                return true;
            }
        }
        return false;
    }

移除原生默认的DismissView的显示
frameworks\base\packages\SystemUI\src\com\android\systemui\statusbar\DismissView.java
 protected void onFinishInflate() {
    
    
        super.onFinishInflate();
        mDismissButton = (DismissViewButton) findContentView();
        +mDismissButton.setVisibility(View.GONE);
    }

小小的记录一笔，欢迎指正交流.