本文基于Android5.1
frameworks/base/packages/SystemUI_usb/src/com/android/systemui/statusbar/phone/PhoneStatusBarView.java
selectPanelForTouch()方法入口
//修改去掉下拉通知栏 return null
@Override
public PanelView selectPanelForTouch(MotionEvent touch) {
// No double swiping. If either panel is open, nothing else can be pulled down.
/* return mNotificationPanel.getExpandedHeight() > 0
? null
: mNotificationPanel;*/
return null;
}