The purpose is to pop-up to dialog, activity can still receive events
//清除灰色背景
getWindow().clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE,WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE);
//点击外部区域不可取消,这句可以不用,没啥关系
setCanceledOnTouchOutside(false);