//设置为无标题
requestWindowFeature(Window.FEATURE_NO_TITLE);
//设置为全屏模式getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN

WindowManager windowManager = getWindowManager();
Display display = windowManager.getDefaultDisplay();
screenWidth = display.getWidth();
screenHeight = display.getHeight();

DisplayMetrics dm = new DisplayMetrics();
this.getWindowManager().getDefaultDisplay().getMetrics(dm);//this指当前activity
screenWidth =dm.widthPixels;
screenHeight =dm.heightPixels;

@Override
 protected void onDraw(Canvas canvas) {
  super.onDraw(canvas);
 screenWidth =canvas.getWidth();
 screenHeight =canvas.getHeight();
}

protected void onSizeChanged(int w, int h, int oldw, int oldh) {
viewHeight=h;
viewWidth=w;
super.onSizeChanged(w, h, oldw, oldh);
}