android.util.AndroidRuntimeException: requestFeature() must be called before adding content

Activity全屏，网上的代码如下：

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);//去掉标题栏
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);//去掉信息栏
setContentView(R.layout.activity_main);

}

报错：android.util.AndroidRuntimeException: requestFeature() must be called before adding content

解决如下：

protected void onCreate(Bundle savedInstanceState) {

this.requestWindowFeature(Window.FEATURE_NO_TITLE);//去掉标题栏

this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);//去掉信息栏

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

}