super.onCreate(savedInstanceState);

    getWindow().setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,

            WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);

    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,

            WindowManager.LayoutParams.FLAG_FULLSCREEN);

    requestWindowFeature(Window.FEATURE_NO_TITLE);

    WindowManager.LayoutParams attrs;

    attrs = getWindow().getAttributes();

// attrs.extend |= WindowManager.LayoutParams.EXTEND_IGNORE_HOME_KEY;

getWindow().setAttributes(attrs);

    setContentView(R.layout.activity_main);、

如上代码，可在代码中搞定无标题、全屏、保持屏幕开启状态。

一般地，我们在manifest中搞定这些。