java Android调用onAttachedToWindow（）时，我们可以隐藏状态栏吗？

Question

当调用OnAttachedToWindows且窗口类型为keyguard时，有一种方法可以隐藏或禁用状态栏？？ 我在我的活动课上试过：

这是onCreate

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setWindowAnimations(0);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.activity_lock); 
}

public void onAttachedToWindow() {
    super.onAttachedToWindow();
    getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
}

这在我的舱单上

安卓:theme="@安卓:style/Theme.NoTitleBar.Fullscreen";

但有时状态栏会消失，有时会出现

如果我试试这个：

public void onAttachedToWindow() {
    super.onAttachedToWindow();
    getWindow().setType(WindowManager.LayoutParams.TYPE_KEYGUARD);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
}

这给了我一个错误：

12-22 11:03:51.209: E/AndroidRuntime(9088): 安卓.util.AndroidRuntimeException: requestFeature() must be called before adding content