Android-L ActionBar ProgressBar没有显示出来

Question

我正试图通过在我的Activity中以这种方式调用它来使用ActionBar中包含的ProgressBar。

@Override
public void onCreate(Bundle aSavedState) {

    requestWindowFeature(Window.FEATURE_PROGRESS);
    requestWindowFeature(Window.FEATURE_INDETERMINATE_PROGRESS);
    requestWindowFeature(Window.FEATURE_ACTION_BAR);
    requestWindowFeature(Window.PROGRESS_VISIBILITY_ON);
    requestWindowFeature(Window.PROGRESS_START);

    setProgress(10);
    setProgressBarIndeterminateVisibility(true);
    setProgressBarIndeterminate(true);

    super.onCreate(aSavedState);

您认为所有这些功能请求都会显示出来。

你是怎么做到的？