程序在Android中制作自定义标题栏时被粉碎

Question

我喜欢制作自定义标题栏。最重要的是，我想添加一个带加号的按钮。 制作自定义标题var I follow this link的第一步。但是我在MainActivity.java中遇到了问题。当我到达setContentView(R.layout.activity_main);行时，我的程序被粉碎了。我的代码如下所示

public class MainActivity extends ListActivity {

String[] presidents = { "Dwight D. Eisenhower", "John F. Kennedy",
        "Lyndon B. Johnson", "Richard Nixon", "Gerald Ford",
        "Jimmy Carter", "Ronald Reagan", "George H. W. Bush",
        "Bill Clinton", "George W. Bush", "Barack Obama"};

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
    setContentView(R.layout.activity_main);
    getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.mytitle);

    /*
    // ---List View--- setListAdapter(new ArrayAdapter<String>(this,
    android.R.layout.simple_list_item_1, presidents));
    */

    // ---Part 2---
    ListView lstView = getListView();
    // lstView.setChoiceMode(ListView.CHOICE_MODE_NONE);
    // lstView.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
     lstView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE);

    setListAdapter(new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_checked, presidents));


}