DrawerLayout无法投射

Question

当我尝试在手机上安装我的应用程序进行测试时，我得到的DrawerLayout无法投出错误。这只是一个基本的滑出式抽屉。我是新手，所以你能做的任何事情都会很棒！

这是我的主要活动：

public class MainActivity extends Activity {

private FragmentNavigationDrawer dlDrawer;

public final static String EXTRA_MESSAGE = "Nothing";

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

 // Find our drawer view
        dlDrawer = (FragmentNavigationDrawer) findViewById(R.id.drawer_layout);
        // Setup drawer view
        dlDrawer.setupDrawerConfiguration((ListView) findViewById(R.id.lvDrawer), 
                      R.layout.drawer_list_item, R.id.flContent);
        // Add nav items
    //  dlDrawer.addNavItem("First", "Text Note", TextNoteFragment.class);
        //dlDrawer.addNavItem("Second", "Second Fragment", SecondFragment.class);
        //dlDrawer.addNavItem("Third", "Third Fragment", ThirdFragment.class);
        // Select default
        if (savedInstanceState == null) {
            dlDrawer.selectDrawerItem(0);   
        }



}

public boolean onPrepareOptionsMenu(Menu menu) {
    // If the nav drawer is open, hide action items related to the content
    if (dlDrawer.isDrawerOpen()) {
        menu.findItem(R.id.action_search).setVisible(false);

    }
    return super.onPrepareOptionsMenu(menu);
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    MenuInflater inflater = getMenuInflater();
    inflater.inflate(R.menu.main, menu);
    return super.onCreateOptionsMenu(menu);
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle presses on the action bar items
    if (dlDrawer.getDrawerToggle().onOptionsItemSelected(item)) {
        return true;
    }
    switch (item.getItemId()) {
        case R.id.action_search:
            openSearch();
            return true;
        case R.id.action_settings:
            openSettings();
            return true;
        case R.id.help_setting:
            openHelp();
            return true;

        default:
            return super.onOptionsItemSelected(item);
    }
}

@Override
protected void onPostCreate(Bundle savedInstanceState) {
    super.onPostCreate(savedInstanceState);
    // Sync the toggle state after onRestoreInstanceState has occurred.
    dlDrawer.getDrawerToggle().syncState();
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
    super.onConfigurationChanged(newConfig);
    // Pass any configuration change to the drawer toggles
    dlDrawer.getDrawerToggle().onConfigurationChanged(newConfig);
}

public void openHelp() {
    Intent intent = new Intent(this, HelpActivity.class);
    String message = "Will you just shut up already? It's not that hard to figure out.";
    intent.putExtra(EXTRA_MESSAGE,message);
    startActivity(intent);

}


public void openSearch() {
    //Do something here.
}

public void openSettings() {
    Intent intent = new Intent(this,SettingsClass.class);
    startActivity(intent);
}



}

这是我的主要活动XML：

<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- The main content view -->
<!-- The navigation drawer -->


  <FrameLayout
    android:id="@+id/flContent"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

<ListView
    android:id="@+id/lvDrawer" 
    android:layout_width="240dp"
    android:layout_height="match_parent"
    android:layout_gravity="start"
    android:choiceMode="singleChoice"
    android:divider="@android:color/darker_gray"
    android:dividerHeight="0dp"
    android:background="@android:color/background_light"
 />

</android.support.v4.widget.DrawerLayout>