尝试使用 SlidingPaneLayout 时，我在 Fragment 的 onCreateView() 内遇到空指针异常。
mSlidingLayout.setPanelSlideListener(new SliderListener());
如果我删除了此 SlidingPaneLayout 的使用，并仅在片段中显示某个内容的 Textview，则它可以正常工作。
下面是 onCreateView 代码以及 LogCat 错误输出。
public class FragmentwithSlidingPane extends Fragment {
ListView lv_addblockparameters;
private SlidingPaneLayout mSlidingLayout;
private ListView mList;
private ActionBarHelper mActionBar;
//Constructor
public FragmentwithSlidingPane() {}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_testlayout, container, false);
/*
* Following code from:
* http://androidtrainningcenter.blogspot.com/2013/06/slidingpanelayout-android-making.html
*/
mSlidingLayout = (SlidingPaneLayout) rootView.findViewById(R.id.sliding_pane_layout);
mList = (ListView) rootView.findViewById(R.id.left_pane);
/********************************
* LINE BELOW IS WHERE I GET NULLPOINTEREXCEPTION
* This line is FragmentwithSlidingPane.java:71 stated in error trace below
*********************************/
mSlidingLayout.setPanelSlideListener(new SliderListener());
mSlidingLayout.openPane();
//Populating the Listview
String List[] = new String[5];
List[0] = "Apps >>";
List[1] ="URLs >>";
List[2] ="Notifications >>";
List[3] ="Texts >>";
List[4] ="Calls >>";
mList.setAdapter(new ArrayAdapter<String>(getActivity(),
android.R.layout.simple_list_item_1, List));
mList.setOnItemClickListener(new ListItemClickListener());
return rootView;
}
}
/**
* This panel slide listener updates the action bar accordingly for each
* panel state.
*/
private class SliderListener extends
SlidingPaneLayout.SimplePanelSlideListener {
@Override
public void onPanelOpened(View panel) {
mActionBar.onPanelOpened();
}
@Override
public void onPanelClosed(View panel) {
mActionBar.onPanelClosed();
}
}
下面是我的 LogCat 错误输出。
06-28 23:45:31.322: E/AndroidRuntime(4294): FATAL EXCEPTION: main
06-28 23:45:31.322: E/AndroidRuntime(4294): Process: com.mavdev.focusoutfacebook, PID: 4294
06-28 23:45:31.322: E/AndroidRuntime(4294): java.lang.NullPointerException
06-28 23:45:31.322: E/AndroidRuntime(4294): at com.mavdev.focusoutfacebook.fragments.FragmentwithSlidingPane.onCreateView(FragmentwithSlidingPane.java:71)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.support.v4.app.Fragment.performCreateView(Fragment.java:1500)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:938)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1115)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1478)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:446)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.os.Handler.handleCallback(Handler.java:733)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.os.Handler.dispatchMessage(Handler.java:95)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.os.Looper.loop(Looper.java:136)
06-28 23:45:31.322: E/AndroidRuntime(4294): at android.app.ActivityThread.main(ActivityThread.java:5017)
06-28 23:45:31.322: E/AndroidRuntime(4294): at java.lang.reflect.Method.invokeNative(Native Method)
06-28 23:45:31.322: E/AndroidRuntime(4294): at java.lang.reflect.Method.invoke(Method.java:515)
06-28 23:45:31.322: E/AndroidRuntime(4294): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:779)
06-28 23:45:31.322: E/AndroidRuntime(4294): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595)
06-28 23:45:31.322: E/AndroidRuntime(4294): at dalvik.system.NativeStart.main(Native Method)