Android 尝试在片段（onCreateView）中使用SlidingPanel布局时的nullpointerexpection

在尝试使用SlidingPaneLayout时，我在片段的onCreateView（）中遇到一个nullpointer异常

mSlidingLayout.setPanelSlideListener（新的SliderListener（））

如果我取消使用这个SlidengPanelAyout，只显示片段中某个内容的文本视图，它就可以正常工作

下面是onCreateView代码和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;
}

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)

---

我认为您选择了错误的xml文件，我的意思是：

fragment\u testlayout

NullPointerException通常意味着对象实际上并不存在。仔细检查您的fragment_testlayout.xml文件是否真的有id=“@+id/Slideng_pane_layout”的SlidengPanelayout？我想您选择了错误的xml文件我的意思是：fragment_testlayout我通常会这样做：D

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)