Android/Java.lang.NullPointerException

我是Android编程新手。当Android抛出我时，我正试图通过主活动将一个字符串从左片段发送到右片段

原因：java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法“java.lang.String android.os.Bundle.getStringjava.lang.String”

对于左边的片段，我写道：

MyAdapter listAdapter=new MyAdapter(getData(),this.getActivity() );
        lv_list.setAdapter(listAdapter);
        setListViewHeightBasedOnChildren(lv_list); 
        lv_list.setOnItemClickListener(new OnItemClickListener(){
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                itemCallback.onItemSelected(parent, view, position);
            }
        });

多谢各位。所有建议将不胜感激

我还要添加logcat输出：

10-11 14:24:16.667:E/AndroidRuntime1268:Process:com.example.projet3，PID:1268 10-11 14:24:16.667:E/AndroidRuntime1268:java.lang.RuntimeException:无法启动活动组件信息{com.example.projet3/com.example.projet3.MainActivity}:android.view.InflateException:二进制XML文件第14行：膨胀类片段时出错 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.ActivityThread.PerformLaunchActivityYaActivityThread.java:2325 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.ActivityThread.handleLaunchActivityActivityThread.java:2390 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.ActivityThread.access$800ActivityThread.java:151 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.ActivityThread$H.handleMessageActivityThread.java:1303 10-11 14:24:16.667:E/AndroidRuntime1268:at android.os.Handler.dispatchMessageHandler.java:102 10-11 14:24:16.667:E/AndroidRuntime1268:at android.os.Looper.Looper.java:135 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.ActivityThread.mainActivityThread.java:5257 10-11 14:24:16.667:E/AndroidRuntime1268:at java.lang.reflect.Method.Invokenactive方法 10-11 14:24:16.667:E/AndroidRuntime1268:at java.lang.reflect.Method.invokeMethod.java:372 10-11 14:24:16.667:E/AndroidRuntime1268:com.android.internal.os.ZygoteInit$methodAndArgscaler.runZygoteInit.java:903 10-11 14:24:16.667:E/AndroidRuntime1268:com.android.internal.os.ZygoteInit.mainZygoteInit.java:698 10-11 14:24:16.667:E/AndroidRuntime1268:原因：android.view.InflateException:二进制XML文件第14行：膨胀类片段时出错 10-11 14:24:16.667:E/AndroidRuntime1268:at android.view.LayoutInflater.createViewFromTagLayoutInflater.java:763 10-11 14:24:16.667:E/AndroidRuntime1268:at-android.view.LayoutInflater.rInflateLayoutInflater.java:806 10-11 14:24:16.667:E/AndroidRuntime1268:at android.view.LayoutInflater.inflateLayoutInflater.java:504 10-11 14:24:16.667:E/AndroidRuntime1268:at android.view.LayoutInflater.inflateLayoutInflater.java:414 10-11 14:24:16.667:E/AndroidRuntime1268:at android.view.LayoutInflater.inflateLayoutInflater.java:365 10-11 14:24:16.667:E/AndroidRuntime1268:com.android.internal.policy.impl.PhoneWindow.setContentViewPhoneWindow.java:378 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.Activity.setContentViewActivity.java:2145 10-11 14:24:16.667:E/AndroidRuntime1268:at com.example.projet3.MainActivity.onCreateMainActivity.java:26 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.Activity.performCreateActivity.java:5990 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.Instrumentation.callActivityOnCreateInstrumentation.java:1106 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.ActivityThread.PerformLaunchActivityYaActivityThread.java:2278 10-11 14:24:16.667:E/AndroidRuntime1268:。。。10多 10-11 14:24:16.667:E/AndroidRuntime1268:原因：java.lang.NullPointerException:尝试在空对象引用上调用虚拟方法“java.lang.String android.os.Bundle.getStringjava.lang.String” 10-11 14:24:16.667:E/AndroidRuntime1268:at com.example.projet3.Fg_right.onCreateViewFg_right.java:28 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.Fragment.performCreateViewFragment.java:2053 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.FragmentManagerImpl.moveToStateFragmentManager.java:870 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.FragmentManagerImpl.moveToStateFragmentManager.java:1045 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.FragmentManagerImpl.addFragmentFragmentManager.java:1147 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.FragmentManagerImpl.onCreateViewFragmentManager.java:2116 10-11 14:24:16.667:E/AndroidRuntime1268:at android.app.Activity.onCreateViewActivity.java:5328 10-11 14:24:16.667:E/AndroidRuntime1268:at android.view.LayoutInflater.createViewFromTagLayoutInflater.java:733

---

10-11 14:24:16.667:E/AndroidRuntime1268:。。。20更多logcat怎么说？哪一行是NullPointerException？您正在为fg_right片段类扩展布局fg_left。这是故意的吗？可能您正在设置tv_right的文本属性，而tv_right为空。我已打开日志。我已将布局fg_left更改为fg_right。但这没用。

public void onItemSelected(AdapterView<?> parent, View view, int position) {
        MyAdapter listAdapter = (MyAdapter) parent.getAdapter();
        MainItem item = (MainItem) listAdapter.getItem(position);
        String title=item.getName();
        /*intent = new Intent(this, Fg_right.class);
        intent.putExtra("title", title);*/
        fg_right=new Fg_right();
        fg_right=Fg_right.newInstance(title);
        this.fragmentTransaction = fragmentManager.beginTransaction();
        this.fragmentTransaction.replace(R.id.fg_right, fg_right);
        this.fragmentTransaction.addToBackStack(null);
        this.fragmentTransaction.commit();

        }

public class Fg_right extends Fragment {  
     String title="";  
     TextView tv_right;
     public static Fg_right newInstance(String title){  
            Fg_right fg_right = new Fg_right();  
            Bundle b=new Bundle();
            b.putString("title", title);
            fg_right.setArguments(b);
            return fg_right;   
        }  
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
        View view= inflater.inflate(R.layout.fg_left, container, false);  
        Bundle arguments = this.getArguments();
        title=arguments.getString("title");
        this.tv_right = (TextView)view.findViewById(R.id.tv_right);  
        tv_right.setText(title);
        return view;
    }