SherlockFragemtActivity選項卡無法將數據放入列表視圖

我正在學習關於Sherlock ActionBar的開發，我創建了一個使用Sherlock ActionBar將示例程序填充到數據庫的日期列表。SherlockFragemtActivity選項卡無法將數據放入列表視圖

因爲我在一個活動中創建了兩個選項卡，我用來輸入細節的第一個選項卡（fragment1）工作正常，但需要將數據填充到listview中的第二個選項卡（fragment2）不是工作正常。

請看看我的代碼：

Fragment2.java爲DATABSE

public class Fragment2 extends SherlockFragment implements TabListener { 
    private Fragment mFragment; 

    DBAdapter db; 
    Cursor c; 
    ListView list; 
    MyAdapter myAdapter; 
    View view ; 

    Context context; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onCreate(savedInstanceState); 
     //getActivity().setContentView(R.layout.details_listview); 

     db = new DBAdapter(getActivity()); 
     db.openDatabase(); 
    } 

    @Override 
    public View onCreateView(LayoutInflater inflater, ViewGroup container, 
      Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     view = inflater.inflate(R.layout.details_listview, null); 
     return view; 
    } 

    @Override 
    public void onActivityCreated(Bundle savedInstanceState) { 
     // TODO Auto-generated method stub 
     super.onActivityCreated(savedInstanceState); 

     list = (ListView)view.findViewById(R.id.listView1); 
      registerForContextMenu(list); 
     updateListView(); 
    } 

    private void updateListView() { 
     // TODO Auto-generated method stub 
     c = db.getAllRecords(); 
     myAdapter = new MyAdapter(); 
     list.setAdapter(myAdapter); 
    } 

    @Override 
    public void onTabSelected(Tab tab, FragmentTransaction ft) { 
     // TODO Auto-generated method stub 

     mFragment = new Fragment2();   
      ft.add(android.R.id.content, mFragment); 
      ft.attach(mFragment); 
    } 

    @Override 
    public void onTabUnselected(Tab tab, FragmentTransaction ft) { 
     // TODO Auto-generated method stub 
     ft.remove(mFragment); 
    } 

    @Override 
    public void onTabReselected(Tab tab, FragmentTransaction ft) { 
     // TODO Auto-generated method stub 

    } 

    class MyAdapter extends BaseAdapter{ 

     Context context; 

     @Override 
     public int getCount() { 
      // TODO Auto-generated method stub 
      return c.getCount(); 
     } 

     @Override 
     public Object getItem(int arg0) { 
      // TODO Auto-generated method stub 
      return null; 
     } 

     @Override 
     public long getItemId(int arg0) { 
      // TODO Auto-generated method stub 
      return 0; 
     } 

     @Override 
     public android.view.View getView(int position, android.view.View conview, 
       ViewGroup arg2) { 
      LayoutInflater inflater = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
      conview = inflater.inflate(R.layout.customllistview, null); 

      TextView t1 = (TextView)conview.findViewById(R.id.idtextView); 
      TextView t2 = (TextView)conview.findViewById(R.id.nametextView); 
      TextView t3 = (TextView)conview.findViewById(R.id.locationtextView); 

      c.moveToPosition(position); 

      String id = c.getString(0); 
      String name = c.getString(1); 
      String location = c.getString(2); 

      t1.setText("row id: "+id); 
      t2.setText("name :"+name); 
      t3.setText("location :"+location); 


      return conview; 
     } 

    } 

}

DATABSE適配器： DBAdapter.java

public class DBAdapter { 

    DBHelper dbHelper; 
    Context context; 
    SQLiteDatabase db; 
    public static final int DATABASE_VERSION = 1; 

    String DATABASE_NAME = "sampleDB"; 
    String TABLE_NAME = "sample"; 

    String COL_ROWID = "rowid"; 
    String COL_NAME ="name"; 
    String COL_LOCATION = "location"; 

    String CREATE_TABLE = "create table sample(rowid integer primary key autoincrement,name text not null,location text not null) "; 

    public DBAdapter(Context c) { 
     // TODO Auto-generated constructor stub 
     this.context = c; 
     dbHelper = new DBHelper(context); 
    } 

    DBAdapter openDatabase() { 
     db = dbHelper.getWritableDatabase(); 
     return this; 

    } 

    void close() { 
     dbHelper.close(); 
    } 

    long insertRecord(String name, String location) { 
     ContentValues con = new ContentValues(); 
     con.put(COL_NAME, name); 
     con.put(COL_LOCATION, location); 

     return db.insert(TABLE_NAME, null, con); 

    } 

    Cursor getAllRecords(){ 
     String[] columns = {COL_ROWID,COL_NAME,COL_LOCATION}; 
     return db.query(TABLE_NAME, columns, null, null, null, null, null); 

    } 

    class DBHelper extends SQLiteOpenHelper { 

     public DBHelper(Context context) { 
      super(context, DATABASE_NAME, null, DATABASE_VERSION); 
      // TODO Auto-generated constructor stub 
     } 

     @Override 
     public void onCreate(SQLiteDatabase db) { 
      // TODO Auto-generated method stub 
      db.execSQL(CREATE_TABLE); 
     } 

     @Override 
     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { 
      // TODO Auto-generated method stub 

     } 

    } 


}

最後這裏是我的logcat的輸出：

07-22 18:54:16.684: E/AndroidRuntime(1204): FATAL EXCEPTION: main 
07-22 18:54:16.684: E/AndroidRuntime(1204): java.lang.NullPointerException 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at com.example.sherlocklistview.Fragment2$MyAdapter.getView(Fragment2.java:111) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.AbsListView.obtainView(AbsListView.java:1430) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.ListView.measureHeightOfChildren(ListView.java:1216) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.ListView.onMeasure(ListView.java:1127) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.View.measure(View.java:8313) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1017) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.LinearLayout.measureHorizontal(LinearLayout.java:701) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:311) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.View.measure(View.java:8313) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.View.measure(View.java:8313) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.View.measure(View.java:8313) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.LinearLayout.measureVertical(LinearLayout.java:531) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.LinearLayout.onMeasure(LinearLayout.java:309) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.View.measure(View.java:8313) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.View.measure(View.java:8313) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:3138) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.widget.FrameLayout.onMeasure(FrameLayout.java:250) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.View.measure(View.java:8313) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.ViewRoot.performTraversals(ViewRoot.java:839) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.view.ViewRoot.handleMessage(ViewRoot.java:1859) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.os.Handler.dispatchMessage(Handler.java:99) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.os.Looper.loop(Looper.java:123) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at android.app.ActivityThread.main(ActivityThread.java:3683) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at java.lang.reflect.Method.invokeNative(Native Method) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at java.lang.reflect.Method.invoke(Method.java:507) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597) 
07-22 18:54:16.684: E/AndroidRuntime(1204):  at dalvik.system.NativeStart.main(Native Method)

請爲我的問題提供一些解決方案

來源

2013-07-22 Seenu69

不確定在你的代碼中是否有其他問題，但MyAdapter中的'context'變量爲空。 – Vikram

@Vikram，你是對的我已經添加了MyAdapter的參數來使它工作。 – Seenu69

請提供有關哪一行與您的文件Fragment2.java中的111行完全相同（考慮到導入行號）的信息。
在Fragment2.java中的MyAdapter中檢查您的上下文變量，因爲它看起來像沒有在任何地方初始化。

來源

2013-07-22 13:49:05 AitorTheRed

Blow是第111行的代碼：LayoutInflater inflater =（LayoutInflater）context.getSystemService（Context.LAYOUT_INFLATER_SERVICE）; – Seenu69

SherlockFragemtActivity選項卡無法將數據放入列表視圖

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