如何從另一個活動調用不同活動的函數

Question

我想從TimePickerPopup類的onClick函數中調用MainFragmentActivity2類中的函數populateTimeList（）。我該怎麼做？這些是分別的代碼。我對android非常陌生，請幫忙！

public class MainActivityFragment2 extends Fragment { 

private List<TimeList> TDList = new ArrayList<TimeList>(); 

public MainActivityFragment2() { 
} 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
} 

private void populateTimeList() { 
    Context ctx = this.getActivity(); 
    DBoperations db = new DBoperations(ctx); 
    Cursor cr = db.getInformation(db); 
    cr.moveToFirst(); 
    String TimeH, TimeM, EtimeH, EtimeM; 
    do { 
     TimeH = Integer.toString(cr.getInt(1)); 
     TimeM = Integer.toString(cr.getInt(2)); 
     EtimeH = Integer.toString(cr.getInt(3)); 
     EtimeM = Integer.toString(cr.getInt(4)); 
     TDList.add((new TimeList(TimeH + " : " + TimeM, EtimeH + " : " + EtimeM))); 
    }while (cr.moveToNext()); 
} 

private class MyAdapter extends ArrayAdapter<TimeList> { 

    public MyAdapter(Context context, List<TimeList> values) { 

     super(context, R.layout.time_list_item,values); 
    } 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 

     View v = convertView; 
     LayoutInflater inflater = LayoutInflater.from(getContext()); 

     if(v == null){ 
      v = inflater.inflate(R.layout.time_list_item, parent, false); 
     } 

     TimeList currLoc = TDList.get(position); 

     TextView theTextView = (TextView) v.findViewById(R.id.time_list_item_textview1); 
     theTextView.setText(currLoc.getTime()); 

     theTextView = (TextView) v.findViewById(R.id.time_list_item_textview2); 
     theTextView.setText(currLoc.getDuration()); 

     return v; 
    } 
} 

@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    View rootView = inflater.inflate(R.layout.time_list_view, container, false); 

    ListView list = (ListView) rootView.findViewById(R.id.time_list_view); 
    final ArrayAdapter<TimeList> adapter = new MyAdapter(getActivity(),TDList); 
    list.setAdapter(adapter); 
    populateTimeList(); 
    setRetainInstance(true); 

    ImageButton ib = (ImageButton) rootView.findViewById(R.id.imageButton1); 
    ib.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      startActivity(new Intent(MainActivityFragment2.this.getActivity(), TimePickerPopup.class)); 
     } 
    }); 

    return rootView; 
} 
} 

而且

public class TimePickerPopup extends Activity { 

private List<TimeList> TDList = new ArrayList<TimeList>(); 
Context ctx =this; 

private TimePicker time_picker1; 
private TimePicker time_picker2; 
private ImageButton select_time1; 
private ImageButton select_time2; 

@Override 
public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 

    setContentView(R.layout.time_picker); 

    DisplayMetrics dm = new DisplayMetrics(); 
    getWindowManager().getDefaultDisplay().getMetrics(dm); 

    int width = dm.widthPixels; 
    int height = dm.heightPixels; 

    getWindow().setLayout((int) (width * .8), (int) (height * .7+50)); 

    time_picker1 = (TimePicker) findViewById(R.id.timePicker1); 
    time_picker2 = (TimePicker) findViewById(R.id.timePicker2); 
    select_time1 = (ImageButton) findViewById(R.id.selectButton1); 
    select_time2 = (ImageButton) findViewById(R.id.selectButton2); 

    select_time1.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Toast.makeText(getBaseContext(), "Start time " + time_picker1.getCurrentHour() + " : " + time_picker1.getCurrentMinute(), Toast.LENGTH_SHORT).show(); 
      ScrollView sv1 = (ScrollView) findViewById(R.id.sv); 
      sv1.fullScroll(View.FOCUS_DOWN); 
     } 
    }); 

    select_time2.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Toast.makeText(getBaseContext(),"End time " + time_picker2.getCurrentHour() + " : " + time_picker2.getCurrentMinute(), Toast.LENGTH_SHORT).show(); 
      DBoperations db = new DBoperations(ctx); 
      db.putInfo(db, time_picker1.getCurrentHour(), time_picker1.getCurrentMinute(), time_picker2.getCurrentHour(), time_picker2.getCurrentMinute(), 0, 0); 
      finish(); 
     } 
    }); 
} 
} 

基本上，我想從TimePickerPopup類數據庫剛剛輸入的數據在ListView露面（即刷新我的列表視圖）。目前它顯示了我關閉然後啓動我的應用程序後輸入的新數據。

Answer 1

在你的xml文件裏面添加<fragment>標籤。

android:tag="any_tag" 

爲了得到一個片段的當前對象做到這一點在Java文件（在你的TimePickerPopup.java的onClick（視圖v）方法添加此）

MainActivityFragment2 ma2 = (MainActivityFragment2) getFragmentManager().findFragmentByTag("any_tag"); 
ma2.populateTimeList();