Question

我在一个片段上显示了一些数据，每次点击一个按钮，它都应该添加到第二个片段中的listView。出于某种原因，当我点击按钮时，listView不会改变。

fragment1：

nextButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) 
                {            
                    HistoryFragment.addToHistory( myObject );
                }});

HistoryFragment（listView）：

public class HistoryFragment extends ListFragment
{ 
    private static List<Password> historyList = new ArrayList<MyObject>();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        historyList = myManager.getMyObjects ();
    }

    public static void addToHistory( MyObject myObject )
    {
        historyList.add( myObject );
    }

  @Override
  public View onCreateView(LayoutInflater inflater, ViewGroup         container, Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.fragment_history, container, false);
    MyObjectAdapter adapter = new MyObjectAdapter( historyList );
    setListAdapter(adapter);
    return view;
}
    ....
    ....
    ....
private class MyObjectAdapter extends BaseAdapter
    {
        private final ArrayList<MyObject> data; 

        public MyObjectAdapter( List<MyObject> historyList ) 
        {
            data = new ArrayList<MyObject>();
            data.addAll( historyList );
        }

        @Override
        public int getCount() 
        {
            return data.size();
        }

        @Override
        public MyObject getItem( int position ) 
        {            
            return data.get( position );
        }

        @Override
        public long getItemId(int position) {
            // TODO implement you own logic with ID
            return 0;
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            final View result;

            notifyDataSetChanged();

            if (convertView == null) 
            {
                result = LayoutInflater.from(parent.getContext()).inflate(R.layout.history_list_item, parent, false);
            } 
            else 
            {
                result = convertView;
            }

            MyObject item = getItem( position );

            ( (TextView) result.findViewById(R.id.historyObjectTextView) ).setText(item.toString());

            return result;
       }
    }

片段main（1）：

  public class MainFragment extends Fragment 
 {
 Map<String,MyObject> objects  = new HashMap<String,MyObject>();
 List< MyObject > objectsList = new ArrayList< MyObject >();
 TextView nextDisplay;

@Override
 public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
objects = myManager.getInstance().getObjects();
objectsList = MyObject.getObjectsList();
}

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

nextDisplay = ( TextView ) view.findViewById( R.id.displayTextView );
nextDisplay.setText( objectsList.get( 0 ).getObjectString() );

Button nextButton = ( Button ) view.findViewById( R.id.nextObjectButton );
nextButton.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) 
        {            
            if( objectsList.size() > 0 )
            {
                objects.get(objectsList.get( 0 ).getObjectString()).setTried( true );
                long currentTime = System.currentTimeMillis();
                objects.get(objectsList.get( 0 ).getObjectString()).setTime( currentTime );


                HistoryFragment.addToHistory( objectsList.get( 0 ) );
                objectsList.remove( 0 );

                if( objectsList.size() > 0  && !objectsList.get( 0 ).getTried() )
                {
                    nextCodeDisplay.setText( objectsList.get( 0 ).getObjectString() );
                }
            }           
        }});
return view;

}

Answer 1

喜欢这个。

private List<Password> historyList = new ArrayList<MyObject>();
private MyObjectAdapter adapter
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.fragment_history, container, false);
    adapter = new MyObjectAdapter( historyList );
    setListAdapter(adapter);
    return view;
}

private static List<Password> historyList = new ArrayList<MyObject>();

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    historyList = myManager.getMyObjects ();
}

public void addToHistory( MyObject myObject )
{
    historyList.add( myObject );
    adapter.notifyDataSetChanged();
}

Answer 2

尝试在OnClickListener上调用notifyDataSetChanged()：

nextButton.setOnClickListener(new View.OnClickListener() {
                public void onClick(View v) 
                {            
                    HistoryFragment.addToHistory( myObject );
                    notifyDataSetChanged();
                }});

ListView不会自行更新

2 个答案: