Question

如何从列表视图本身单击项目时更新列表视图。我知道 notifydatachanged 但我不知道如何在我的代码中实现它以使其工作。请帮忙。

    private ListView listView;
private ArrayList<String> friends;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


  //initialize button ass and textview
    Button btnSearch = (Button)findViewById(R.id.btnSearch);

    final EditText ED = (EditText)findViewById(R.id.editText1);
    final TextView TV_word = (TextView)findViewById(R.id.TV_word);

    btnSearch.setOnClickListener(new OnClickListener()
    {
        @Override
        public void onClick(View arg0) {            
            String word = ED.getText().toString();
            fillFreinds(word);
            setUpList();
            TV_word.setText(word); //set the word into the textview which the user has entered into the search field
        }
    });


    //��� �������� ������
    ExternalDbOpenHelper dbOpenHelper = new ExternalDbOpenHelper(this, DB_NAME);
    database = dbOpenHelper.openDataBase();
    //���, ���� �������!

    fillWords();
    setUpList();
}

private void setUpList() 
{
    //��������� ����������� ������� � layout �������� ��� ���������
    setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, friends));
    listView = getListView();

    //������� ���� ����, ��� ����
    listView.setOnItemClickListener(new OnItemClickListener() 
    {
        public void onItemClick(AdapterView<?> parent, View view, int position,long id) 
        {               
            Toast.makeText(getApplicationContext(),((TextView) view).getText().toString(), Toast.LENGTH_SHORT).show();
            String wordClicked = ((TextView) view).getText().toString();
            fillFreinds(wordClicked);               
        }           
    });      
}

//���������� �������� �� ���� ������
private void fillFreinds(String word) {
    final TextView partOfspeech = (TextView)findViewById(R.id.tv_PartOfSpeech); 
    friends = new ArrayList<String>();

    Cursor friendCursor = database.rawQuery("SELECT * FROM friends where name='"+ word + "'", null);
    friendCursor.moveToFirst();

    if(!friendCursor.isAfterLast()) 
    {
        do 
        {
            String name = friendCursor.getString(2);
            partOfspeech.setText(friendCursor.getString(3));

            friends.add(name);
        } while (friendCursor.moveToNext());
    }

    friendCursor.close();
}
//On Start Activity
private void fillWords() {       
    friends = new ArrayList<String>();

    Cursor friendCursor = database.rawQuery("SELECT * FROM friends", null);
    friendCursor.moveToFirst();

    if(!friendCursor.isAfterLast()) 
    {
        do 
        {
            String name = friendCursor.getString(1);
            //partOfspeech.setText(friendCursor.getString(3));

            friends.add(name);
        } while (friendCursor.moveToNext());
    }
    friendCursor.close();
}

我谷歌一个小时，但我无法弄明白

Answer 1

将setUpList更改为以下代码：

private void setUpList() 
{
    //��������� ����������� ������� � layout �������� ��� ���������

     //// change to this
    adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, friends);
    setListAdapter(adapter);
    listView = getListView();

    //������� ���� ����, ��� ����
    listView.setOnItemClickListener(new OnItemClickListener() 
    {
        public void onItemClick(AdapterView<?> parent, View view, int position,long id) 
        {               
            Toast.makeText(getApplicationContext(),((TextView) view).getText().toString(), Toast.LENGTH_SHORT).show();
            String wordClicked = ((TextView) view).getText().toString();
            fillFreinds(wordClicked);

            /////  add following line
            adapter.notifyDatasetChanged();          

            /////
        }           
    });      
}

您还需要定义类的以下行顶部：

  ArrayAdapter<String> adapter;

要刷新数据，您可以使用notifyDatasetChanged();

Answer 2

在您的课程中添加此行

ArrayAdapter<String> adapter;

更改此行

setListAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, friends));

到

adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, friends)
setListAdapter(adapter);

并将适配器通知为

 adapter.notifyDataSetChanged();

即。将您的listView Item click功能更改为

 listView.setOnItemClickListener(new OnItemClickListener() 
    {
        public void onItemClick(AdapterView<?> parent, View view, int position,long id) 
        {               
            Toast.makeText(getApplicationContext(),((TextView) view).getText().toString(), Toast.LENGTH_SHORT).show();
            String wordClicked = ((TextView) view).getText().toString();
            fillFreinds(wordClicked);     
       adapter.notifyDataSetChanged();          
        }    


});

如何从列表视图本身单击项目时更新列表视图

2 个答案: