适配器数据更改时更新列表视图

Question

当更改与数组适配器关联的数据时,使listview无效就足以显示更新的值？下面的代码不起作用,我在这里误解了什么.

public class ZeroItemListActivity extends Activity {
    private ArrayList<String> listItems=new ArrayList<String>();
    private ListView mMyListView;
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mMyListView=(ListView) findViewById(R.id.MyListView);
        mMyListView.setAdapter(new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1,listItems));
    }
    public void addItem(View v){
        listItems.add("list Item");
        mMyListView.invalidate();
    }
}

使用的布局:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="fill_parent"
    android:layout_height="fill_parent">
    <TextView android:layout_width="fill_parent"
        android:layout_height="wrap_content" android:text="@string/hello" />
    <ListView android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:id="@+id/MyListView"></ListView>
    <Button android:layout_width="wrap_content"
        android:layout_height="wrap_content" android:id="@+id/AddItemsButton"
        android:text="Add Items" android:onClick="addItem"></Button>
</LinearLayout>

Answer 1

替代:

mMyListView.invalidate();

对于:

((BaseAdapter) mMyListView.getAdapter()).notifyDataSetChanged(); 

如果这不起作用,请参阅此线程: Android列表视图刷新

Answer 2

改变这一行:

mMyListView.setAdapter(new ArrayAdapter<String>(this, 
                           android.R.layout.simple_list_item_1, 
                           listItems));

至:

ArrayAdapter<String> adapter = new ArrayAdapter<String>(this,
                                   android.R.layout.simple_list_item_1, 
                                   listItems)
mMyListView.setAdapter(adapter);

并在更新列表项的值后,调用:

adapter.notifyDataSetChanged();