SimpleAdapter notifyDataSetChanged

Question

每当我删除ListView上的项目时，我都会尝试刷新它。但是设置一个notifyDataSetChanged();会给我带来这个错误：

不能引用在不同方法中定义的内部类中的非最终变量适配器。

方法notifyDataSetChanged()未为ListAdapter类型定义。

ArrayList <HashMap <String, String> > data = dataHolder.getAllData();
dataHolder.getAllData();

if(data.size() !=0){

ListView lv = (ListView) findViewById(R.id.datalist);
ListAdapter adapter = new SimpleAdapter(MainActivity.this, data, R.layout.dataentry, new String[]{"unique_id","lastName"}, new int[]{R.id.unique_id,R.id.last_name});
lv.setAdapter(adapter);
lv.setOnItemLongClickListener(new OnItemLongClickListener() {

                @Override
                public boolean onItemLongClick(AdapterView<?> arg0, View arg1,
                        int arg2, long arg3) {

                    AlertDialog.Builder adb = new AlertDialog.Builder(MainActivity.this);
                    adb.setTitle("Delete?");
                    adb.setIcon(android.R.drawable.ic_dialog_alert);
                    adb.setMessage("Delete selected item?");
                    adb.setCancelable(false);
                    adb.setNegativeButton("Cancel", null);
                    adb.setPositiveButton("Delete", new AlertDialog.OnClickListener() {

                    public void onClick(DialogInterface dialog, int which) {

                        TextView uID = (TextView) findViewById(R.id.unique_id);
                        String unique_id = uID.getText().toString();
                        dataHolder.deleteData(unique_id);
                        adapter.notifyDataSetChanged();
                    }
                });  
                adb.show();
                return false;
                }
            });
}

然后建议将其改为：

((BaseAdapter) adapter).notifyDataSetChanged();

final ListAdapter adapter = new SimpleAdapter(MainActivity.this, data, R.layout.dataentry, new String[]{"unique_id","lastName"}, new int[]{R.id.unique_id,R.id.last_name});

但这并不是在更改列表之后刷新列表。解决这个问题的办法是什么？

Answer 1

找到解决办法了。必须先从列表视图的数组列表中删除该项，然后才能通知更改的数据集。

data.remove(position);
adapter.notifyDataSetChanged();

Answer 2

要从adapter中引用AlertDialog.OnClickListener，you need it to be final (这基本上就是错误告诉您的)。所以只需声明它final

final BaseAdapter adapter = new SimpleAdapter(MainActivity.this, data, R.layout.dataentry, new String[]{"unique_id","lastName"}, new int[]{R.id.unique_id,R.id.last_name});

您还可以从调用它的参数中获取它：

@Override
public boolean onItemLongClick(final AdapterView<?> adapterView, View arg1, int arg2, long arg3) {
    // ...
    final Adapter adapter = adapterView.getAdapter();
    if (adapter instanceof BaseAdapter) {
        ((BaseAdapter)adapter).notifyDataSetChanged();
    } else {
        throw new RuntimeException("Unexpected adapter");
    }

例如。

Answer 3

只需将ListAdapter声明为全局变量即可