Question

如果我在与ListView关联的自定义适配器上调用notifyDataSetChanged()，则所有视图都应自行刷新（getView()将被调用）。现在我有一个正在收听事件的BroadcastReceiver。触发事件时，必须刷新ListView。我怎样才能做到这一点？谢谢！

Answer 1

如果您从接收器刷新listview，您将拥有以下代码：

BroadcastReceiver br;
public final static String BROADCAST_ACTION = "BROADCAST_ACTION";
br = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
//code refreshing...
}
};
IntentFilter intFilt = new IntentFilter(BROADCAST_ACTION);
registerReceiver(br, intFilt);

你用代码称呼它：

Intent intent = new Intent(BROADCAST_ACTION);
sendBroadcast(intent);

如果您需要刷新为另一个操作，您只需添加（操作后）：

Intent intent = new Intent(BROADCAST_ACTION);
sendBroadcast(intent);

Answer 2

根据要求，请参阅以下示例代码：

public interface OnDataUpdateListener {
    void onDataAvailable(ArrayList<String> newDataList);
}

public class MyTestReceiver extends BroadcastReceiver {
    public static final String DATA_LIST = "DATA_LIST";
    private OnDataUpdateListener mDataUpdateListener = null;
    public MyTestReceiver(OnDataUpdateListener dataUpdateListener) {
        mDataUpdateListener = dataUpdateListener;
    }

    @Override
    public void onReceive(Context ctx, Intent intent) {
        // assuming data is available in the delivered intent
        ArrayList<String> dataList = intent.getSerializableExtra(DATA_LIST);
        if (null != mDataUpdateListener) {
            mDataUpdateListener.onDataAvailable(dataList);
        }
    }
}

public class MyActivity extends FragmentActivity implements OnDataUpdateListener {
    public static final String ACTION_DATA_UPDATE_READY = "ACTION_DATA_UPDATE_READY";
    private MyTestReceiver mTestReceiver = null;
    private <SomeAdapterClass> mAdapter = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // other required initialization 
        mTestReceiver = new MyTestReceiver(this);
    }

    @Override
    public void onResume() {
        super.onResume();
        if (null != mTestReceiver) {
            registerReceiver(mTestReceiver, new IntentFilter(ACTION_DATA_UPDATE_READY));
        }
    }

    void onDataAvailable(ArrayList<String> newDataList) {
        // assuming you want to replace existing data and not willing to append to existing dataset
        mAdapter.clear();
        mAdapter.addAll(newDataList);
        mAdapter.notifyDataSetChanged();
    }
}

Answer 3

在更新数据的代码中，触发一条消息，表明数据已被更改... （您需要访问Activity或Application上下文才能执行此操作）

Intent intent = new Intent("ListViewDataUpdated");
LocalBroadcastManager.getInstance(context.sendBroadcast(intent));

然后在您的活动中使用以下代码捕获消息，并告诉ListAdapter更新...

private BroadcastReceiver mMessageReceiver = new BroadcastReceiver() {
          @Override
          public void onReceive(Context context, Intent intent) {
            myListAdapter.notifyDataSetChanged();
           }
        };

@Override
public void onResume(){
  super.onResume();
  LocalBroadcastManager.getInstance(this).registerReceiver(mMessageReceiver, new IntentFilter("ListViewDataUpdated"));
  myListAdapter.notifyDataSetChanged();//in case our data was updated while this activity was paused
}


@Override
protected void onPause() {
   LocalBroadcastManager.getInstance(this).unregisterReceiver(mMessageReceiver);
   super.onPause();
}

信用：改编自Vogella

Answer 4

LocalBroadcastManager.getInstance(context.sendBroadcast(intent));

改为

LocalBroadcastManager.getInstance(context).sendBroadcast(intent);

我可能错了，但它对我有用...

如何从BroadcastReceiver刷新ListView？

4 个答案: