如何在扩展BroadcastReceiver的类中注册广播接收器？

Posted 2021-04-09

我已经看到了关于BroadcastReceiver注册的所有例子，所有这些例子都注册了接收器而没有扩展BroadcastReceiver类。但我有以下代码

package vertex2016.mvjce.edu.bluealert;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.UUID;

public class SearchBLDev extends BroadcastReceiver {

    private BluetoothAdapter BTAdapter = BluetoothAdapter.getDefaultAdapter();
    private ArrayAdapter BTArrayAdapter;
    private ListView BTListView;
    private BluetoothDevice BTD;
    public UUID myUUID;

    IntentFilter filter = new IntentFilter();

    public void discoveryStart()
    {
        filter.addAction(BluetoothDevice.ACTION_FOUND);
        filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
        filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
        registerReceiver(SearchBLDev, filter) //PROBLEM OCCURS HERE        
    }

    @Override
    public void onReceive(Context context, Intent intent)
    {}
}

我可以使用registerReceiver方法注册一个Receiver。它显示错误。

感谢您的时间。

答案

您需要一个Context来调用registerReceiver(this, filter)，因此您应该将其作为参数传递。

public void discoveryStart(Context context)
{
    filter.addAction(BluetoothDevice.ACTION_FOUND);
    filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_STARTED);
    filter.addAction(BluetoothAdapter.ACTION_DISCOVERY_FINISHED);
    context.registerReceiver(this, filter) //PROBLEM OCCURS HERE
}

然后你可以从你的Activity调用它：

SearchBLDev broadcastReceiver = new SearchBLDev();
broadcastReceiver.discoveryStart(this);

另一答案

您是否尝试将接收器添加到清单中？你在哪里初始化这个broadcastReceiver？