Android BroadcastReceiver : Unable to start and stop BroadcastReceiver, 手动，自动启动

Question

我为 Wi-Fi 创建了一个 brodcastReceiver，一切正常，除了，当我午餐应用程序时，broadcastreceiver 开始直接扫描，我无法停止它，即使我离开应用。我试图从主要 Activity 中控制广播接收器，但似乎存在问题。谁能看看我的代码，如果可能的话，告诉我可能是什么问题。

提前谢谢你。

PS :当点击按钮时，toasts起作用，但对广播接收者没有影响。

我正在 brodcastreceiver 中使用午餐服务，它会对问题产生影响吗？

                                  **EDIT** 

这是我的 MainActivity

    public class MainActivity extends Activity {
    int newRssi;
    List<String> listDebitDistance = new ArrayList<String>(); 
    WifiManager wifi;

    private final BroadcsatReceiverMnager broad = new BroadcsatReceiverMnager();
    ArrayList<int[]> listCursorReçue = new ArrayList<int[]>();
     IntentFilter rssiFilter = new          IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }




/**
 * This method enables the Broadcast receiver registered in the AndroidManifest file.
 * @param view
 */
    public void enableBroadcastReceiver(View view){
        switch (view.getId()){

        case R.id.button1 :

             super.registerReceiver(broad, new IntentFilter("android.intent.action.BOOT_COMPLETED"));

            this.registerReceiver(broad, rssiFilter);
            WifiManager wifiMan=(WifiManager)MainActivity.this.getSystemService(Context.WIFI_SERVICE);
            wifiMan.startScan();

          Toast.makeText(this, "Enabled broadcast receiver", Toast.LENGTH_SHORT).show();

            break; 
        }

        }
/**
* This method disables the Broadcast receiver registered in the AndroidManifest file.
* @param view
*/
public void disableBroadcastReceiver(View view){
    switch (view.getId()){

    case R.id.button2 :
        //this.unregisterReceiver(broad); //this gives the exception 
     unregisterReceiver(broad); //this methode gives the exception too
      Toast.makeText(this, "Disabled broadcst receiver", Toast.LENGTH_SHORT).show();


        break; 
    }

}

public void onPause() {

    super.onPause();
    this.unregisterReceiver(broad);
//S'il y a un appel l'app crash !!! a voir !!!!
}
/**
 * Broadcast receiver to update 
 */

public void onResume() {
    super.onResume();
   // BroadcsatReceiverMnager broad = new BroadcsatReceiverMnager();

    //Note: Not using RSSI_CHANGED_ACTION because it never calls me back.


    WifiManager wifiMan=(WifiManager)MainActivity.this.getSystemService(Context.WIFI_SERVICE);
    wifiMan.startScan();

}
}

这是我的 BroadcsatReceiverMnager 类

  public class BroadcsatReceiverMnager extends BroadcastReceiver {
    int newRssi;

     int rssi1 ;
   int rssi2;
   int rssi3 ;
   int rssiOp1=0  ;
    int rssiOp2 =0 ;
    int rssiOp3=0  ;
    WifiManager wifi;



    @Override
    public void onReceive(Context arg0, Intent arg1) {      
        Toast.makeText(arg0,"MyTag BroadcsatReceiverMnager "+ "onReceive", Toast.LENGTH_LONG).show();

        wifi = (WifiManager)arg0.getSystemService(Context.WIFI_SERVICE);

    if(arg1.getAction().equals(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION )){//
             List<ScanResult> results = wifi.getScanResults();
            Toast.makeText(arg0, "results"+results, Toast.LENGTH_SHORT).show();
            rssiOp1 =   results.get(0).level;
            rssiOp2 =   results.get(1).level;
            rssiOp3 =   results.get(2).level;

      }
     WifiManager wifiMan=(WifiManager)arg0.getSystemService(Context.WIFI_SERVICE);
      wifiMan.startScan();
      int newRssi = wifiMan.getConnectionInfo().getRssi();
      Toast.makeText(arg0, "BroadcsatReceiverMnager"+newRssi, Toast.LENGTH_SHORT).show();
}


}

Answer 1

如果你想控制你的接收者的注册和注销，根本不要在你的 list 中定义它。正如我在这个 answer 中所说的:

如果您在 list 中注册接收器，接收器的处理程序将在每次相应事件到来时启动。示例:每当您建立连接以向您显示通知时，facebook 的 Messenger 就会启动……或者当您连接以建议更新时，其他应用程序就会启动……换句话说，接收者始终处于注册状态。

在你的例子中，在你的 Activity 中定义接收者，在同一个 Activity 中注册和注销它。

/**
 * the intent of communication with the Brodcast receiver
 */
IntentFilter intentFilter = new IntentFilter();



/**
 * the BroadcastReceiver 
 */
BroadcastReceiver yourBroadcastReceiver = new BroadcsatReceiverMnager ();

在你的 onCreat() 中:

// set the action
intentFilter.addAction("SCAN_RESULTS_AVAILABLE_ACTION");

注册它:

    registerReceiver(yourBroadcastReceiver , intentFilter);

取消注册:

unregisterReceiver(yourBroadcastReceiver);

因此，在您的听众中:

    /**
 * This method enables the Broadcast receiver registered in the AndroidManifest file.
 * @param view
 */
    public void enableBroadcastReceiver(View view){
        switch (view.getId()){

        case R.id.button1 :

           registerReceiver(yourBroadcastReceiver , intentFilter);

              Toast.makeText(this, "Enabled broadcast receiver", Toast.LENGTH_SHORT).show();

            break; 
        }

        }
/**
* This method disables the Broadcast receiver registered in the AndroidManifest file.
* @param view
*/
public void disableBroadcastReceiver(View view){
    switch (view.getId()){

    case R.id.button2 :

        unregisterReceiver(yourBroadcastReceiver);

          Toast.makeText(this, "Disabled broadcst receiver", Toast.LENGTH_SHORT).show();


        break; 
    }

}

您在评论中最后一个问题的答案:

1/您需要进行扫描以获取一些信息。

2/你只想在主要 Activity 中通过操作(通过 Intent 过滤器)来午餐扫描。

===> 您在此 Activity 中使用接收器:- 在 onResume() 中注册并在 onPause() 中取消注册- 在接收器的 onReceive() 中进行扫描(以及您想对它将返回的数据执行的操作)。

3/您想管理何时激活接收器，何时禁用它:接收器不仅取决于 Activity 的生命周期:===> 然后添加一个按钮来激活或禁用它(注册/注销)。