在 MainActivity 中调用方法和变量 class

Question

我想将内部 BroadcastReceiverListener 放在 MainActivity 中，它在那里工作得很好，在 serperate class 中。我不知道如何从 MainActivity 调用方法 "deliverBestAccessPoint(updatedResults)" 并从 BroadcastReceiverListener 在 MainActivity 中设置变量 "textWifi" 的问题。我该如何管理？我希望有人能用代码回答以理解他的答案。

感谢任何帮助。

private class BroadcastReceiverListener extends BroadcastReceiver {
  @Override
  public void onReceive(Context context, Intent intent) {
   if (intent.getAction().equals(
     android.net.wifi.WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {
 if (intent.getAction().equals(
   android.net.wifi.WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {

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

  WifiManager wifiManager = (WifiManager) context
    .getSystemService(Context.WIFI_SERVICE);
  final List<ScanResult> results = wifiManager.getScanResults();
  if (results != null) {
   // list of access points from the last scan
   List<ScanResult> updatedResults = new ArrayList<ScanResult>();
   // pick Wi-Fi access points which begins with these "SV-"
   // characters.
   for (int i = 0; i < results.size(); i++) {
    String ssid = results.get(i).SSID;
    // Pattern p = Pattern.compile("^KD-(4[0-9]{2}|500)$");
    // Matcher m = p.matcher(ssid);
    // if(m.matches()){}else{}
    if (ssid.startsWith("KD")) {

     updatedResults.add(results.get(i));
    } else {
     textWifi.setText("No route is available.");

    }
   }
   if (updatedResults.size() > 0) {
    String a = deliverBestAccessPoint(updatedResults);
    textWifi.setText(a.toString());
   }
  } else {
   textWifi.setText("There is no WiFi in range.");

  }

  Intent updateIntent = new Intent(context, MainActivity.class);
  updateIntent.putExtra("broadcast_event", updatedResults);
  context.startActivity(intent);

 }
}

   else if (intent.getAction().equals(
     android.net.ConnectivityManager.CONNECTIVITY_ACTION)) {
    
   }
  }

Answer 1

一种方法是将 Intent 从您的广播接收器发送到 activity:

编辑

最后应该是这样的。但我没有具体说明如何将自定义对象列表转换为 JSON 数组并返回，这是一个完全独立的问题，有其自身的潜在困难。您可以弄清楚如何使用标准转换器或使用某些库来完成此操作。我个人更喜欢 GSON, it deals 不需要你付出太多努力就可以很好地处理对象集合。

public class BroadcastReceiverListener extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals(
                android.net.wifi.WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {
            if (intent.getAction().equals(
                    android.net.wifi.WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {

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

                WifiManager wifiManager = (WifiManager) context
                        .getSystemService(Context.WIFI_SERVICE);
                final List<ScanResult> results = wifiManager.getScanResults();
                if (results != null) {
                    // list of access points from the last scan
                    List<ScanResult> updatedResults = new ArrayList<ScanResult>();
                    // pick Wi-Fi access points which begins with these "SV-"
                    // characters.
                    for (int i = 0; i < results.size(); i++) {
                        String ssid = results.get(i).SSID;
                        // Pattern p = Pattern.compile("^KD-(4[0-9]{2}|500)$");
                        // Matcher m = p.matcher(ssid);
                        // if(m.matches()){}else{}
                        if (ssid.startsWith("KD")) {
                            updatedResults.add(results.get(i));
                        }
                    }
                    Intent updateIntent = new Intent(context, MainActivity.class);
                    String extras = convertToJson(updatedResults);
                    updateIntent.putExtra("broadcast_event", extras);
                    context.startActivity(intent);
                }
            }
        } else if (intent.getAction().equals(
                android.net.ConnectivityManager.CONNECTIVITY_ACTION)) {
        }
    }
}

public class YourActivity extends Activity {
    ...
    @Override
    protected void onNewIntent(Intent intent) {
        String resultsJson = intent.getStringExtra("broadcast_event");
        if (resultsJson != null) {
            List<ScanResult> results = convertFromJson(resultsJson);
            String a = deliverBestAccessPoint(results);
            textWifi.setText(a.toString());
        } else {
            textWifi.setText("No route is available.");
        }
    }
}

Answer 2

另一种方法是将 MainActivity 添加为 BroadcastReceiver 的 WeakReference 成员：

private class BroadcastReceiverListener extends BroadcastReceiver {

    public BroadcastReceiverListener (MainActivity mainActivity){
           mainActivityRef = new WeakReference<>(mainActivity);
    }

    private WeakReference<MainActivity> mainActivityRef;
                @Override
                public void onReceive(Context context, Intent intent) {
                    if (intent.getAction().equals(
                            android.net.wifi.WifiManager.SCAN_RESULTS_AVAILABLE_ACTION)) {

                                  // This method"deliverBestAccessPoint" is in MainActivity class
    MainACtivity mActivity = mainActivityRef.get();
    if(mActivity != null){//could be collected by GC
                                String a = mActivity .deliverBestAccessPoint(updatedResults);
                                //I want to set the "textwifi" varaible in MainActivity
                                mActivity.textWifi.setText(a.toString());
        }
                            }

                    }

                    else if (intent.getAction().equals(
                            android.net.ConnectivityManager.CONNECTIVITY_ACTION)) {

                    }
                }

并且在 MainActivity 中注册时：registerReceiver(new BroadcastReceiverListener (this), mIntentFilter);

在 MainActivity 中调用方法和变量 class

call method and Variable in the MainActivity class

android

broadcastreceiver