应用程序永远不会收到RSSI_CHANGED_ACTION [英] Application never receives RSSI_CHANGED_ACTION

问题描述

我是Android编程的新手，正在尝试了解BroadcastReceivers的概念.为了帮助自己，我正在尝试编写一个监视Wifi信号强度的小型应用程序.

I am new to Android programming and am trying to understand the concept of BroadcastReceivers. In order to help myself, I am just trying to write a small application that monitors Wifi signal strength.

现在，据我了解，我可以等待接收系统广播的RSSI_CHANGED_ACTION.RSSI应该经常更改，这意味着我应该经常收到此通知...但是，我永远不会收到一次.我已经将代码减少到最低限度，因此它仅在收到通知时记录一条消息.

Now, from my understanding I can simply wait to receive the RSSI_CHANGED_ACTION broadcasted by the system. The RSSI should change frequently which means I should be receiving this notification frequently...however, never do I receive it once. I have watered my code down to the bare minimum so it just logs a message when the notification is received.

public class RssiActivity extends Activity {

    public BroadcastReceiver rssiReceiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            // TODO Auto-generated method stub
            Log.d("Rssi", "RSSI changed");
        }
    };

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    @Override
    public void onResume() {
        super.onResume();
        registerReceiver(rssiReceiver, new IntentFilter(WifiManager.RSSI_CHANGED_ACTION));
        Log.d("Rssi", "Registered");
    }

    @Override
    public void onPause() {
        super.onPause();
        unregisterReceiver(rssiReceiver);
        Log.d("Rssi", "Unregistered");
    }
}

我已经看过这篇文章 Android:如何监控WiFi信号强度，但似乎对我没有帮助.我还在 http:上尝试过代码示例://android-er.blogspot.com/2011/01/check-rssi-by-monitoring-of.html ，并且它也从未更新过RSSI值.我很困惑为什么会这样.您能给我的任何帮助将不胜感激.谢谢！

I have already seen this post Android: How to monitor WiFi signal strength and it doesn't seem to help me. I have also tried the code sample here http://android-er.blogspot.com/2011/01/check-rssi-by-monitoring-of.html and it never updated the RSSI value either. I'm quite confused as to why this is. Any help you can give me would be greatly appreciated. Thanks!

推荐答案

因此，我遇到了与您相同的问题，因为当用户走动时想要一个更新的RSSI值，等等，而我无法使用RSSI_CHANGED_ACTION来解决它

So, I had the same problem that you did, wanting to an updated RSSI value as the user walked around, etc, and I could not solve it using RSSI_CHANGED_ACTION.

就像您遇到的问题一样，无法正确调用我的回调.奇怪的是，在创建活动时只调用了一次，然后再也没有调用它.

Like the issue you're having, my callback would not be called correctly. Strangely, it was only called once, when the activity was created, and then never again.

在您的onCreate()中，为SCAN_RESULTS_AVAILABLE_ACTION注册一个回调.然后调用WifiManager.startScan().

In your onCreate(), register a callback for SCAN_RESULTS_AVAILABLE_ACTION. Then call WifiManager.startScan().

现在，在您的回调中，执行以下操作:

Now, in your callback, do:

WifiManager wifiMan=(WifiManager)getActivity().getSystemService(Context.WIFI_SERVICE);
int newRssi = wifiMan.getConnectionInfo().getRssi();
wifiMan.startScan();

现在您有一个循环，在该循环中，回调将启动扫描，接收结果，然后启动另一扫描.

Now you have a loop, where the callback initiates a scan, receives the results, and initiates another scan.

这很重要，并且会消耗很多功率，但是，您可以在走动时观察RSSI值的变化.

It's gross and will suck a lot of power, however, you can watch the RSSI values change as you walk around.

(请注意，我使用onResume和onPause进行注册和注销，因此只会在屏幕上显示活动时重复扫描，例如，废电池)

(note that I use onResume and onPause to register and unregister, so it will only scan repeatedly, e.g. waste battery, when the activity is onscreen)

@Override
public void onResume() {
    super.onResume();
    //Note: Not using RSSI_CHANGED_ACTION because it never calls me back.
    IntentFilter rssiFilter = new IntentFilter(WifiManager.SCAN_RESULTS_AVAILABLE_ACTION);
    this.registerReceiver(myRssiChangeReceiver, rssiFilter);

    WifiManager wifiMan=(WifiManager)getActivity().getSystemService(Context.WIFI_SERVICE);
    wifiMan.startScan();
}


    @Override
public void onPause() {
    super.onPause();
    this.unregisterReceiver(myRssiChangeReceiver);

}
/**
 * Broadcast receiver to update 
 */
private BroadcastReceiver myRssiChangeReceiver
        = new BroadcastReceiver(){
    @Override
    public void onReceive(Context arg0, Intent arg1) {
        WifiManager wifiMan=(WifiManager)getActivity().getSystemService(Context.WIFI_SERVICE);
        wifiMan.startScan();
        int newRssi = wifiMan.getConnectionInfo().getRssi();
        Toast.makeText(getActivity(), ""+newRssi, Toast.LENGTH_SHORT).show();

}};

对不起，我来晚了，我只好发现我必须解决您的问题:P

Sorry I'm so late, I just had to find out I had to solve your problem :P

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