android - BroadcastReceiver 后的运行时异常

Question

我正在尝试使用 BroadcastReceiver 获取互联网连接状态。

接收类是这样的:

public class ConnectivityReceiver extends BroadcastReceiver {

    WebView mWebView;



    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        Log.d(MSResearch.LOG_TAG, "Connectivity action: " + intent.getAction());
        if (action.equals(WifiManager.WIFI_STATE_CHANGED_ACTION)) {
            WifiManager wm = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
            Log.e(MSResearch.LOG_TAG, "Setting wifistate: " + wm.getWifiState());
        } else if (action.equals(ConnectivityManager.CONNECTIVITY_ACTION)) {
            NetworkInfo ni = intent.getParcelableExtra  (ConnectivityManager.EXTRA_NETWORK_INFO);
            Log.e(MSResearch.LOG_TAG, "Setting isConnected: " + ni.isConnected());
        }
    }
}

我在 onCreate() 函数中实例化了 Receive，并尝试在我的 Activity 类的 onResume() 中注册接收器，并在 onPause() 中注销它。

public onCreate(){
...
conReceiver = new ConnectivityReceiver();
itFilter = new IntentFilter(ConnectivityManager.CONNECTIVITY_ACTION);
itFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
...
}

@Override
public void onResume(){
    registerReceiver(conReceiver,itFilter);
}

@Override
public void onPause(){
   unregisterReceiver(conReceiver);
}

我在 onResume 调用后立即收到运行时异常。谁能告诉我我做错了什么？我什至尝试简单地在 list xml 文件中添加接收者标签，而不是在我的 Activity 中注册，但是我仍然遇到运行时异常。我在 2.2 和 2.3 模拟器上都试过了，但遇到了同样的问题。

Thread [<1> main] (Suspended (exception RuntimeException))  
    ActivityThread.performResumeActivity(IBinder, boolean) line: 3128   
    ActivityThread.handleResumeActivity(IBinder, boolean, boolean) line: 3143   
    ActivityThread.handleLaunchActivity(ActivityThread$ActivityRecord, Intent) line: 2684   
    ActivityThread.access$2300(ActivityThread, ActivityThread$ActivityRecord, Intent) line: 125 
    ActivityThread$H.handleMessage(Message) line: 2033  
    ActivityThread$H(Handler).dispatchMessage(Message) line: 99 
    Looper.loop() line: 123 
    ActivityThread.main(String[]) line: 4627    
    Method.invokeNative(Object, Object[], Class, Class[], Class, int, boolean) line: not available [native method]  
    Method.invoke(Object, Object...) line: 521  
    ZygoteInit$MethodAndArgsCaller.run() line: 868  
    ZygoteInit.main(String[]) line: 626 
    NativeStart.main(String[]) line: not available [native method]  

Answer 1

我在连接到服务时遇到了类似的问题，并且抛出了错误，因为我在绑定(bind)完成之前进行了远程调用。

我建议您在调用 registerReceiver 之前检查所有对象是否已初始化。