Wifi连接状态监听器

Question

我正在尝试实现一个简单的BroadcastReceiver，以便我的活动知道何时连接/断开了WIFI。

我当前的代码如下：

@Override
protected void onResume() {
    super.onResume();

    broadcastReceiver = new BroadcastReceiver() {

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

            ConnectivityManager connectionManager = (ConnectivityManager) SicPlayerApp.getInstance().getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);

            boolean isWifiConnected = connectionManager.getActiveNetworkInfo() != null && 
                    connectionManager.getActiveNetworkInfo().getType() == ConnectivityManager.TYPE_WIFI &&
                    connectionManager.getActiveNetworkInfo().getState() == NetworkInfo.State.CONNECTED;

            Log.i("testnetwork", "isConnectedOrConnecting: " + isWifiConnected);
        }
    };

    IntentFilter intentFilter = new IntentFilter();
    intentFilter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
    registerReceiver(broadcastReceiver, intentFilter);
}

@Override
protected void onPause() {
    super.onPause();

    unregisterReceiver(broadcastReceiver);
}

并在我的AndroidManifest.xml中：

<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>

我永远无法在该日志行上获得 true 。

奇怪的是，如果我这样做：

@Override
public void onReceive(Context context, Intent intent) {
            new CountDownTimer(3000, 3000){

                @Override
                public void onTick(long millisUntilFinished) {

                }

                @Override
                public void onFinish() {
                    ConnectivityManager connectionManager = (ConnectivityManager) SicPlayerApp.getInstance().getApplicationContext().getSystemService(Context.CONNECTIVITY_SERVICE);

                    boolean isWifiConnected = connectionManager.getActiveNetworkInfo() != null &&
                            connectionManager.getActiveNetworkInfo().getType() == ConnectivityManager.TYPE_WIFI &&
                            connectionManager.getActiveNetworkInfo().getState() == NetworkInfo.State.CONNECTED;

                    Log.i("testnetwork", "isConnectedOrConnecting: " + isWifiConnected);
                }
            }.start();
        }

它运作完美！