Wifi广播android内部的android意图

我正在学习android，并且被困在这里：

我正在编写的应用程序会定期在后台扫描Wifi信号。我正在使用android intent服务。问题是，应用程序永远不会执行BroadCastReceiver的onReceive（）方法

意图代码：

public class BackgroundIntent extends IntentService {

    // Default Constructor
    public BackgroundIntent() {
        super("BackgroundIntent");
        // TODO Auto-generated constructor stub
    }

    WifiManager mainWifi;
    BroadcastReceiver receiverWifi;

    private final Handler handler = new Handler();

    @TargetApi(Build.VERSION_CODES.GINGERBREAD)
    @Override
    protected void onHandleIntent(Intent intent) {
        // TODO Auto-generated method stub

        // Get mainWifi
        mainWifi = (WifiManager) getSystemService(Context.WIFI_SERVICE);
        if (mainWifi.isWifiEnabled() == false) {
            mainWifi.setWifiEnabled(true);
        }

        receiverWifi = new WifiReceiver();
        doInback();

    }

    // Basically a thread which calls itself after 5000milli sec
    public void doInback() {
        handler.postDelayed(new Runnable() {

            @Override
            public void run() {
                // TODO Auto-generated method stub
                mainWifi.startScan();
                Log.i("Inside ", "doInBack");

                // Call itself CODE GOES HERE :D
                doInback();
            }
        }, 5000);

    }

    public class WifiReceiver extends BroadcastReceiver {

        @TargetApi(Build.VERSION_CODES.GINGERBREAD)
        public void onReceive(Context c, Intent intent) {

            // CODE NEVER GOES HERE :(

            List<ScanResult> wifiList;
            wifiList = mainWifi.getScanResults();

            Log.i("Inside receiver", "yes");

        }
    }
}

调用android Intent服务的MainActivity代码

public class MainActivity extends Activity {
    TextView texty;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // Intent is called here
        Intent myIntent = new Intent(MainActivity.this, BackgroundIntent.class);
        startService(myIntent);

        texty = (TextView) findViewById(R.id.textView1);

    }

    public boolean onMenuItemSelected(int featureId, MenuItem item) {
        return super.onMenuItemSelected(featureId, item);
    }
}

知道可能是什么原因吗？这是实现背景wifi信号扫描的错误方法。当我在Main Activity中实现时，它运行正常，因此我猜测AndroidManifest.xml的编写正确。