小编jav*_*ser的帖子

我有一个服务,以一定的间隔轮询服务器.我使用AlarmManager和BroadcastReceiver来启动服务.我的问题是,经过一段时间后,即使Wifi仍然启用,但由于某种原因,我的应用程序无法联系服务器.我收到"无法访问的网络"错误.

请注意,我已经获得了部分唤醒锁和wifilock.

这是我的BroadcastReceiver代码.

public class ServiceAlarmBroadcastReceiver extends BroadcastReceiver {
    public void onReceive(Context context, Intent intent) {
        WakeLock wakeLock = null;
        WifiLock wifiLock = null;
        try {
            PowerManager pm = (PowerManager) context
                    .getSystemService(Context.POWER_SERVICE);

            // acquire a WakeLock to keep the CPU running
            wakeLock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK,
                    "MyWakeLock");
            if(!wakeLock.isHeld()){
                wakeLock.acquire();
            }

            Log.i("ServiceAlarmBroadcastReceiver", "WakeLock acquired!");


            WifiManager wm = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
            wifiLock = wm.createWifiLock(WifiManager.WIFI_MODE_FULL , "MyWifiLock");
            if(!wifiLock.isHeld()){
                wifiLock.acquire();
            }

            Log.i("ServiceAlarmBroadcastReceiver", "WifiLock acquired!");
            context.startService(new Intent(context, ThePollerService.class));
        } finally {
            // release the WakeLock to allow CPU …

我正在尝试在活动之外查询联系人内容提供商.但是,managedQuery是一种Activity的方法.是否有任何其他类/方法可以使用而不是managedQuery？

这是我的代码:

class MyActivity extends Activity {

  private Cursor getContacts() {
 Uri uri = ContactsContract.Contacts.CONTENT_URI;
 String[] projection = new String[] { ContactsContract.Contacts._ID,
   ContactsContract.Contacts.DISPLAY_NAME,
   ContactsContract.Contacts.HAS_PHONE_NUMBER };
 String where = null;
 String[] whereArgs = null;
 String sortOrder = ContactsContract.Contacts.DISPLAY_NAME
   + " COLLATE LOCALIZED ASC";

 return context.managedQuery(uri, projection, where, whereArgs, sortOrder);
  } 
}