在某些设备上未调用onLocationChanged [英] onLocationChanged not called on some devices

问题描述

这个问题已经问了很多遍了，但是我找不到一个始终有效的解决方案.

This is a question which has been asked numerous times but I could not find a solution that always works.

我正在使用Fused位置提供程序开发应用程序. 在onConnected()方法中，我请求位置更新，并且一旦生成位置定位并调用onLocationChanged()，就会启动应用程序逻辑. (请参阅下面的代码).

I am developing an application using the Fused location provider. In the onConnected() method, I am requesting for location updates and the application logic will be initiated once a location fix is generated and onLocationChanged() is called. (Please refer to my code below).

问题 onLocationChanged()方法.我使用Samsung Tab 2和Samsung Galaxy Grand进行测试.此代码在Tab 2上可以正常工作，但在Grand上不起作用.通过不起作用，我的意思是locationClient已连接，但从未调用onLocationChanged().

Problem onLocationChanged() method is never called on some devices. I use a Samsung Tab 2 and a Samsung Galaxy Grand for testing. This code works perfectly fine on the Tab 2 but does not work on Grand. By does not work, I mean that locationClient gets connected but onLocationChanged() is never called.

之前，我使用位置管理器来获取位置，在该实现中，发生了相同的问题.因此，我尝试实现融合的位置提供程序，但仍然遇到相同的问题.

Earlier, I used the location manager for getting location and in that implementation, the same problem occurred. So, I tried implementing the fused location provider but I still get the same problem.

有人可以帮我解决这个问题吗?这里有我想念的东西吗?

Can anyone help me out with this issue? Is there something I am missing here?

public class MainActivity extends Activity implements GooglePlayServicesClient.ConnectionCallbacks, OnConnectionFailedListener, LocationListener {

LocationClient locationclient;
LocationRequest lr;
Location loc1;
static String address;

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

    locationclient = new LocationClient(this,this,this);
    locationclient.connect();        

}

@Override
public void onConnected(Bundle arg0) {
    // TODO Auto-generated method stub

    lr=LocationRequest.create();
    lr.setInterval(100);
    locationclient.requestLocationUpdates(lr, this);
    Log.d("LocationClient","On Connected");
}

@Override
public void onDisconnected() {
    // TODO Auto-generated method stub
    locationclient.disconnect();

}

@Override
public void onConnectionFailed(ConnectionResult arg0) {
    // TODO Auto-generated method stub

}

@Override
public void onLocationChanged(Location loc) {
    // TODO Auto-generated method stub      

    // Application Logic        

    Log.d("LocationClient","Last Known Location LC:" + loc.getLatitude() + "," + loc.getLongitude());
}
}

推荐答案

我在Galaxy Nexus上观察到了相同的行为，并且发现了导致onLocationChanged()不被调用的两件事.有

I observed same behavior on Galaxy Nexus and recognized two things causing onLocationChanged() to not being called. There are

1. 在系统设置"中未启用相应的位置源.对于PRIORITY_HIGH_ACCURACY，必须启用 GPS卫星，对于PRIORITY_BALANCED_POWER_ACCURACY Wi-Fi&移动网络位置必须启用.

1. Corresponding location source is not enabled in System Settings. For PRIORITY_HIGH_ACCURACY the GPS satellites must be enabled, for PRIORITY_BALANCED_POWER_ACCURACY Wi-Fi & mobile network location must be enabled.

即使对于已启用的位置源，也没有可用的有效位置信息.例如，启用了PRIORITY_HIGH_ACCURACY源，但没有(或效果不佳)GPS接收(例如，设备在建筑物内).或PRIORITY_BALANCED_POWER_ACCURACY源已启用，但Wi-Fi和移动数据均已关闭.在这种情况下，无法检测到位置并且不会调用onLocationChanged().

Even for the enabled location sources there can be no valid location information available. For instance, PRIORITY_HIGH_ACCURACY source is enabled, but there is no (or not good) GPS reception (e.g. device is inside a building). Or PRIORITY_BALANCED_POWER_ACCURACY source is enabled, but both Wi-Fi and mobile data are switched off. In those cases location cannot be detected and onLocationChanged() will not be called.

要解决第1个问题，即使在连接到Google Services API之前，我也必须检查是否已启用必需的位置信息源，如果它们已关闭，则我通知用户要求他/她允许位置信息访问.

To fix #1 I had to check whether required location sources are enabled even before connecting to Google Services API and if they are switched off, then I notified a user asked him/her to allow location access.

为解决#2，我决定使用LocationRequest.setExpirationDuration().我将超时设置为大约10秒，并且在调用requestLocationUpdates()后立即发布了延迟了同样10秒的回调.如果在requestLocationUpdates()之前调用了延迟回调，则意味着由于原因2无法检测到位置.我进行了三次重试，然后向用户显示错误消息.

To solve #2 I decided to use LocationRequest.setExpirationDuration(). I set timeout at about 10 seconds, and immediately after calling requestLocationUpdates() I post a callback delayed by same 10 seconds. If delayed callback is called before requestLocationUpdates(), this means location cannot be detected due to reason #2. I do three retries and then show user an error message.

Android文档在这个地方不是很好，这就是为什么我希望这会有所帮助.

Android documentation is not great at this place, that's why I hope this helps.

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