Question

我是Android的新手，需要帮助来解决这个问题。我有一个实现LocationListener的服务。当应用程序崩溃时，我收到以下错误。请解释我应该在我的代码中做出哪些更改。我已经参考了许多LocationListener和Services教程，但无法准确地弄清楚发生了什么。请逐步清除我的疑虑。我发布了我的代码和错误日志：

新错误日志：

 03-22 01:42:20.249: E/AndroidRuntime(6537): FATAL EXCEPTION: main
 03-22 01:42:20.249: E/AndroidRuntime(6537): java.lang.NullPointerException
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at com.example.broadcast.Ser.onLocationChanged(Ser.java:131)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at android.location.LocationManager$ListenerTransport._handleMessage(LocationManager.java:263)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at android.location.LocationManager$ListenerTransport.access$000(LocationManager.java:196)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at android.location.LocationManager$ListenerTransport$1.handleMessage(LocationManager.java:212)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at android.os.Handler.dispatchMessage(Handler.java:99)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at android.os.Looper.loop(Looper.java:137)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at android.app.ActivityThread.main(ActivityThread.java:4960)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at java.lang.reflect.Method.invokeNative(Native Method)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at java.lang.reflect.Method.invoke(Method.java:511)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
 03-22 01:42:20.249: E/AndroidRuntime(6537):    at dalvik.system.NativeStart.main(Native Method)

这是我的（新）服务代码：

public class Ser extends Service implements LocationListener{

   public Location getLocation(String provider) {
    if (locationManager.isProviderEnabled(provider)) {
        locationManager.requestLocationUpdates(provider,
                MIN_TIME_FOR_UPDATE, MIN_DISTANCE_FOR_UPDATE, this);
        if (locationManager != null) {
            location = locationManager.getLastKnownLocation(provider);


            double latitude = location.getLatitude();
            double longitude = location.getLongitude();
            String l1=String.valueOf(latitude);
            String l2=String.valueOf(longitude);


        }
    }

    return location;
}
 }
  public void onLocationChanged(Location location) {

    if(location!=null)
    {
    double latitude =location.getLatitude();
    double longitude = location.getLongitude();
    Log.i("msg","in locationchanged");

    }
   }

Answer 1

在

public void onLocationChanged(Location location) {

    double latitude =location.getLatitude();
    double longitude = location.getLongitude();
    Log.i("msg","in locationchanged");

}

检查location是否为空。

public void onLocationChanged(Location location) {
    if (location == null) return;

    double latitude =location.getLatitude();
    double longitude = location.getLongitude();
    Log.i("msg","in locationchanged");

}

Answer 2

getLastKnownLocation()可以返回null，因此您应该在调用location.getLatitude()和location.getLongitude()

之前对其进行检查

为什么服务使应用程序强行关闭？

2 个答案: