Question

我正在开发一个位置感应应用程序，但我已陷入停滞状态。我想要做的是能够向Android设备询问单个GPS位置并将其返回。

到目前为止，这就是我所拥有的。应该定期更新位置的服务：

import android.app.Service;
import android.content.Context;
import android.content.Intent
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.widget.Toast;

import java.util.Date;
import java.util.Timer;
import java.util.TimerTask;
public class KeepTime extends Service implements LocationListener {
float minAccuracyMeters = 20.0f;
LocationManager locationManager;
int index = 0;

int maxAmountOfTries = 5;
Timer timer;

boolean currentlyListening = false;
@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    System.out.println("Service started..");
    Toast.makeText(this, "Service started", Toast.LENGTH_SHORT).show();
    locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
    if(!isLocationEnabled()){
        System.out.println("Location service is not active. Stopping self.");
        Toast.makeText(this, "Location service is not active. Stopping self.", Toast.LENGTH_SHORT).show();
        this.stopSelf();
        return 0;
    }

    timer = new Timer();
    timer.schedule(new TimerTask() {

        @Override
        public void run() {

            if (currentlyListening) {

            } else {
                setListener();
            }
        }
    }, 0, 1000 * 60 * 10);

    return Service.START_NOT_STICKY;
}

@Override
public void onDestroy() {
    super.onDestroy();

    mll.removeListener();
    mll.cancelTimer();
    Toast.makeText(this, "Service Destroyed", Toast.LENGTH_SHORT).show();
    System.out.println("Service destroyed..");
}
@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}

private boolean isLocationEnabled() {

    return locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER) ||
            locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
}

private void setListener()
{
    System.out.println("Set listener called..");
    try {
        System.out.println("About to set listeners");
        locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, this);
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, this);
        System.out.println("Location listeners set..");
        currentlyListening = true;
    }catch(SecurityException e){
        System.out.println("Security exception. "+e);
    }
}

public void removeListener() {
    try {
        locationManager.removeUpdates(this);
        System.out.println("Removed updates..");
        currentlyListening = false;
    } catch (SecurityException se) {
        System.out.println("Security exception: " + se);
    }
}

@Override
public void onLocationChanged(Location location) {
    System.out.println("Location changed..");
    double longitudeNetwork = location.getLongitude();
    double latitudeNetwork = location.getLatitude();
    double accuracy = location.getAccuracy();

    if(accuracy < minAccuracyMeters || index > maxAmountOfTries) {
        System.out.println("Accuracy is less than " + minAccuracyMeters + " Recording..");
System.out.println(longitudeNetwork+ " "+latitudeNetwork+ " "+accuracy);

        removeListener();
    }
    else{
        System.out.println("Accuracy was not good enough. Still recorded location.");

    }
    index++;
}

@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
    System.out.println("Status changed");
}

@Override
public void onProviderEnabled(String provider) {
    System.out.println("Provider enabled.");
}

@Override
public void onProviderDisabled(String provider) {
    System.out.println("Provider disabled.");
}
}

每隔10分钟，我希望在达到一定精度或经过一定时间后打印出位置。但它抛出异常。这是一个例外：

FATAL EXCEPTION: Timer-0
java.lang.RuntimeException: Can't create handler inside thread that has not called Looper.prepare()

我试过调试准备，但这只会造成更大的破坏。任何想法如何实现我的目标？

Answer 1

TimerTask适用于不同的线程，因此您的问题可能会引用this

并检查this项目，似乎它完全提到了你的整个想法

修改

不是浪费时间，而是为他展示关键材料。对于第一个链接，我已经告诉它是关键。

TimerTask适用于不同的线程

您可以在链接中执行与已接受答案相同的操作。因此，您必须在主线程中运行代码作用域，因为服务也适用于主线程。

或者您可以使用handler.postDelayed而不是TimerTask。

我并没有直接将你转发给浪费的链接，因为我会分析你的整个代码。它指的是github上commonsguy的完美项目。所以你可以通过查看commonsguy项目来消除你的错误。

Answer 2

locationmanager.requestlocationupdates有一个间隔参数，以便何时再次获取位置。尝试按ctrl并将鼠标悬停在requestlocationupdate语法上。

在Android应用中获取定期GPS定位

2 个答案: