Android onLocationChanged 和 MainActivity 类答案

【问题标题】：Android onLocationChanged and MainActivity classAndroid onLocationChanged 和 MainActivity 类
【发布时间】：2012-09-16 12:09:55
【问题描述】：

我有以下代码：

public class MyLocationListener implements LocationListener {


@Override
public void onLocationChanged(Location loc) {
    // called when the listener is notified with a location update from the GPS
    Log.d("Latitude", Double.toString(loc.getLatitude()));
    Log.d("Longitude", Double.toString(loc.getLongitude()));
}
@Override
public void onProviderDisabled(String provider) {
   // called when the GPS provider is turned off (user turning off the GPS on the phone)
}
@Override
public void onProviderEnabled(String provider) {
   // called when the GPS provider is turned on (user turning on the GPS on the phone)
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {

}

在我的 MainActivity 中

            LocationListener locationListener = new MyLocationListener();
        LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListener);

现在，我只想将设备的当前位置一次接收到 MainActivity 类（获取海拔和经度变量，以便稍后在应用程序中使用）。

A.一次后如何停止接收位置？函数 lm.removeUpdates(listener) 只能在 MainActivity 类中调用。

B.基本相同。如何连接 MyLocationListener 类和 MainActivity 类？

抱歉，我是 Android 和 Java 开发的新手。谢谢！

【问题讨论】：

标签： java android class gps locationlistener

【解决方案1】：

您可以使用以下示例代码：

public class LocationGetter {
    private final Context context;
    private Location location = null;
    private final Cordinate gotLocationLock = new Cordinate();
    private final LocationResult locationResult = new LocationResult() {
        @Override
        public void gotLocation(Location location) {
            synchronized (gotLocationLock) {
                LocationGetter.this.location = location;
                gotLocationLock.notifyAll();
                Looper.myLooper().quit();
            }
        }
    };

    public LocationGetter(Context context) {
        if (context == null)
            throw new IllegalArgumentException("context == null");

        this.context = context;
    }

    public  void getLocation(int maxWaitingTime, int updateTimeout) {
        try {
            final int updateTimeoutPar = updateTimeout;
            synchronized (gotLocationLock) {
                new Thread() {
                    public void run() {
                        Looper.prepare();
                        LocationResolver locationResolver = new LocationResolver();
                        locationResolver.prepare();
                        locationResolver.getLocation(context, locationResult, updateTimeoutPar);
                        Looper.loop();
                    }
                }.start();

                gotLocationLock.wait(maxWaitingTime);
            }
        } catch (InterruptedException e1) {
            e1.printStackTrace();
        }
        gteAddress ();
    }


public double getLatitude() {
    return location.getLatitude();
}

public double getLongitude() {
    return location.getLongitude();
}

在你的活动中使用：

_locationGetter=new LocationGetter(context);

_locationGetter.getLocation(200000000, 10000000);

_locationGetter.getLongitude();

_locationGetter.getLatitude();

【讨论】：

谢谢，我没想到！但是我如何在课堂上使用它？我怎么知道它何时获得价值？
在你的活动中使用线程来获取位置&当线程完成时调用 getLongitude() && getLatitude() 方法它会通知你。

【解决方案2】：

您也可以在获取坐标后使用 LocationManager.removeUpdates（并可能检查坐标是否足以满足您的需要）：

        @Override
    public void onLocationChanged(Location loc) {
        // called when the listener is notified with a location update from the GPS
        Log.d("Latitude", Double.toString(loc.getLatitude()));
        Log.d("Longitude", Double.toString(loc.getLongitude()));
        lm.removeUpdates(this);
    }

【讨论】：

只需将 MyLocationManager 设为 MainActivity 的内部类。