相关疑难解决方法(0)

有没有办法访问GPS一次,而不是有一个不断检查位置更新的looper？

在我的场景中,我感兴趣的是找到当前的坐标而不是与GPS卫星的连续连接.有没有人有任何想法如何做到这一点？提前致谢.

我想找到一个Android项目的当前位置.加载应用程序时,我的当前位置始终为null.我已经在清单等中设置了权限.当我找到当前位置时,我打算使用坐标来查找到地图上其他位置的距离.我的代码片段如下.为什么我总是得到一个空值？

locMan = (LocationManager) getSystemService(Context.LOCATION_SERVICE);          
Criteria crit = new Criteria();     
towers = locMan.getBestProvider(crit, false);
location = locMan.getLastKnownLocation(towers);    

if (location != null) {                 
    System.out.println("Location is not null!");
    lat = (int) (location.getLatitude() *1E6);
    longi = (int) (location.getLongitude() * 1E6);
    GeoPoint ourLocation = new GeoPoint(lati, longi);
    OverlayItem overlayItem = new OverlayItem(ourLocation, "1st String",
                                                            "2nd String");
    CustomPinpoint custom = new CustomPinpoint(d, MainMap.this);
    custom.insertPinpoint(overlayItem);
    overlayList.add(custom);
    overlayList.clear();
} else {
   System.out.println("Location is null! " + towers);
   Toast.makeText(MainMap.this, "Couldn't get provider",Toast.LENGTH_SHORT)
                                                                    .show();
}

我刚刚开始工作,但是当我关闭我的Wifi以确定我是否可以使用我的GPS获得更准确的位置时,它现在给我带来了一个NullPointer错误,我看不出原因.

首先调用下面的代码;

 public void onConnected(Bundle dataBundle) {
        connected = true;
        //Request an update from the location client to get current Location details
        mLocationClient.requestLocationUpdates(mLocationRequest,this);
        Toast.makeText(this, "Connected", Toast.LENGTH_SHORT).show();
    }

然后需要调用此方法

public void onLocationChanged(android.location.Location location) {
        // Report to the UI that the location was updated
        String msg = "Updated Location: " +
                Double.toString(location.getLatitude()) + "," +
                Double.toString(location.getLongitude());
        if(tmp != location.getLatitude())
        {
            Toast.makeText(this, msg, Toast.LENGTH_SHORT).show();
        }
        tmp = location.getLatitude();
    }

你可以看到我在那里有两个吐司,他们用实际的GPS坐标回来了,但是当我调用下面的代码时,它会在新的位置线上崩溃 getLastKnownLocation

public String getLocation()
    {
        // Get the location manager …

我想通过最好的提供商从gps/netwrok获取位置,但总是返回相同的位置,我也可以看到谷歌地图上有一个标志到我的正确位置.请有人能告诉我我做错了什么吗？

我的活动是:

 public class MainMenu2 extends Activity implements LocationListener, OnClickListener

在我的onCreate我有:

 if(isGooglePlay()){
        setContentView(R.layout.menu_2);
        setUpMapIfNeeded();
    }

isGooglePlay方法:

 private boolean isGooglePlay() { // looks if googlemaps is available

    int status = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
    if(status == ConnectionResult.SUCCESS){
        return true;
    }
    else{
        ((Dialog) GooglePlayServicesUtil.getErrorDialog(status, this, 10)).show();
        //Toast.makeText(this, "Google Play is not available", Toast.LENGTH_SHORT).show();
        return(false);
    }

}//isGooglePlay

setUpMapIfNeeded方法:

   private void setUpMapIfNeeded() {
// Do a null check to confirm that we have not already instantiated the map.
if (mMap == null) {
    mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.menu_map)) …

我有一个代码应该返回用户位置,但经度不断返回null,因此我的应用程序不断崩溃.我该如何防止这种情况？

//get the user longitude and latitude
LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE); 
Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
double longitude = location.getLongitude();
double latitude = location.getLatitude();

Geocoder geocoder;  //return meaningful data from user location
List<Address> addresses;
geocoder = new Geocoder(this, Locale.getDefault());
addresses = geocoder.getFromLocation(latitude, longitude, 1);
address = addresses.get(0).getAddressLine(0);
city = addresses.get(0).getLocality();