Question

我正在尝试使用谷歌地图从一个位置向另一个位置指定用户。我正在使用下面的代码，但我不知道为什么它不起作用。我无法弄清楚问题是否一切正常。

final double latitude = 37.894404;
final double longitude = -122.0660386;

locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
                Criteria criteria = new Criteria();
                criteria.setAccuracy(Criteria.ACCURACY_FINE);
                criteria.setAltitudeRequired(false);
                Location lastKnownLocation = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, true));

                if(lastKnownLocation != null){

                    double lat = lastKnownLocation.getLatitude();
                    double longi = lastKnownLocation.getLongitude();

                    Intent intent = new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("http://maps.google.com/maps?saddr="+lat+","+longi+"&daddr="+latitude+","+longitude));

                    startActivity(intent);

                }else{

                    Toast.makeText(contactus.this,"Coudn't get provider", Toast.LENGTH_SHORT).show();
                }           
            }

Answer 1

首先，您需要使用try / catch块包含对LocationManager的调用，并抓住您从调用中获得的任何异常。看看下面。这将进行调用并捕获异常..一旦你知道为什么它会返回NULL，就从那里开始。无论出于何种原因，您始终无法使用模拟器获取位置地理位置。此外，谷歌并不总是返回地理位置，所以在模拟器中我已经循环直到它回来了..不是一个好主意

    try{
                 Location lastKnownLocation = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, true));
                }
                catch(IOException e) {
                 Log.e("IOException", e.getMessage());

                 //Toaster on high-----------------//
                 Context context = getApplicationContext();
                 CharSequence text = "IOException:  " + e.getMessage();
                 int dur = Toast.LENGTH_LONG;
                    Toast.makeText(context, text, dur).show();

Answer 2

我实际上已经开始工作，这是我使用的代码，

final double latitude = 45.894404;
final double longitude = -112.0660386;

LocationManager lManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
Criteria crit = new Criteria();
String towers = lManager.getBestProvider(crit, false);
Location userCurrentLocation = lManager.getLastKnownLocation(towers);

if(userCurrentLocation != null){

     double lat = userCurrentLocation.getLatitude();
     double longi = userCurrentLocation.getLongitude();

     Intent intent = new Intent(android.content.Intent.ACTION_VIEW, Uri.parse("http://maps.google.com/maps?saddr="+lat+","+longi+"&daddr="+latitude+","+longitude));
     startActivity(intent);

}else{

    Toast.makeText(contactus.this, "Couldn't locate a provider to find your location", Toast.LENGTH_LONG).show();
}

不要忘记添加预设以查找清单的用户位置，将其包含在上面，

<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

Android：从Google地图获取路线

2 个答案: