java Gps android - 获取纬度和经度
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Gps android - getting Latitude and Longitude
提问by Sergio
Can you help me with that.. application started to crash when I added the geocoder to get the name of the city by using latitude and longitude..
你能帮我解决这个问题吗..当我添加地理编码器以使用纬度和经度获取城市名称时，应用程序开始崩溃..
double latitude, longitude;
private TextView lala;
LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
longitude = location.getLongitude();
latitude = location.getLatitude();
final LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
longitude = location.getLongitude();
latitude = location.getLatitude();
}
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
};
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, locationListener);
lala = (TextView) findViewById(R.id.textView1);
Geocoder myLocation = new Geocoder(getApplicationContext(), Locale.getDefault());
List<Address> myList = null;
try {
myList = myLocation.getFromLocation(latitude, longitude, 1);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
lala.setText((CharSequence) myList);
回答by Olegas
lm.getLastKnownLocationcan return null, and then tou try to getLongitude()you'll get NullPointerException
lm.getLastKnownLocation可以返回null，然后getLongitude()你尝试你会得到NullPointerException
Also lala.setText((CharSequence) myList);can do the same (throw Exception) cause' myList can be null here (if Geocoderis failed).
也lala.setText((CharSequence) myList);可以做同样的事情（抛出异常），因为'myList 在这里可以为空（如果Geocoder失败）。
EDITTo deal with exception in Geocoder consider the following checklist
编辑要处理地理编码器中的异常，请考虑以下清单
- Make sure your latitude and longitude are not null
- Make sure what -90 <= latitude <= 90 and -180 <= longitude <= 180
- Make sure you are having available network connection
- 确保您的纬度和经度不为空
- 确保 -90 <= 纬度 <= 90 和 -180 <= 经度 <= 180
- 确保您有可用的网络连接
EDIT2Improved code
EDIT2改进的代码
private TextView lala;
LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
Location location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
if(location != null) {
showMyAddress(location);
}
final LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
showMyAddress(location);
}
public void onProviderDisabled(String arg0) {
// TODO Auto-generated method stub
}
public void onProviderEnabled(String arg0) {
// TODO Auto-generated method stub
}
public void onStatusChanged(String arg0, int arg1, Bundle arg2) {
// TODO Auto-generated method stub
}
};
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10, locationListener);
lala = (TextView) findViewById(R.id.textView1);
// Also declare a private method
private void showMyAddress(Location location) {
double latitude = location.getLatitude();
double longitude = location.getLongitude();
Geocoder myLocation = new Geocoder(getApplicationContext(), Locale.getDefault());
List<Address> myList;
try {
myList = myLocation.getFromLocation(latitude, longitude, 1);
if(myList.size() == 1) {
lala.setText(myList.get(0).toString());
}
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
}
回答by user2760991
Criteria criteria = new Criteria();
LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
String provider = locationManager.getBestProvider(criteria, false);
Location location = locationManager.getLastKnownLocation(provider);
int la = (int) (location.getLatitude() * 1E6);
int lo = (int) (location.getLongitude() * 1E6);
