我正在尝试获取我的位置。但我所拥有的一切都是零。请看代码:
public class ListBranchesActivity extends Activity {
private double lat, lon;
private LocationManager lm;
private Location location;
private final LocationListener locationListener = new LocationListener() {
public void onLocationChanged(Location location) {
lon = location.getLongitude();
lat = location.getLatitude();
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
// TODO Auto-generated method stub
}
@Override
public void onProviderEnabled(String provider) {
// TODO Auto-generated method stub
}
@Override
public void onProviderDisabled(String provider) {
// TODO Auto-generated method stub
}
};
然后在onCreate()中的某个地方:
lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 2000, 10,
locationListener);
location = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
以下代码返回 NullPointerException:
Log.w("es09", "coordinates are " + lon + " " + lat +" " +location.getLatitude()+" "+ location.getLongitude());
该代码返回“坐标为 0.0 0.0”
Log.w("es09", "coordinates are " + lon + " " + lat);
我的 list 权限:
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.READ_INTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_INTERNAL_STORAGE" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.CALL_PHONE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_GPS"/>
<uses-permission android:name="android.permission.ACCESS_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_ASSISTED_GPS"/>
出了什么问题？
最佳答案
问题是您假设您总是能找回位置，但事实并非如此。无法保证位置会返回给您，因此您必须检查是否为空。
使用
lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
不能保证最后一个位置存在，每当您获得一个位置时，您始终应该首先检查以确保它不为空!
关于java - Android 中的位置为空，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/29516812/