Android对LocationManager的检查权限 [英] Android check permission for LocationManager
问题描述
当我在活动布局中单击一个按钮时，我试图显示GPS坐标.以下是单击按钮时调用的方法:
I'm trying to get the GPS coordinates to display when I click a button in my activity layout. The following is the method that gets called when I click the button:
public void getLocation(View view) {
TextView tv = (TextView) findViewById(R.id.gps_coord_view);
LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE);
Location loc = lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
tv.setText("Latitude: " + loc.getLatitude() + "\nLongitude: " + loc.getLongitude());
}
我收到一条错误消息
呼叫需要许可，用户可能会拒绝它.代码应明确检查权限是否可用.
Call requires permission which may be rejected by user. Code should explicitly check to see if permission is available.
我已经在AndroidManifest中授予了这些权限.当我在调用lm.getLastKnownLocation之前添加以下内容时，该错误会得到解决，并且应用程序会编译:
I have already granted these permissions in my AndroidManifest. The error is taken care of and the app compiles when I add the following before calling lm.getLastKnownLocation:
if (checkSelfPermission(Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED
&& checkSelfPermission(Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
但是，当我按下调用getLocation的按钮时，该应用程序崩溃了.到底是怎么回事?有没有更好/更简单的方法来获取设备的GPS坐标?
However, the app crashes when I press the button that calls getLocation when it's clicked. What is going on? Is there better/simpler way to grab the GPS coordinates of the device?
推荐答案
对于Android API级别(23)，我们需要检查权限. https://developer.android.com/training/permissions/requesting.html
With Android API level (23), we are required to check for permissions. https://developer.android.com/training/permissions/requesting.html
我遇到了同样的问题，但是以下方法对我有用，并且我能够成功检索位置数据:
I had your same problem, but the following worked for me and I am able to retrieve Location data successfully:
(1)确保清单中列出了您的权限:
(1) Ensure you have your permissions listed in the Manifest:
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
(2)确保您请求用户权限:
(2) Ensure you request permissions from the user:
if ( ContextCompat.checkSelfPermission( this, android.Manifest.permission.ACCESS_COARSE_LOCATION ) != PackageManager.PERMISSION_GRANTED ) {
ActivityCompat.requestPermissions( this, new String[] { android.Manifest.permission.ACCESS_COARSE_LOCATION },
LocationService.MY_PERMISSION_ACCESS_COURSE_LOCATION );
}
(3)确保使用ContextCompat，因为它与较旧的API级别兼容.
(3) Ensure you use ContextCompat as this has compatibility with older API levels.
(4)在您的位置服务或用于初始化LocationManager并获取最后一个已知位置的类中，我们需要检查权限:
(4) In your location service, or class that initializes your LocationManager and gets the last known location, we need to check the permissions:
if ( Build.VERSION.SDK_INT >= 23 &&
ContextCompat.checkSelfPermission( context, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED &&
ContextCompat.checkSelfPermission( context, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return ;
}
(5)仅当我在initLocationService方法的顶部包含@TargetApi(23)后，此方法才对我有用.
(5) This approach only worked for me after I included @TargetApi(23) at the top of my initLocationService method.
(6)我还将其添加到我的gradle版本中:
(6) I also added this to my gradle build:
compile 'com.android.support:support-v4:23.0.1'
这是我的LocationService供参考:
Here is my LocationService for reference:
public class LocationService implements LocationListener {
//The minimum distance to change updates in meters
private static final long MIN_DISTANCE_CHANGE_FOR_UPDATES = 0; // 10 meters
//The minimum time between updates in milliseconds
private static final long MIN_TIME_BW_UPDATES = 0;//1000 * 60 * 1; // 1 minute
private final static boolean forceNetwork = false;
private static LocationService instance = null;
private LocationManager locationManager;
public Location location;
public double longitude;
public double latitude;
/**
* Singleton implementation
* @return
*/
public static LocationService getLocationManager(Context context) {
if (instance == null) {
instance = new LocationService(context);
}
return instance;
}
/**
* Local constructor
*/
private LocationService( Context context ) {
initLocationService(context);
LogService.log("LocationService created");
}
/**
* Sets up location service after permissions is granted
*/
@TargetApi(23)
private void initLocationService(Context context) {
if ( Build.VERSION.SDK_INT >= 23 &&
ContextCompat.checkSelfPermission( context, android.Manifest.permission.ACCESS_FINE_LOCATION ) != PackageManager.PERMISSION_GRANTED &&
ContextCompat.checkSelfPermission( context, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return ;
}
try {
this.longitude = 0.0;
this.latitude = 0.0;
this.locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
// Get GPS and network status
this.isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
this.isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
if (forceNetwork) isGPSEnabled = false;
if (!isNetworkEnabled && !isGPSEnabled) {
// cannot get location
this.locationServiceAvailable = false;
}
//else
{
this.locationServiceAvailable = true;
if (isNetworkEnabled) {
locationManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
updateCoordinates();
}
}//end if
if (isGPSEnabled) {
locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER,
MIN_TIME_BW_UPDATES,
MIN_DISTANCE_CHANGE_FOR_UPDATES, this);
if (locationManager != null) {
location = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
updateCoordinates();
}
}
}
} catch (Exception ex) {
LogService.log( "Error creating location service: " + ex.getMessage() );
}
}
@Override
public void onLocationChanged(Location location) {
// do stuff here with location object
}
}
到目前为止，我仅使用Android Lollipop设备进行了测试. 希望这对您有用.
I tested with an Android Lollipop device so far only. Hope this works for you.
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