我有一个应用程序，可以获取用户当前位置，然后加载Google地图并在他们所在的区域绘制感兴趣的标记。它可以完美地作用于棉花糖以下的所有物体。我已经添加了运行时权限检查，并且在得到提示时进行了设置，在我点击接受后，我从手机设置中看到了应用程序详细信息中列出的权限。但是，我无法为自己的一生弄清楚为什么我找不到位置。
我使用的示例如此处https://developer.android.com/training/location/retrieve-current.html
我在清单中使用标签设置了所有权限。我什至有我的Fragment实现LocationListener。但是，永远不会调用onLocationChanged方法。我在Google API客户端的onConnected方法中调用它，如下所示。
@Override
public void onConnected(@Nullable Bundle bundle) {
try {
Log.d("MYAPPTAG","isConnected: " + mGoogleApiClient.isConnected());
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
myLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
} catch (SecurityException ex) {
myLocation = null;
}
}
之所以会调用onConnected方法，是因为我将日志发送到控制台。但是myLocation始终为null。每当我调用getLastLocation时，都会在控制台中收到一条消息，内容为：
No Location to return for getLastLocation()
GoogleSignatureVerifier: com.myappname.android signature not valid. Found: LONG KEY HERE
在棉花糖中我需要做些特别的事情吗？
我的OnLocationChanged方法
@Override
public void onLocationChanged(Location location) {
myLocation = location;
Log.d("MYAPPTAG", "LocatinChngListner, loc: " + location.getLatitude() + "," + location.getLongitude());
}
AndroidManifest.xml-权限部分（在节点上方）
<!--- App permissions -->
<permission android:name="com.myappname.android.permission.MAPS_RECEIVE" android:protectionLevel="signature"/>
<uses-permission android:name="com.myappname.android.permission.MAPS_RECEIVE"/>
<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_NETWORK_STATE"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES"/>
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.GET_ACCOUNTS"/>
<uses-permission android:name="android.permission.CALL_PHONE"/>
<uses-permission android:name="android.permission.KILL_BACKGROUND_PROCESSES" />
<uses-permission android:name="android.permission.WRITE_CONTACTS" />
<uses-permission android:name="android.permission.WAKE_LOCK" />
<uses-permission android:name="com.google.android.c2dm.permission.RECEIVE" />
<permission android:name="com.myappname.android.permission.C2D_MESSAGE" android:protectionLevel="signature" />
<uses-permission android:name="com.myappname.android.permission.C2D_MESSAGE"/>
onCreate方法片段
createLocationRequest();
if (mGoogleApiClient == null) {
mGoogleApiClient = new GoogleApiClient.Builder(getActivity())
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
}
createLocationRequest方法
private void createLocationRequest(){
mLocationRequest = LocationRequest.create();
mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequest.setInterval(5000);
mLocationRequest.setFastestInterval(1000);
}
onStart（）onStop（）方法
@Override
public void onStart() {
if (!mGoogleApiClient.isConnected()) mGoogleApiClient.connect();
super.onStart();
}
@Override
public void onStop() {
if (mGoogleApiClient.isConnected()) mGoogleApiClient.disconnect();
super.onStop();
}
我在Fragment onCreate方法之后在下面调用此代码
if (Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP_MR1 && (ContextCompat.checkSelfPermission(getActivity(), android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED || ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)) {
requestPermissions(new String[] { Manifest.permission.ACCESS_FINE_LOCATION, Manifest.permission.ACCESS_COARSE_LOCATION }, REQUEST_PERMISSION_USER_LOCATION);
} else {
googleMapsLocationPermissionContainer.setVisibility(View.GONE);
getUserLocationAndInitializeMap();
}
googleMapsLocationPermissionContainer只是在授予权限之前我在地图上覆盖的布局。
getUserLocationAndInitializeMap（）
try {
MapsInitializer.initialize(getActivity());
// Set reference for map object
if (map == null) {
mapFragment = (SupportMapFragment) getChildFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
// Here I set the map to invisible then after I plot all the markers I set it to visible again
mapFragment.getView().setVisibility(View.INVISIBLE);
}
} catch (Exception e) {
// Show the google maps alert dialog
showGoogleMapsErrorDialog();
}
最佳答案
我的处理方法如下：
@Override
public void onResume() {
super.onResume();
initGpsTracker();
}
public synchronized void initGpsTracker() {
if (mMap != null) {
try {
checkIfPermissionAllowedForLocation();
} catch (SecurityException secex) {
Toast.makeText(getActivity(), "not enabled in manifest", Toast.LENGTH_SHORT).show();
}
}
}
/**
* rule is the following. First we check if the permissions are there. If not, we check if we can enable or not.
* If the permissions are check if gps is enabled.
*/
private void checkIfPermissionAllowedForLocation() {
//if permissions are set then we go to else, check for gps
if (ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// Request missing location permission.
if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION)) {
askIfToRequestPermissions();
} else {
requestPermissions();
}
} else {
// Location permission has been granted, continue as usual.
if (!isGpsProviderEnabled()) {
askToEnableGPS();
} else {
mMap.setMyLocationEnabled(true);
}
}
}
private void askToEnableGPS() {
CustomFragmentDialog customFragmentDialog = CustomFragmentDialog.newInstance(getString(R.string.enable_gps_title),
getString(R.string.enable_gps_message),
getString(R.string.ok),
getString(R.string.cancel),
callback);
customFragmentDialog.show(getFragmentManager(), CUSTOM_TAG);
}
private void requestPermissions() {
ActivityCompat.requestPermissions(getActivity(),
new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
REQUEST_CODE_LOCATION);
}
private void enableGPS() {
if (enableLocationService != null) {
enableLocationService.askToEnableGps(locationCallback);
}
}
private GoogleAskToEnableLocationService.GpsCallback locationCallback = new GoogleAskToEnableLocationService.GpsCallback() {
@Override
public void onSuccess() {
initGpsTracker();
}
@Override
public void onResolutionRequired(Status status) {
try {
status.startResolutionForResult(getActivity(), CONNECTION_RESOLUTION_CODE);
} catch (IntentSender.SendIntentException setex) {
Toast.makeText(getActivity(), "Exception in sending intent:", Toast.LENGTH_SHORT).show();
}
}
@Override
public void onError() {
Toast.makeText(getActivity(), "Location services unavailable!", Toast.LENGTH_SHORT).show();
}
};
private void askIfToRequestPermissions() {
CustomFragmentDialog customFragmentDialog = CustomFragmentDialog.newInstance(getString(R.string.enable_gps_title),
getString(R.string.enable_permissions_message),
getString(R.string.ok),
getString(R.string.cancel),
callback_permissions);
customFragmentDialog.show(getFragmentManager(), CUSTOM_TAG);
}
private CustomFragmentDialog.Callback callback = new CustomFragmentDialog.Callback() {
@Override
public void onPositiveButtonClicked(Bundle bundle) {
enableGPS();
}
@Override
public void onNegativeButtonClicked(Bundle bundle) {
}
};
private CustomFragmentDialog.Callback callback_permissions = new CustomFragmentDialog.Callback() {
@Override
public void onPositiveButtonClicked(Bundle bundle) {
requestPermissions();
}
@Override
public void onNegativeButtonClicked(Bundle bundle) {
}
};
private boolean isGpsProviderEnabled() {
return googleUtils.isGpsProviderEnabled();
}
//inside it is a normal check if locationManager can access
//the gps provider
if (locationManager.getProvider(provider) == null) {
return false;
}
现在，为了获得请求权限，有一些回调：
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
switch (requestCode) {
case CONNECTION_RESOLUTION_CODE:
switch (resultCode) {
case Activity.RESULT_OK:
initGpsTracker();
break;
case Activity.RESULT_CANCELED:
Toast.makeText(getContext(), "Gps not enabled:", Toast.LENGTH_SHORT).show();
break;
default:
break;
}
break;
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
if (requestCode == REQUEST_CODE_LOCATION) {
if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
initGpsTracker();
} else {
Toast.makeText(getActivity(), "Manifest permission, not enabled", Toast.LENGTH_SHORT).show();
}
}
}
现在，最后是您处理位置请求的类，因此您不必进行设置：
public void askToEnableGps(final GpsCallback callback) {
if (locationClient == null) {
return;
}
mLocationRequestHighAccuracy = LocationRequest.create();
mLocationRequestHighAccuracy.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
mLocationRequestHighAccuracy.setInterval(30 * 1000);
mLocationRequestHighAccuracy.setFastestInterval(5 * 1000);
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder()
.addLocationRequest(mLocationRequestHighAccuracy);
builder.setAlwaysShow(true);
PendingResult<LocationSettingsResult> result =
LocationServices.SettingsApi.checkLocationSettings(locationClient, builder.build());
result.setResultCallback(getResultCallback(callback));
}
private ResultCallback<LocationSettingsResult> getResultCallback(final GpsCallback callback) {
return new ResultCallback<LocationSettingsResult>() {
@Override
public void onResult(LocationSettingsResult result) {
if (result != null) {
final Status status = result.getStatus();
if (callback != null) {
//final LocationSettingsStates statesResult = result.getLocationSettingsStates();
switch (status.getStatusCode()) {
case LocationSettingsStatusCodes.SUCCESS:
// All location settings are satisfied. The client can initialize location
// requests here.
callback.onSuccess();
break;
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
// Location settings are not satisfied. But could be fixed by showing the user
// a dialog.
callback.onResolutionRequired(status);
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
// Location settings are not satisfied. However, we have no way to fix the
// settings so we won't show the dialog.
callback.onError();
break;
}
}
}
}
};
}
public interface GpsCallback {
/**
* callback method for when the result it is a success.
*/
void onSuccess();
/**
* callback for when user interaction it is required.
*
* @param status the result from the service needed for the resolution.
*/
void onResolutionRequired(Status status);
/**
* Callback for when the change it is not possible.
*/
void onError();
}