如何在地图初始化之前询问是否启用了位置？ 如果我尝试在MapsActivity上请求权限，它会退出应用程序，因为它未启用。 我已经尝试将其添加到将用户定向到Map的活动中。但它仍然只是关闭活动，除非该位置已启用。
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync((OnMapReadyCallback) this);
setUpMap();
}
private void buildAlertMessageNoGps() {
final AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setMessage("Your GPS seems to be disabled, do you want to enable it?")
.setCancelable(false)
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
public void onClick(@SuppressWarnings("unused") final DialogInterface dialog, @SuppressWarnings("unused") final int id) {
startActivity(new Intent(android.provider.Settings.ACTION_LOCATION_SOURCE_SETTINGS));
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
public void onClick(final DialogInterface dialog, @SuppressWarnings("unused") final int id) {
dialog.cancel();
}
});
final AlertDialog alert = builder.create();
alert.show();
}
@Override
protected void onResume() {
super.onResume();
setUpMap();
}
private void setUpMap() {
final LocationManager manager = (LocationManager) getSystemService( Context.LOCATION_SERVICE );
if ( !manager.isProviderEnabled( LocationManager.GPS_PROVIDER ) ) {
buildAlertMessageNoGps();
}
new Thread(new Runnable() {
public void run() {
try {
retrieveAndAddCities();
} catch (IOException e) {
Log.e(LOG_TAG, "Cannot retrive cities", e);
return;
}
}
}).start();
}
protected void retrieveAndAddCities() throws IOException {
HttpURLConnection conn = null;
final StringBuilder json = new StringBuilder();
try {
// Connect to the web service
URL url = new URL(SERVICE_URL);
conn = (HttpURLConnection) url.openConnection();
InputStreamReader in = new InputStreamReader(conn.getInputStream());
// Read the JSON data into the StringBuilder
int read;
char[] buff = new char[1024];
while ((read = in.read(buff)) != -1) {
json.append(buff, 0, read);
}
} catch (IOException e) {
Log.e(LOG_TAG, "Error connecting to service", e);
throw new IOException("Error connecting to service", e);
} finally {
if (conn != null) {
conn.disconnect();
}
}
runOnUiThread(new Runnable() {
public void run() {
try {
createMarkersFromJson(json.toString());
} catch (JSONException e) {
Log.e(LOG_TAG, "Error processing JSON", e);
}
}
});
}
Marker mClosestMarker;
float mindist;
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
//Location Permission already granted
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
} else {
}
} else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
@Override
public void onPause() {
super.onPause();
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}
}
void createMarkersFromJson(String json) throws JSONException {
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
mGoogleApiClient);
JSONArray jsonArray = new JSONArray(json);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObj = jsonArray.getJSONObject(i);
double lat = jsonObj.getJSONArray("latlng").getDouble(0);
double lon = jsonObj.getJSONArray("latlng").getDouble(1);
final String address = jsonObj.getString("address");
Marker currentMarker = mMap.addMarker(new MarkerOptions()
.title(jsonObj.getString("name"))
.snippet(Integer.toString(jsonObj.getInt("population"))).draggable(true)
.position(new LatLng(jsonObj.getJSONArray("latlng").getDouble(0), jsonObj.getJSONArray("latlng").getDouble(1)))
.icon(BitmapDescriptorFactory
.defaultMarker(BitmapDescriptorFactory.HUE_AZURE)));
mMap.setOnMarkerClickListener(new GoogleMap.OnMarkerClickListener() {
@Override
public boolean onMarkerClick(final Marker marker) {
new AlertDialog.Builder(MapsActivity.this)
.setTitle("Call Local Distributor " + marker.getTitle())
.setMessage("Would you like to dial now ? ")
.setPositiveButton("Yes", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
Intent intent = new Intent(Intent.ACTION_DIAL);
intent.setData(Uri.parse("tel:" + marker.getSnippet()));
startActivity(intent);
}
})
.setNegativeButton("No", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
}
})
.create()
.show();
return true;
}
});
float[] distance = new float[1];
Location.distanceBetween(mLastLocation.getLatitude(), mLastLocation.getLongitude(), lat, lon, distance);
if (i == 0) {
mindist = distance[0];
} else if (mindist > distance[0]) {
mindist = distance[0];
mClosestMarker = currentMarker;
Toast.makeText(getApplicationContext(),
mClosestMarker.getTitle(), Toast.LENGTH_LONG)
.show();
}
}
}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API)
.build();
mGoogleApiClient.connect();
}
@Override
public void onConnected(Bundle bundle) {
mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(100);
mLocationRequest.setFastestInterval(100);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
if (connectionResult.hasResolution()) {
try {
connectionResult.startResolutionForResult(this, CONNECTION_FAILURE_RESOLUTION_REQUEST);
} catch (IntentSender.SendIntentException e) {
e.printStackTrace();
}
} else {
Log.i(TAG, "Location services connection failed with code " + connectionResult.getErrorCode());
}
}
@Override
public void onLocationChanged(Location location) {
mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
currentLatitude = location.getLatitude();
currentLongitude = location.getLongitude();
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
mCurrLocationMarker = mMap.addMarker(markerOptions);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, 5));
}
}
我厌倦了在OnCreate中使用此代码段，但如果位置被禁用，则应用程序无法启动。
LocationManager lm = (LocationManager) getSystemService(LOCATION_SERVICE);
if(!lm.isProviderEnabled(LocationManager.GPS_PROVIDER) ||
!lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER)) {
// Build the alert dialog
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Location Services Not Active");
builder.setMessage("Please enable Location Services and GPS");
builder.setPositiveButton("OK", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialogInterface, int i) {
// Show location settings when the user acknowledges the alert dialog
Intent intent = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(intent);
}
});
Dialog alertDialog = builder.create();
alertDialog.setCanceledOnTouchOutside(false);
alertDialog.show();
}
答案 0 :(得分：1)
下面是我用于我的应用程序的代码片段它工作正常，检查它是否也适合你
int off = 0;
try {
off = Settings.Secure.getInt(getContentResolver(), Settings.Secure.LOCATION_MODE);
} catch (Settings.SettingNotFoundException e) {
e.printStackTrace();
}
if (off == 0) {
AlertDialog.Builder builder = new AlertDialog.Builder(this);
builder.setTitle("GPS is not enbled.");
builder.setMessage("To Get Your Current Location You have To Enable Gps \n Are Sure Want to go to seeting to Enable GPS?");
builder.setPositiveButton("YES", new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
// Do nothing but close the dialog
Intent onGPS = new Intent(Settings.ACTION_LOCATION_SOURCE_SETTINGS);
startActivity(onGPS);
// Toast.makeText(MapsActivity.this, c_lat +","+c_long, Toast.LENGTH_SHORT).show();
}
});
builder.setNegativeButton("NO", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// Do nothing
dialog.dismiss();
}
});
AlertDialog alert = builder.create();
alert.show();