Question

我在尝试加载地图活动时，会出现“我的位置”按钮。这是我的代码，并且我的活动放大到我当前位置的按钮没有出现。我需要在代码中进行哪些更改才能使其正常工作？

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private static final String FIREBASE_URL="https://********.firebaseio.com/";
private Firebase firebaseRef;
private LocationManager locationManager;
private GoogleMap mMap;
SupportMapFragment mapFrag;
boolean bPermissionGranted;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps2);
    Firebase.setAndroidContext(this);
    firebaseRef = new Firebase(FIREBASE_URL);
    if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        bPermissionGranted = checkLocationPermission();
    }
    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);





    }
private void setUpMapIfNeeded() {
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();

        if (mMap != null) {


            CameraUpdate center = CameraUpdateFactory.newLatLng(new LatLng(32.065483, 34.824550));
            CameraUpdate zoom = CameraUpdateFactory.zoomTo(10);
            mMap.moveCamera(center);
            mMap.animateCamera(zoom);

        }
    }
}

public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;
public boolean checkLocationPermission(){
    if (ContextCompat.checkSelfPermission(this,
            Manifest.permission.ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED) {

        // Should we show an explanation?
        if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                Manifest.permission.ACCESS_FINE_LOCATION)) {

            // Show an expanation to the user *asynchronously* -- don't block
            // this thread waiting for the user's response! After the user
            // sees the explanation, try again to request the permission.
            //  TODO: Prompt with explanation!

            //Prompt the user once explanation has been shown
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                    MY_PERMISSIONS_REQUEST_LOCATION);

        } else {
            // No explanation needed, we can request the permission.
            ActivityCompat.requestPermissions(this,
                    new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                    MY_PERMISSIONS_REQUEST_LOCATION);
        }
        return false;
    } else {
        return true;
    }
}



 @Override
 public void onRequestPermissionsResult(int requestCode,
                                       String permissions[], int[] grantResults) {
    switch (requestCode) {
        case MY_PERMISSIONS_REQUEST_LOCATION: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                // permission was granted, yay!
                if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED &&
                        ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                    mMap.setMyLocationEnabled(true);
                }
            } else {
                // permission denied, boo! Disable the
                // functionality that depends on this permission.
                Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
            }
            return;
        }

    }
}


@Override
public void onMapReady(final GoogleMap googleMap) {

    mMap=googleMap;

    mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);

    if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        if (bPermissionGranted) {
            //User has previously accepted this permission
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED &&
                    ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                mMap.setMyLocationEnabled(true);
            }
        }
    }
    else {
        //Not in api-23, no need to prompt
        mMap.setMyLocationEnabled(true);
    }

    firebaseRef.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {

            for (DataSnapshot child : dataSnapshot.child("users").getChildren()) {


                String rightLocation = child.child("location_right").getValue().toString();
                String leftLocation = child.child("location_left").getValue().toString();

                double location_left = Double.parseDouble(leftLocation);
                double location_right = Double.parseDouble(rightLocation);
                String party_title = child.child("party/party_title").getValue().toString();
                LatLng cod = new LatLng(location_left, location_right);
                googleMap.addMarker(new MarkerOptions().position(cod).title(party_title));


            }
        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });
}
}

Answer 1

这是我other answer that also requests location updates的简化版。

关键是确保用户在您致电setMyLocationEnabled()之前已授予您权限。

用户在调用onMapReady()时很可能没有接受权限提示（最有可能是首次启动应用程序时），因此setMyLocationEnabled()中有onRequestPermissionsResult()的另一个调用<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" /> <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" /> 1}}在用户接受权限的情况下回调。

首先，确保您拥有AndroidManifest.xml中的权限（在应用程序标记之外）：

public class MapLocationActivity extends AppCompatActivity
        implements OnMapReadyCallback {

    GoogleMap mGoogleMap;
    SupportMapFragment mapFrag;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            checkLocationPermission();
        }

        mapFrag = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mapFrag.getMapAsync(this);
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mGoogleMap = googleMap;
        mGoogleMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);

        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            //User has previously accepted this permission
            if (ActivityCompat.checkSelfPermission(this,
                    Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                mGoogleMap.setMyLocationEnabled(true);
            }
        } else {
            //Not in api-23, no need to prompt
            mGoogleMap.setMyLocationEnabled(true);
        }
    }

    public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;

    public boolean checkLocationPermission() {
        if (ContextCompat.checkSelfPermission(this,
                Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(this,
                    Manifest.permission.ACCESS_FINE_LOCATION)) {

                // Show an expanation to the user *asynchronously* -- don't block
                // this thread waiting for the user's response! After the user
                // sees the explanation, try again to request the permission.
                //  TODO: Prompt with explanation!

                //Prompt the user once explanation has been shown
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                        MY_PERMISSIONS_REQUEST_LOCATION);

            } else {
                // No explanation needed, we can request the permission.
                ActivityCompat.requestPermissions(this,
                        new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                        MY_PERMISSIONS_REQUEST_LOCATION);
            }
            return false;
        } else {
            return true;
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
            case MY_PERMISSIONS_REQUEST_LOCATION: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                    // permission was granted, yay!
                    if (ActivityCompat.checkSelfPermission(this,
                            Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
                        mGoogleMap.setMyLocationEnabled(true);
                    }
                } else {
                    // permission denied, boo! Disable the
                    // functionality that depends on this permission.
                    Toast.makeText(this, "permission denied", Toast.LENGTH_LONG).show();
                }
                return;
            }

        }
    }
}

这是一个适合您的完整Activity类：

{{1}}

如果撤销权限：

它会再次提示：

Answer 2

请在Build.VERSION_CODES之后写N而不是M。

在代码的这一行：

如果（android.os.Build.VERSION.SDK_INT> = Build.VERSION_CODES.N）

对我有用

Android 6上的setMyLocationEnabled（）错误

2 个答案: