Question

打开MapActivity时，我想让我的地图专注于我当前的位置。我对特定行有疑问：

mMap.setMyLocationEnabled(true);

调用需要用户可能拒绝的权限：代码应明确检查是否可以使用权限（＆＃39; checkPermission＆＃39;）或明确处理潜在的＆＃39; SecurityException＆＃39;。

如何解决此问题？当我搜索这个问题时，我已经阅读了一些内容，但我找不到有用的东西。

这是完整的代码：

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
private static final String FIREBASE_URL="https://haerev.firebaseio.com/";
private Firebase firebaseRef;
private GoogleMap mMap;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps2);
    Firebase.setAndroidContext(this);
    firebaseRef = new Firebase(FIREBASE_URL);


    SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
            .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);
    setUpMapIfNeeded();

}

private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();
        mMap.setMyLocationEnabled(true);
        // Check if we were successful in obtaining the map.
        if (mMap != null) {


            mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() {

                @Override
                public void onMyLocationChange(Location arg0) {
                    // TODO Auto-generated method stub

                    mMap.addMarker(new MarkerOptions().position(new LatLng(arg0.getLatitude(), arg0.getLongitude())).title("It's Me!"));
                }
            });

        }
    }
}

阅读一些评论后，请阅读此问题：http://developer.android.com/training/permissions/requesting.html

我添加了这些内容：

 private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();

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


            if (ActivityCompat.shouldShowRequestPermissionRationale(MapsActivity.this,
                    Manifest.permission.ACCESS_FINE_LOCATION)) {

               checkSelfPermission("You have to accept to enjoy the most hings in this app");
            } else {


                ActivityCompat.requestPermissions(MapsActivity.this,
                        new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
                        MY_PERMISSION_REQUEST_ACCESS_FINE_LOCATION);

            }
        }

        mMap.setMyLocationEnabled(true);
        // Check if we were successful in obtaining the map.
        if (mMap != null) {


            mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() {

                @Override
                public void onMyLocationChange(Location arg0) {
                    // TODO Auto-generated method stub

                    mMap.addMarker(new MarkerOptions().position(new LatLng(arg0.getLatitude(), arg0.getLongitude())).title("It's Me!"));
                }
            });

        }
    }
}

但现在我遇到了一个新问题。它不识别行

＆＃34; MY_PERMISSION_REQUEST_ACCESS_FINE_LOCATION＆＃34;

我想我是以错误的方式使用它。我该怎么用？

Answer 1

经过大量的网络研究，这对我有用：

 private void setUpMapIfNeeded() {
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();
        if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED) {
            mMap.setMyLocationEnabled(true);
        } else {
            Toast.makeText(MapsActivity.this, "You have to accept to enjoy all app's services!", Toast.LENGTH_LONG).show();
            if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                    == PackageManager.PERMISSION_GRANTED) {
                mMap.setMyLocationEnabled(true);
            }
        }

        if (mMap != null) {


            mMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() {

                @Override
                public void onMyLocationChange(Location arg0) {
                    // TODO Auto-generated method stub

                    CameraUpdate center= CameraUpdateFactory.newLatLng(new LatLng(arg0.getLatitude(), arg0.getLongitude()));
                    CameraUpdate zoom=CameraUpdateFactory.zoomTo(12);

                    mMap.moveCamera(center);
                    mMap.animateCamera(zoom);
                }
            });

        }
    }
}

Answer 2

更明确的实施：

    @Override
public void onMapReady(GoogleMap googleMap) {
    MapsInitializer.initialize(getContext());
    mGoogleMap = googleMap;
    if(checkPermission())
    mGoogleMap.setMyLocationEnabled(true);
    else askPermission();
}



 // Check for permission to access Location
    private boolean checkPermission() {
        Log.d(TAG, "checkPermission()");
        // Ask for permission if it wasn't granted yet
        return (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION)
                == PackageManager.PERMISSION_GRANTED );
    }
    // Asks for permission
    private void askPermission() {
        Log.d(TAG, "askPermission()");
        ActivityCompat.requestPermissions(
                getActivity(),
                new String[] { Manifest.permission.ACCESS_FINE_LOCATION },
                REQ_PERMISSION
        );
    }

 @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        Log.d(TAG, "onRequestPermissionsResult()");
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch ( requestCode ) {
            case REQ_PERMISSION: {
                if ( grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED ){
                    // Permission granted
                    if(checkPermission())
                    mGoogleMap.setMyLocationEnabled(true);

                } else {
                    // Permission denied

            }
            break;
        }
    }
}

Answer 3

实际上，这段代码是在我观看解决方案后由Android Studio自动生成的。我正在使用Fragment，所以我不得不将“ this”更改为“ getContext”

try {
        MapsInitializer.initialize(getActivity().getApplicationContext());
    } catch (Exception e) {
        e.printStackTrace();
    }

mMapView.getMapAsync(new OnMapReadyCallback() {
        @Override
        public void onMapReady(GoogleMap mMap) {
            googleMap = mMap;


            if (ActivityCompat.checkSelfPermission(getContext(), Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getContext(),
               Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
               return; 
}

Answer 4

试试这个设置

targetSdkVersion 22

或者请求运行时权限，请参阅此处： - http://coderzpassion.com/android-new-runtime-permissions/ 希望它有助于谢谢

如何解决setMyLocationEnabled权限要求？

4 个答案: