Question

我有一个应用程序，我希望通过在打开活动时删除别针来向用户显示位置＆＃34; Map＆＃34;。我还想显示用户的位置，如果标记出现问题，那么地图就会以用户所在位置为中心。

与其他许多人一样，我有一天注意到我的应用没有显示用户在Android 6.0上方的位置。所以我开始搜索SO和Google并找到一些线程和教程。事实证明，我必须检查权限是否已经可用，或者是否需要通过调用 checkSelfPermissions 方法来授予它们，如果它们尚未被授予，我必须通过调用< EM> requestPermissions 。当他们被请求时，我想设置标记并显示用户位置（或者如果某些内容与附加内容中的标记信息搞混，则将地图置于中心位置）。我想用我的方法setUpMarker做这个。下面是我的 onMapReady （在地图准备就绪时调用）和 onRequestPermissionsResult （当有来自权限请求的用户响应时调用）方法：

public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;

    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        // Permission is not yet available and needs to be asked for
        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION) && ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_COARSE_LOCATION)) {
            // We provide an additional rationale to the user if the permission was not granted
            // and the user would benefit from additional context for the use of the permission.
            // For example if the user has previously denied the permission.
            new AlertDialog.Builder(Map.this)
                    .setMessage("To show the location the permission is needed")
                    .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                        @Override
                        public void onClick(DialogInterface dialog, int which) {
                            ActivityCompat.requestPermissions(Map.this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION, android.Manifest.permission.ACCESS_COARSE_LOCATION}, LOCATION_PERMISSION_REQUEST_ID);
                        }
                    })
                    .setNegativeButton("Cancel", null)
                    .create()
                    .show();
        } else {
            // Permission has not been granted yet. Request it directly.
            ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION, android.Manifest.permission.ACCESS_COARSE_LOCATION}, LOCATION_PERMISSION_REQUEST_ID);
        }

    } else {
        // Permission is already available
        setUpMarker();
    }

}


@Override
public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
    switch (requestCode) {
        case LOCATION_PERMISSION_REQUEST_ID: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                // The permission request was granted, we set up the marker
                setUpMarker();
            } else {
                // The permission request was denied, we make the user aware of why the location is not shown
                Toast.makeText(this,"Since the permission wasn't granted we can't show the location",Toast.LENGTH_LONG).show();
            }
            return;
        }

    }
}

现在，当我想启用用户位置以及何时想要将地图置于用户位置中心时，我的setUpMarker方法仍然出现错误。我得到的错误是：

Call requires permission which may be rejected by user: code should explicitly check to see if permission is available (with 'checkPermission') or explicitly handle a potential 'SecurityException'.

但我已经检查了权限！这是我的setUpMarker：

private void setUpMarker() {
    //HERE I GET THE ERROR
    mMap.setMyLocationEnabled(true); 

    if(!getIntent().getExtras().isEmpty()) {
        // Latitude and longitude was retrieved successfully, set up marker

         ...

    } else {
        // Latitude and longitude was not retrieved, zoom to current location

        LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        Criteria criteria = new Criteria();

        // AND HERE I GET THE ERROR TOO
        Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false)); 
        if (location != null) {
            mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
                    new LatLng(location.getLatitude(), location.getLongitude()), 13));

            CameraPosition cameraPosition = new CameraPosition.Builder()
                    .target(new LatLng(location.getLatitude(), location.getLongitude()))
                    .zoom(17)
                    .bearing(90)
                    .tilt(40)
                    .build();
            mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));

        }

    }
}

如何让应用程序记住权限，或以其他方式解决此问题？我已经检查过类似的线程，但似乎都没有这种问题。

Answer 1

这是Lint错误 - 您可以向该方法添加相同的ContextCompat.checkSelfPermission调用（即使您知道它将始终返回已授予），以取悦Lint或抑制Lint错误。< / p>

Android运行时位置服务权限

1 个答案: