Android运行时位置服务权限

Question

我有一个应用程序，我想通过在打开活动“地图”时放下一个别针来向用户显示位置。我还想显示用户的位置，如果从附加信息中提供的信息出现问题，地图将以用户位置为中心。

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的位置高于Android 6.0。所以我开始搜索SO和Google，并找到了一些线程和教程。原来，我必须检查权限是否已经可用或者是否需要通过调用方法checkSelfPermissions来授予，如果它们没有被授予，我必须通过调用requestPermissions来请求它们。当他们被请求时，我想设置标记并显示用户的位置（或者如果某件事与来自额外设备的标记信息混淆在一起，请将它放在中心位置）。我想用我的方法setUpMarker来做到这一点。下面是我onMapReady（称为图时已准备就绪）和onRequestPermissionsResult（当从许可请求的用户响应调用）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，我仍然在我的setUpMarker得到一个错误方法当我想启用用户的位置，当我想要在用户的位置中心地图。我得到的错误是这样的：

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'. 

但我已经检查过权限！这里是我的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)); 

     } 

    } 
} 

我该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，但没有一个似乎有这种问题。

Answer 1

这是一个Lint错误 - 您可以将相同的ContextCompat.checkSelfPermission调用添加到该方法（即使您知道它总是会返回授予的），以请Lint或抑制Lint错误。