再次请求位置权限 onRequestPermissionsResult

Question

我正在尝试构建一个关于 Android N 中权限请求过程的简单示例。

我已经在我的清单文件中声明了ACCESS_COARSE_LOCATION 的用法。我正在尝试在自己的方法中处理请求：

public boolean permissionsChecker() {
        // Here, thisActivity is the current activity
        if (ContextCompat.checkSelfPermission(MainActivity.this,
                Manifest.permission.ACCESS_COARSE_LOCATION)
                != PackageManager.PERMISSION_GRANTED) {

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

                // Show an explanation 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.

            } else {

                // No explanation needed, we can request the permission.

                ActivityCompat.requestPermissions(MainActivity.this,
                        new String[]{Manifest.permission.ACCESS_COARSE_LOCATION},
                        MY_REQUEST_PERMISSION_COARSE_LOCATION);
                return true;

                // MY_PERMISSIONS_REQUEST_READ_CONTACTS is an
                // app-defined int constant. The callback method gets the
                // result of the request.
            }
        }
        return false;

    }

应用程序连接时首先询问此问题：

@Override
    public void onConnected(@Nullable Bundle bundle) {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            if(permissionsChecker()){
                mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
            }
        }
        if(mLastLocation != null){
            Log.i(TAG, mLastLocation.getLatitude() + "");
            Log.i(TAG, mLastLocation.getLongitude() + "");
        } else {
            Log.i(TAG, "Still awaiting permissions, something went wrong");
        }

    }

我的问题是它仍然为 mLastLocation 实例返回 null 并且我能够在调试器中看到它，根据文档，一旦onRequestPermissionsResult() 中有请求代码，我就必须设置所有内容回调，但是当我尝试在其中设置 mLastLocation 实例时，我得到红线告诉我需要发出权限请求：

 @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        switch (requestCode){
            case MY_REQUEST_PERMISSION_COARSE_LOCATION: {
                if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){
                    // permissiosn was granted yaaaay! Do the coarse location related task you need to do
                    //Log.i(TAG, mLastLocation.getLongitude() + "");
                    //Log.i(TAG, mLastLocation.getLatitude() + "");
                    //mLastLocation = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
                } else {
                    // permissions denied, boo! Disable the functionality that depends on this permissions
                }
                return;

                // Still inside the case checker, perform other permissions that this app might require working on
            } // end of case test for the acces coarse location
        } // end of stich statmeent
    } // end of onRequestPermissionsResult()

如果回调会让我再次请求权限，请求权限的目的是什么？我究竟做错了什么？我从文档中得到的东西不多（我知道缺乏经验），并且想知道如何解决这个问题。任何指针和代码建议将不胜感激！

Answer 1

permissionChecker() 的用法看起来像是在扔东西。仅仅因为您请求了权限并不意味着它已被授予。

本次 Droicon 演讲将帮助解释权限模型和用法：https://youtu.be/WGz-alwVh8A

您可能还会发现此库有助于使您的代码更简单、更易于遵循：https://github.com/hiqes/andele