如何在新的 ActivityResult API (1.3.0-alpha05) 中获取权限请求？

Posted 2023-04-14

【中文标题】如何在新的 ActivityResult API (1.3.0-alpha05) 中获取权限请求？

【英文标题】：How to get a permission request in new ActivityResult API (1.3.0-alpha05)?

【发布时间】：2020-09-23 21:36:50

【问题描述】：

所以，我尝试使用新的 registerForActivityResult() 方法获得许可，并通过 .launch() 按钮单击请求它，它似乎没有打开任何窗口来请求它。 我总是在 registerForActivityResult() 中得到错误。

    // Permission to get photo from gallery, gets permission and produce boolean
private ActivityResultLauncher<String> mPermissionResult = registerForActivityResult(
        new ActivityResultContracts.RequestPermission(),
        new ActivityResultCallback<Boolean>() 
            @Override
            public void onActivityResult(Boolean result) 
                if(result) 
                    Log.e(TAG, "onActivityResult: PERMISSION GRANTED");
                 else 
                    Log.e(TAG, "onActivityResult: PERMISSION DENIED");
                
            
        );



        // Launch the permission window -- this is in onCreateView()
    floatingActionButton.setOnClickListener(new View.OnClickListener() 
        @Override
        public void onClick(View v) 
         mPermissionResult.launch(Manifest.permission.ACCESS_BACKGROUND_LOCATION);

        
    );

这始终是我的日志：onActivityResult: PERMISSION DENIED

【参考方案1】：

更新 这个答案有效，但我找到了一个更好的权限请求解决方案，没有空洞here。

---

来自docs：

在您的 Activity/Fragment 中，创建此字段：

// Register the permissions callback, which handles the user's response to the
// system permissions dialog. Save the return value, an instance of
// ActivityResultLauncher, as an instance variable.
private ActivityResultLauncher<String> requestPermissionLauncher =
    registerForActivityResult(new RequestPermission(), isGranted -> 
        if (isGranted) 
            // Permission is granted. Continue the action or workflow in your
            // app.
         else 
            // Explain to the user that the feature is unavailable because the
            // features requires a permission that the user has denied. At the
            // same time, respect the user's decision. Don't link to system
            // settings in an effort to convince the user to change their
            // decision.
        
    );

在同一个 Activity/Fragment 中的某处：

if (ContextCompat.checkSelfPermission(
        context, Manifest.permission.ACCESS_BACKGROUND_LOCATION) ==
        PackageManager.PERMISSION_GRANTED) 
    performAction(...);
 else if (shouldShowRequestPermissionRationale(...)) 
    // In an educational UI, explain to the user why your app requires this
    // permission for a specific feature to behave as expected. In this UI,
    // include a "cancel" or "no thanks" button that allows the user to
    // continue using your app without granting the permission.
    showInContextUI(...);
 else 
    // You can directly ask for the permission.
    // The registered ActivityResultCallback gets the result of this request.
    requestPermissionLauncher.launch(Manifest.permission.ACCESS_BACKGROUND_LOCATION);

如果您一直收到不合理的“Permission denied”，可能是您没有在manifest.xml 中声明？

【讨论】：

权限被拒绝和带有“不再询问”选项的情况如何？？？

有什么方法可以检查用户是否永久拒绝？显示相关消息。

@VishakAKamath 这个答案是从链接的文档中复制的。在练习了更多之后，我想出了一种更简洁、更好的权限请求流程方法。查看this 以获取您所有问题的答案。

@MarlonLópez 检查我上面链接的答案或here

【参考方案2】：

看着Update to androidx.fragment:fragment:1.3.0-alpha08: registerForActivityResult not allowed after onCreate anymore. How to use after onCreate?，

private lateinit var checkLocationPermission: ActivityResultLauncher<Array<String>>

// Initialize checkLocationPermission in onAttach or onCreate.
override fun onCreate(savedInstanceState: Bundle?) 
    super.onCreate(savedInstanceState)

    checkLocationPermission = registerForActivityResult(
        ActivityResultContracts.RequestMultiplePermissions())  permissions ->
        if (permissions[Manifest.permission.ACCESS_FINE_LOCATION] == true ||
            permissions[Manifest.permission.ACCESS_COARSE_LOCATION] == true) 
            initUserLocation()
         else 
            // Permission was denied. Display an error message.
        
    


fun showMap() 
    if (ActivityCompat.checkSelfPermission(requireContext(),
        Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED ||
        ActivityCompat.checkSelfPermission(requireContext(),
            Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) 
        initUserLocation()
     else 
        checkLocationPermission.launch(arrayOf(Manifest.permission.ACCESS_FINE_LOCATION,
            Manifest.permission.ACCESS_COARSE_LOCATION))
    


private fun initUserLocation() 
    googleMap?.isMyLocationEnabled = true