permission-handler.md

Runtime Permission Handler

This page outlines the usage of library for providing runtime permission on Android.

Modules

permissions - Includes pure Kotlin implementation of Runtime Permission Handler

permissions-android - Includes android counter part implementation to support Runtime Permission Handler with Android Lifecycles

Features

• Permission - Enumeration with primary types of device permissions
• IPermissionsController - Handler for runtime permission requests can be used in the common code with lifecycle safety for Android
• PermissionDeniedException and PermissionDeniedAlwaysException - Exceptions to handle user denial of permissions

List of supported permissions

• The full list can be found in com.arch.permissions.Permission enum.
  • Camera: Permission.CAMERA
  • Gallery: Permission.GALLERY
  • Storage read: Permission.STORAGE
  • Storage write: Permission.WRITE_STORAGE
  • Fine location: Permission.LOCATION
  • Coarse location: Permission.COARSE_LOCATION
  • Remote notifications: Permission.REMOTE_NOTIFICATION
  • Audio recording: Permission.RECORD_AUDIO

Usage

The AndrioidPermissionController is constructor injected in the viewmodel using HILT.

Presentation Layer

   class ExampleViewModel(
    exceptionHandler: IAndroidExceptionHandler,
    permissionHandler: IAndroidPermissionsController,
    logger: AppLogger) : BaseViewModel(exceptionHandler, permissionHandler, logger) {
    fun requestForGalleryPermission() {
        viewModelScope.launch {
						exceptionHandler.handle { // Automatic Exception Handler
                permissionsController.providePermission(Permission.GALLERY)
                // Permission has been granted successfully.
            } .catch<Exception> {
                val handled: Boolean = when (it) {
                    
                    is PermissionDeniedAlwaysException -> { 
                        // Permission is always denied.
                        // show rational in activity by callback

                        // we tell the exceptionHandler that
                        // we are handling the error by our own & return
                        // true to tell the system to ignore
                        true
                    }
                    
                    is PermissionDeniedException -> {
                      	// Permission was denied.
                      	// show system level default error
                        false
                    }
                    else -> false // here the system is instructed to handle the error
                }
                handled
            }.execute()
        }
    }
}  

App/UI Layer

class ExampleActivity : BaseActivity<ActivityResourceBinding, ExampleViewModel>() {
  	// Here the Baseactivity already binds the permission handler to activity lifecycle.
  
    override val viewModel by viewModels<ExampleViewModel>()

    override fun getLayoutRes() = R.layout.activity_example

    override fun initViewModel(viewModel: ExampleViewModel) {
        binding.viewModel = viewModel
        
       // request the permission from the corresponding viewmodel
        binding.button.setOnClickListener {
            viewModel.requestForGalleryPermission()
        }
    }          
}