Android Runtime Permissions using Dexter

We all know that Android Marshmallow introduced runtime permissions letting user to allow or deny any permission at runtime. Implementing runtime permissions is a tedious process and developer needs to write lot of code just to get a single permission.

In this article, we are going to simplify the process by using Dexter library. Using this library, the permissions can be implemented in few minutes.

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This is an introductory article about the Dexter covering basic features offered by the library. Dexter provides other features like using it with SnackBar, different types of listeners, error handling and few other. You can find more information on Dexter’s developer page.

1. Dexter Permissions Library

To get started with Dexter, add the dependency in your build.gradle

build.gradle


dependencies {
    // Dexter runtime permissions
    implementation 'com.karumi:dexter:6.2.3'
}

1.1 Requesting Single Permission

To request a single permission, you can use withPermission() method by passing the required permission. You also need a PermissionListener callback to receive the state of the permission.

The method onPermissionGranted() will be called once the permission is granted.
onPermissionDenied() will be called when the permission is denied. Here you can check whether the permission is permanently denied by using response.isPermanentlyDenied() condition.

The below example requests CAMERA permission.


Dexter.withContext(this)
            .withPermission(Manifest.permission.CAMERA)
            .withListener(object : PermissionListener {
                override fun onPermissionGranted(response: PermissionGrantedResponse) {
                    // Congrats! permission is granted. You can open the camera row
                    openCamera()
                }

                override fun onPermissionDenied(response: PermissionDeniedResponse) {
                    // check for permanent denial of permission
                    if (response.isPermanentlyDenied) {
                        showSettingsDialog()
                    }
                }

                override fun onPermissionRationaleShouldBeShown(
                    permission: PermissionRequest?,
                    token: PermissionToken
                ) {
                    token.continuePermissionRequest()
                }
            }).check()

1.2 Requesting Multiple Permissions

To request multiple permissions at the same time, you can use withPermissions() method. Below code requests READ_CONTACTS and READ_CALL_LOG permissions.


Dexter.withContext(this)
            .withPermissions(
                Manifest.permission.READ_CONTACTS,
                Manifest.permission.READ_CALL_LOG
            )
            .withListener(object : MultiplePermissionsListener {
                override fun onPermissionsChecked(report: MultiplePermissionsReport) {
                    // check if all permissions are granted
                    if (report.areAllPermissionsGranted()) {
                        Toast.makeText(
                            applicationContext,
                            "All permissions are granted!",
                            Toast.LENGTH_SHORT
                        ).show()
                    }


                    // check for permanent denial of any permission
                    if (report.isAnyPermissionPermanentlyDenied) {
                        // show alert dialog navigating to Settings
                        showSettingsDialog()
                    }
                }

                override fun onPermissionRationaleShouldBeShown(
                    permissions: List<PermissionRequest?>?,
                    token: PermissionToken
                ) {
                    token.continuePermissionRequest()
                }
            })
            .onSameThread()
            .check()

1.3 Error Handling

To catch any errors that occurred while requesting a permission, use PermissionRequestErrorListener.


Dexter.withContext(this)
            .withPermission(Manifest.permission.CAMERA)
            .withListener(object : ....)
            .withErrorListener {error ->
                Toast.makeText(applicationContext, "Error occurred! $error", Toast.LENGTH_SHORT).show();
            }
            .check()

2. Full example

Now let’s see how to use Dexter in an example project.

Create a new project in Android Studio from File ⇒ New Project and select Basic Activity from templates.

Add Dexter dependency to your build.gradle


dependencies {
    // Dexter runtime permissions
    implementation 'com.karumi:dexter:6.2.3'
}

Open strings.xml and add the following strings

strings.xml


<resources>
    <string name="app_name">Runtime Permissions</string>
    <string name="camera_permission">Camera Permission</string>
    <string name="multiple_permissions">Multiple Permissions</string>
    <string name="permissions_title">Need Permissions</string>
    <string name="permissions_message">This app needs permission to use this feature. You can grant them in app settings.</string>
    <string name="cancel">Cancel</string>
    <string name="goto_settings">Go to settings</string>
</resources>

Open the layout file of your main activity activity_main.xml and add two buttons to test different permission methods.

activity_main.xml


<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/main"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="@dimen/default_padding"
    tools:context=".MainActivity">

    <Button
        android:id="@+id/btn_camera_permission"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="@string/camera_permission"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/btn_multiple_permissions"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="@dimen/default_padding"
        android:text="@string/multiple_permissions"
        app:layout_constraintTop_toBottomOf="@id/btn_camera_permission" />

</androidx.constraintlayout.widget.ConstraintLayout>

Open the MainActivity and do the modification as shown below.

Tapping camera button requests camera permission using requestCameraPermission() method.
Tapping request multiple permissions, requests READ_CONTACTS & READ_CALL_LOG permissions using requestMultiplePermissions().
If any permission is permanently denied, calling showSettingsDialog() shows a dialog that navigates to system settings where user can manually grant the permissions.

MainActivity.kt


package info.androidhive.runtime_permissions

import android.Manifest
import android.content.Intent
import android.net.Uri
import android.os.Bundle
import android.provider.MediaStore
import android.provider.Settings
import android.widget.Toast
import androidx.activity.result.contract.ActivityResultContracts
import androidx.appcompat.app.AppCompatActivity
import com.google.android.material.dialog.MaterialAlertDialogBuilder
import com.karumi.dexter.Dexter
import com.karumi.dexter.MultiplePermissionsReport
import com.karumi.dexter.PermissionToken
import com.karumi.dexter.listener.PermissionDeniedResponse
import com.karumi.dexter.listener.PermissionGrantedResponse
import com.karumi.dexter.listener.PermissionRequest
import com.karumi.dexter.listener.multi.MultiplePermissionsListener
import com.karumi.dexter.listener.single.PermissionListener
import info.androidhive.runtime_permissions.databinding.ActivityMainBinding


class MainActivity : AppCompatActivity() {
    private val binding by lazy(LazyThreadSafetyMode.NONE) {
        ActivityMainBinding.inflate(layoutInflater)
    }

    private var requestOpenCamera =
        registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {

        }

    private var requestOpenSettings =
        registerForActivityResult(ActivityResultContracts.StartActivityForResult()) {

        }


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(binding.root)

        binding.btnCameraPermission.setOnClickListener {
            requestCameraPermission()
        }

        binding.btnMultiplePermissions.setOnClickListener {
            requestMultiplePermissions()
        }
    }

    /**
     * Requesting multiple permissions (record audio and location) at once
     * This uses multiple permission model from dexter
     * On permanent denial opens settings dialog
     */
    private fun requestMultiplePermissions() {
        Dexter.withContext(this)
            .withPermissions(
                Manifest.permission.READ_CONTACTS,
                Manifest.permission.READ_CALL_LOG
            )
            .withListener(object : MultiplePermissionsListener {
                override fun onPermissionsChecked(report: MultiplePermissionsReport) {
                    // check if all permissions are granted
                    if (report.areAllPermissionsGranted()) {
                        Toast.makeText(
                            applicationContext,
                            "All permissions are granted!",
                            Toast.LENGTH_SHORT
                        ).show()
                    }


                    // check for permanent denial of any permission
                    if (report.isAnyPermissionPermanentlyDenied) {
                        // show alert dialog navigating to Settings
                        showSettingsDialog()
                    }
                }

                override fun onPermissionRationaleShouldBeShown(
                    permissions: List<PermissionRequest?>?,
                    token: PermissionToken
                ) {
                    token.continuePermissionRequest()
                }
            }).withErrorListener {
                Toast.makeText(
                    applicationContext,
                    "Error occurred! ",
                    Toast.LENGTH_SHORT
                ).show()
            }
            .onSameThread()
            .check()
    }

    /**
     * Requesting camera permission
     * This uses single permission model from dexter
     * Once the permission granted, opens the camera
     * On permanent denial opens settings dialog
     */
    private fun requestCameraPermission() {
        Dexter.withContext(this)
            .withPermission(Manifest.permission.CAMERA)
            .withListener(object : PermissionListener {
                override fun onPermissionGranted(response: PermissionGrantedResponse) {
                    // permission is granted
                    openCamera()
                }

                override fun onPermissionDenied(response: PermissionDeniedResponse) {
                    // check for permanent denial of permission
                    if (response.isPermanentlyDenied) {
                        showSettingsDialog()
                    }
                }

                override fun onPermissionRationaleShouldBeShown(
                    permission: PermissionRequest?,
                    token: PermissionToken
                ) {
                    token.continuePermissionRequest()
                }
            })
            .withErrorListener {error ->
                Toast.makeText(applicationContext, "Error occurred! $error", Toast.LENGTH_SHORT).show();
            }
            .check()
    }

    /**
     * Showing Alert Dialog with Settings option
     * Navigates user to app settings
     * NOTE: Keep proper title and message depending on your app
     */
    private fun showSettingsDialog() {
        MaterialAlertDialogBuilder(this)
            .setTitle(resources.getString(R.string.permissions_title))
            .setMessage(resources.getString(R.string.permissions_message))
            .setNegativeButton(resources.getString(R.string.cancel)) { dialog, which ->
                // Respond to neutral button press
            }
            .setPositiveButton(resources.getString(R.string.goto_settings)) { dialog, which ->
                // Respond to positive button press
                openSettings()
            }
            .show()
    }

    // navigating user to app settings
    private fun openSettings() {
        requestOpenSettings.launch(
            Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS).apply {
                data = Uri.fromParts("package", packageName, null)
            })
    }

    private fun openCamera() {
        requestOpenCamera.launch(Intent(MediaStore.ACTION_IMAGE_CAPTURE))
    }
}

Run the code and see it in action.

Let me know your queries in the comments section below.

Cheers!
Happy Coding 🤗

Android Runtime Permissions using Dexter

1. Dexter Permissions Library

1.1 Requesting Single Permission

1.2 Requesting Multiple Permissions

1.3 Error Handling

2. Full example

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