Helper

PermissionHelper.kt

import android.app.Activity
import android.content.Context
import android.content.Intent
import android.content.pm.PackageManager
import android.net.Uri
import android.provider.Settings
import androidx.core.app.ActivityCompat
import androidx.core.content.ContextCompat


class PermissionHelper private constructor(
    val requestCode: Int,
    val permissions: Set<String>,
    val listener: IPermissionRequest
) {

    companion object {
        fun openPermissionSettings(context: Context) {
            val intent = Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS)
            val uri: Uri = Uri.fromParts("package", context.packageName, null)
            intent.data = uri
            context.startActivity(intent)
        }
    }

    fun requestPermission(activity: Activity) {
        val permissionsNotGranted = permissions.filter { ContextCompat.checkSelfPermission(this, it) != PackageManager.PERMISSION_GRANTED }
        if (permissionsNotGranted.isNotEmpty()) {
            val isAnyNeededExplainWhyNeedsPermission = permissionsNotGranted.any {
                ActivityCompat.shouldShowRequestPermissionRationale(
                    activity,
                    it
                )
            }

            if (isAnyNeededExplainWhyNeedsPermission) {
                listener.expainToUserWhyWeNeedPermission(requestCode)
            } else {
                ActivityCompat.requestPermissions(
                    activity,
                    permissions.toTypedArray(),
                    requestCode
                )
            }
        }
    }

    fun onRequestPermissionsResult(
        requestCode: Int,
        grantResults: IntArray
    ) {
        if (requestCode != this.requestCode)
            return

        val isAllPermissionsGranted = grantResults.all { it == PackageManager.PERMISSION_GRANTED }

        if (isAllPermissionsGranted)
            listener.userGrantedPermission(requestCode)
        else
            listener.userDeniedPermission(requestCode)

    }

    interface IPermissionRequest {
        /**
         * Gets called when user grant permission.
         *
         * @param requestCode Request COde.
         */
        fun userGrantedPermission(requestCode: Int)

        /**
         * Gets called when user denied permission.
         *
         * @param requestCode Request Code.
         */
        fun userDeniedPermission(requestCode: Int)

        /**
         * Get called if we need to show expaination to user why we need this permission.
         * todo: need to implement when should call this
         *
         * @param requestCode Request Code.
         */
        fun expainToUserWhyWeNeedPermission(requestCode: Int)
    }

    class Builder {
        private val permissions: MutableSet<String> = mutableSetOf()
        private var listener: IPermissionRequest? = null

        fun addPermission(permission: String): Builder {
            permissions.add(permission)
            return this
        }

        fun addListener(listener: IPermissionRequest): Builder {
            this.listener = listener
            return this
        }

        fun build(requestCode: Int): PermissionHelper {
            return PermissionHelper(requestCode, permissions, listener!!)
        }
    }

}