From 2fb956ce67e4bc27f2133b2f52c2d24c95ca9581 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tobias=20L=C3=A4nge?= <tobias.laenge@kit.edu>
Date: Thu, 31 Aug 2023 15:15:23 +0200
Subject: [PATCH] Add permission check to QRCodeImageDialogFragment

- Fix possible NPE on SDK 23-28
---
 .../QRCodeImageDialogFragment.kt              | 39 +++++++++++++++----
 1 file changed, 32 insertions(+), 7 deletions(-)

diff --git a/app/src/main/java/com/secuso/privacyfriendlycodescanner/qrscanner/ui/dialogfragments/QRCodeImageDialogFragment.kt b/app/src/main/java/com/secuso/privacyfriendlycodescanner/qrscanner/ui/dialogfragments/QRCodeImageDialogFragment.kt
index 42d7a79..c9e6d08 100644
--- a/app/src/main/java/com/secuso/privacyfriendlycodescanner/qrscanner/ui/dialogfragments/QRCodeImageDialogFragment.kt
+++ b/app/src/main/java/com/secuso/privacyfriendlycodescanner/qrscanner/ui/dialogfragments/QRCodeImageDialogFragment.kt
@@ -1,12 +1,17 @@
 package com.secuso.privacyfriendlycodescanner.qrscanner.ui.dialogfragments
 
+import android.Manifest
 import android.app.Dialog
+import android.content.pm.PackageManager
 import android.graphics.drawable.BitmapDrawable
+import android.os.Build
 import android.os.Bundle
 import android.widget.Button
 import android.widget.ImageView
 import android.widget.ProgressBar
 import android.widget.Toast
+import androidx.activity.result.contract.ActivityResultContracts
+import androidx.core.content.ContextCompat
 import androidx.fragment.app.DialogFragment
 import androidx.lifecycle.ViewModelProvider
 import com.google.android.material.dialog.MaterialAlertDialogBuilder
@@ -23,7 +28,7 @@ class QRCodeImageDialogFragment : DialogFragment() {
 
     override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
         return activity?.let {
-            val builder = MaterialAlertDialogBuilder(context!!)
+            val builder = MaterialAlertDialogBuilder(requireContext())
             val dialogView = it.layoutInflater.inflate(R.layout.dialog_image_view, null)
             val imageView = dialogView.findViewById<ImageView>(R.id.imageView)
             val progressBar = dialogView.findViewById<ProgressBar>(R.id.progressBar)
@@ -57,18 +62,38 @@ class QRCodeImageDialogFragment : DialogFragment() {
                         context,
                         (imageView.drawable as BitmapDrawable).bitmap
                     )
-                    QRGeneratorUtils.saveCachedImageToExternalStorage(context)
-                    Toast.makeText(
-                        context,
-                        R.string.image_stored_in_gallery,
-                        Toast.LENGTH_LONG
-                    ).show()
+                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && Build.VERSION.SDK_INT <= Build.VERSION_CODES.P) {
+                        if (ContextCompat.checkSelfPermission(requireContext(), Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
+                            activityResultLauncher.launch(Manifest.permission.WRITE_EXTERNAL_STORAGE)
+                        } else {
+                            saveImageToStorage()
+                        }
+                    } else {
+                        saveImageToStorage()
+                    }
                 }
             }
             return dialog
         } ?: throw IllegalStateException("Activity cannot be null")
     }
 
+    private val activityResultLauncher = registerForActivityResult(ActivityResultContracts.RequestPermission()) { isGranted ->
+        if (isGranted) {
+            saveImageToStorage()
+        } else {
+            Toast.makeText(context, "storage permission denied", Toast.LENGTH_LONG).show()
+        }
+    }
+
+    private fun saveImageToStorage() {
+        QRGeneratorUtils.saveCachedImageToExternalStorage(context)
+        Toast.makeText(
+            context,
+            R.string.image_stored_in_gallery,
+            Toast.LENGTH_LONG
+        ).show()
+    }
+
     companion object {
         const val TAG = "QRCodeImageDialog"
     }