Fix Wi-Fi QR code with non-ISO chars

mobile/build.gradle

@@ -88,10 +88,10 @@ dependencies {
     implementation 'com.android.billingclient:billing:2.0.3'
     implementation 'com.github.topjohnwu.libsu:core:2.5.1'
     implementation 'com.google.android.material:material:1.1.0-beta02'
+    implementation 'com.google.zxing:core:3.4.0'
     implementation 'com.jakewharton.timber:timber:4.7.1'
     implementation 'com.linkedin.dexmaker:dexmaker:2.25.1'
     implementation 'com.takisoft.preferencex:preferencex-simplemenu:1.1.0'
-    implementation 'net.glxn.qrgen:android:2.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlinVersion"
     implementation 'org.jetbrains.kotlinx:kotlinx-collections-immutable:0.3'
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.3.2-1.3.60'

mobile/src/main/java/be/mygod/vpnhotspot/util/QRCodeDialog.kt

@@ -1,26 +1,53 @@
 package be.mygod.vpnhotspot.util
 
+import android.graphics.Bitmap
+import android.graphics.Color
 import android.os.Bundle
 import android.view.LayoutInflater
 import android.view.ViewGroup
 import android.widget.ImageView
+import android.widget.Toast
 import androidx.core.os.bundleOf
 import androidx.fragment.app.DialogFragment
 import be.mygod.vpnhotspot.R
-import net.glxn.qrgen.android.QRCode
+import com.google.zxing.BarcodeFormat
+import com.google.zxing.EncodeHintType
+import com.google.zxing.MultiFormatWriter
+import com.google.zxing.WriterException
+import timber.log.Timber
+import java.nio.charset.StandardCharsets
 
+/**
+ * Based on:
+ * https://android.googlesource.com/platform/packages/apps/Settings/+/0d706f0/src/com/android/settings/wifi/qrcode/QrCodeGenerator.java
+ * https://android.googlesource.com/platform/packages/apps/Settings/+/8a9ccfd/src/com/android/settings/wifi/dpp/WifiDppQrCodeGeneratorFragment.java#153
+ */
 class QRCodeDialog : DialogFragment() {
     companion object {
         private const val KEY_ARG = "arg"
+        private val iso88591 = StandardCharsets.ISO_8859_1.newEncoder()
     }
 
     fun withArg(arg: String) = apply { arguments = bundleOf(KEY_ARG to arg) }
     private val arg get() = arguments?.getString(KEY_ARG)
 
-    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?) =
+    override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?) = try {
-            ImageView(context).apply {
+        ImageView(context).apply {
-                val size = resources.getDimensionPixelSize(R.dimen.qr_code_size)
+            val hints = HashMap<EncodeHintType, Any>()
-                layoutParams = ViewGroup.LayoutParams(size, size)
+            if (!iso88591.canEncode(arg)) hints[EncodeHintType.CHARACTER_SET] = StandardCharsets.UTF_8.name()
-                setImageBitmap((QRCode.from(arg).withSize(size, size) as QRCode).bitmap())
+            val size = resources.getDimensionPixelSize(R.dimen.qrcode_size)
+            val qrBits = MultiFormatWriter().encode(arg, BarcodeFormat.QR_CODE, size, size, hints)
+            val bitmap = Bitmap.createBitmap(size, size, Bitmap.Config.RGB_565)
+            for (x in 0 until size) for (y in 0 until size) {
+                bitmap.setPixel(x, y, if (qrBits.get(x, y)) Color.BLACK else Color.WHITE)
             }
+            layoutParams = ViewGroup.LayoutParams(size, size)
+            setImageBitmap(bitmap)
+        }
+    } catch (e: WriterException) {
+        Timber.w(e)
+        Toast.makeText(context, e.readableMessage, Toast.LENGTH_LONG).show()
+        dismiss()
+        null
+    }
 }

mobile/src/main/res/values/dimen.xml

@@ -1,5 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
 <resources>
     <dimen name="listitem_manage_tether_padding_start">56dp</dimen>
-    <dimen name="qr_code_size">250dp</dimen>
+    <dimen name="qrcode_size">264dp</dimen>
 </resources>