Support sharing via QR code

Another popular format is barcode but unfortunately I cannot seem to find documentations of that anywhere. Feel free to send me.

mobile/build.gradle

@@ -87,6 +87,7 @@ dependencies {
     implementation 'com.jakewharton.timber:timber:4.7.1'
     implementation 'com.linkedin.dexmaker:dexmaker:2.25.0'
     implementation 'com.takisoft.preferencex:preferencex-simplemenu:1.0.0'
+    implementation 'net.glxn.qrgen:android:2.0'
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlinVersion"
     implementation 'org.jetbrains.kotlinx:kotlinx-coroutines-android:1.1.1'
     for (dep in aux) {

mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/configuration/WifiApDialogFragment.kt

@@ -20,6 +20,7 @@ import androidx.core.view.isGone
 import be.mygod.vpnhotspot.AlertDialogFragment
 import be.mygod.vpnhotspot.App.Companion.app
 import be.mygod.vpnhotspot.R
+import be.mygod.vpnhotspot.util.QRCodeDialog
 import be.mygod.vpnhotspot.util.toByteArray
 import be.mygod.vpnhotspot.util.toParcelable
 import kotlinx.android.parcel.Parcelize
@@ -128,14 +129,7 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
 
     private fun populateFromConfiguration(configuration: WifiConfiguration) {
         dialogView.ssid.setText(configuration.SSID)
-        if (!arg.p2pMode) {
-            val selected = configuration.allowedKeyManagement.nextSetBit(0)
-            check(selected >= 0) { "No key management selected" }
-            check(configuration.allowedKeyManagement.nextSetBit(selected + 1) < 0) {
-                "More than 1 key managements supplied"
-            }
-            dialogView.security.setSelection(selected)
-        }
+        if (!arg.p2pMode) dialogView.security.setSelection(configuration.apKeyManagement)
         dialogView.password.setText(configuration.preSharedKey)
         if (Build.VERSION.SDK_INT >= 23) {
             dialogView.band.setSelection(if (configuration.apChannel in 1..165) {
@@ -171,18 +165,25 @@ class WifiApDialogFragment : AlertDialogFragment<WifiApDialogFragment.Arg, WifiA
     override fun beforeTextChanged(s: CharSequence, start: Int, count: Int, after: Int) { }
     override fun afterTextChanged(editable: Editable) = validate()
 
-    override fun onMenuItemClick(item: MenuItem?) = when (item?.itemId) {
-        android.R.id.copy -> {
-            app.clipboard.primaryClip =
-                    ClipData.newPlainText(null, Base64.encodeToString(ret.configuration.toByteArray(), BASE64_FLAGS))
-            true
-        }
-        android.R.id.paste -> {
-            app.clipboard.primaryClip?.getItemAt(0)?.text?.let {
-                populateFromConfiguration(Base64.decode(it.toString(), BASE64_FLAGS).toParcelable())
+    override fun onMenuItemClick(item: MenuItem?): Boolean {
+        return when (item?.itemId) {
+            android.R.id.copy -> {
+                app.clipboard.primaryClip =
+                        ClipData.newPlainText(null, Base64.encodeToString(ret.configuration.toByteArray(), BASE64_FLAGS))
+                true
             }
-            true
+            android.R.id.paste -> {
+                app.clipboard.primaryClip?.getItemAt(0)?.text?.let {
+                    populateFromConfiguration(Base64.decode(it.toString(), BASE64_FLAGS).toParcelable())
+                }
+                true
+            }
+            R.id.share_qr -> {
+                QRCodeDialog().withArg(ret.configuration.toQRString())
+                        .show(fragmentManager ?: return false, "QRCodeDialog")
+                true
+            }
+            else -> false
         }
-        else -> false
     }
 }

mobile/src/main/java/be/mygod/vpnhotspot/net/wifi/configuration/WifiConfiguration.kt

@@ -65,6 +65,35 @@ fun channelToFrequency(channel: Int) = when (channel) {
     else -> throw IllegalArgumentException("Invalid channel $channel")
 }
 
+val WifiConfiguration.apKeyManagement get() = allowedKeyManagement.nextSetBit(0).also { selected ->
+    check(selected >= 0) { "No key management selected" }
+    check(allowedKeyManagement.nextSetBit(selected + 1) < 0) { "More than 1 key managements supplied" }
+}
+
+private val qrSanitizer = Regex("([\\\\\":;,])")
+/**
+ * Documentation: https://github.com/zxing/zxing/wiki/Barcode-Contents#wi-fi-network-config-android-ios-11
+ */
+fun WifiConfiguration.toQRString() = StringBuilder("WIFI:").apply {
+    fun String.sanitize() = qrSanitizer.replace(this) { "\\${it.groupValues[1]}" }
+    var password = true
+    when (apKeyManagement) {
+        WifiConfiguration.KeyMgmt.NONE -> password = false
+        WifiConfiguration.KeyMgmt.WPA_PSK, WifiConfiguration.KeyMgmt.WPA_EAP, WPA2_PSK -> append("T:WPA;")
+        else -> throw IllegalArgumentException("Unsupported authentication type")
+    }
+    append("S:")
+    append(SSID.sanitize())
+    append(';')
+    if (password) {
+        append("P:")
+        append(preSharedKey.sanitize())
+        append(';')
+    }
+    if (hiddenSSID) append("H:true;")
+    append(';')
+}.toString()
+
 /**
  * Based on:
  * https://android.googlesource.com/platform/packages/apps/Settings/+/android-5.0.0_r1/src/com/android/settings/wifi/WifiApDialog.java#88

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

@@ -0,0 +1,26 @@
+package be.mygod.vpnhotspot.util
+
+import android.os.Bundle
+import android.view.LayoutInflater
+import android.view.ViewGroup
+import android.widget.ImageView
+import androidx.core.os.bundleOf
+import androidx.fragment.app.DialogFragment
+import be.mygod.vpnhotspot.R
+import net.glxn.qrgen.android.QRCode
+
+class QRCodeDialog : DialogFragment() {
+    companion object {
+        private const val KEY_ARG = "arg"
+    }
+
+    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?) =
+            ImageView(context).apply {
+                val size = resources.getDimensionPixelSize(R.dimen.qr_code_size)
+                layoutParams = ViewGroup.LayoutParams(size, size)
+                setImageBitmap((QRCode.from(arg).withSize(size, size) as QRCode).bitmap())
+            }
+}

mobile/src/main/res/drawable/ic_social_share.xml

@@ -0,0 +1,6 @@
+<vector android:autoMirrored="true" android:height="24dp"
+    android:viewportHeight="24.0" android:viewportWidth="24.0"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android"
+        android:tint="?attr/colorControlNormal">
+    <path android:fillColor="#FF000000" android:pathData="M18,16.08c-0.76,0 -1.44,0.3 -1.96,0.77L8.91,12.7c0.05,-0.23 0.09,-0.46 0.09,-0.7s-0.04,-0.47 -0.09,-0.7l7.05,-4.11c0.54,0.5 1.25,0.81 2.04,0.81 1.66,0 3,-1.34 3,-3s-1.34,-3 -3,-3 -3,1.34 -3,3c0,0.24 0.04,0.47 0.09,0.7L8.04,9.81C7.5,9.31 6.79,9 6,9c-1.66,0 -3,1.34 -3,3s1.34,3 3,3c0.79,0 1.5,-0.31 2.04,-0.81l7.12,4.16c-0.05,0.21 -0.08,0.43 -0.08,0.65 0,1.61 1.31,2.92 2.92,2.92 1.61,0 2.92,-1.31 2.92,-2.92s-1.31,-2.92 -2.92,-2.92z"/>
+</vector>

mobile/src/main/res/menu/toolbar_configuration.xml

@@ -11,4 +11,8 @@
           android:icon="?attr/actionModePasteDrawable"
           android:title="@android:string/paste"
           app:showAsAction="ifRoom"/>
+    <item android:id="@+id/share_qr"
+          android:icon="@drawable/ic_social_share"
+          android:title="@string/configuration_share"
+          app:showAsAction="ifRoom"/>
 </menu>

mobile/src/main/res/values-zh-rCN/strings.xml

@@ -126,6 +126,7 @@
     <string name="noisy_su_failure">发生异常，详情请查看调试信息。</string>
 
     <string name="configuration_view">设置 WLAN 中继</string>
+    <string name="configuration_share">使用 QR 码分享</string>
     <string name="configuration_rejected">Android 系统拒绝使用此配置。（详情参见日志）</string>
     <string name="wifi_ssid" msgid="5519636102673067319">"网络名称"</string>
     <string name="wifi_security" msgid="6603611185592956936">"安全性"</string>

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

@@ -1,4 +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>
 </resources>

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

@@ -134,6 +134,7 @@
     <string name="noisy_su_failure">Something went wrong, please check the debug information.</string>
 
     <string name="configuration_view">Wi\u2011Fi configuration</string>
+    <string name="configuration_share">Share via QR code</string>
     <string name="configuration_rejected">Android system refuses such configuration. (see logcat)</string>
     <string name="wifi_ssid">Network name</string>
     <string name="wifi_security">Security</string>