Fixed possibility to add duplicate servers in DNS settings.

app/src/main/java/eu/neilalexander/yggdrasil/DnsActivity.kt

@@ -60,13 +60,17 @@ class DnsActivity : AppCompatActivity() {
             builder.setTitle(getString(R.string.dns_add_server_dialog_title))
             builder.setView(view)
             builder.setPositiveButton(getString(R.string.add)) { dialog, _ ->
-                servers.add(input.text.toString())
+                val server = input.text.toString()
+                if (!servers.contains(server)) {
+                    servers.add(server)
                     preferences.edit().apply {
                         putString(KEY_DNS_SERVERS, servers.joinToString(","))
                         commit()
                     }
-                dialog.dismiss()
                     updateConfiguredServers()
+                } else {
+                    Toast.makeText(this, R.string.dns_already_added_server, Toast.LENGTH_SHORT).show()
+                }
             }
             builder.setNegativeButton(getString(R.string.cancel)) { dialog, _ ->
                 dialog.cancel()
@@ -158,12 +162,17 @@ class DnsActivity : AppCompatActivity() {
             addButton.tag = server
 
             addButton.setOnClickListener { button ->
-                servers.add(button.tag as String)
+                val serverString = button.tag as String
+                if (!servers.contains(serverString)) {
+                    servers.add(serverString)
                     preferences.edit().apply {
                         this.putString(KEY_DNS_SERVERS, servers.joinToString(","))
                         this.commit()
                     }
                     updateConfiguredServers()
+                } else {
+                    Toast.makeText(this, R.string.dns_already_added_server, Toast.LENGTH_SHORT).show()
+                }
             }
             view.setOnLongClickListener {
                 val builder: AlertDialog.Builder = AlertDialog.Builder(this)

app/src/main/res/values-ru/strings.xml

@@ -22,6 +22,7 @@
     <string name="dns_one_server">1 сервер</string>
     <string name="dns_many_servers">%d сервера/серверов</string>
     <string name="dns_remove_title">Убрать %s?</string>
+    <string name="dns_already_added_server">Этот сервер уже добавлен.</string>
     <string name="main_no_connectivity">Включено (Нет подключения)</string>
     <string name="main_enabled">Подключено</string>
     <string name="main_disabled">Выключено</string>

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

@@ -22,6 +22,7 @@
     <string name="dns_one_server">1 server</string>
     <string name="dns_many_servers">%d server</string>
     <string name="dns_remove_title">Remove %s?</string>
+    <string name="dns_already_added_server">This server is already added.</string>
     <string name="main_no_connectivity">Enabled (No connectivity)</string>
     <string name="main_enabled">Connected</string>
     <string name="main_disabled">Not enabled</string>