Setup: Fix validation of private keys

For #85

lib/setup/key_editors.dart

@@ -1,53 +1,64 @@
 import 'package:flutter/material.dart';
 
 class PublicKeyEditor extends StatelessWidget {
-  final Function valueChanged;
+  final Key formKey;
+  final TextEditingController _controller;
 
-  PublicKeyEditor(this.valueChanged);
+  PublicKeyEditor(this.formKey, this._controller);
 
   @override
   Widget build(BuildContext context) {
-    return KeyEditor(valueChanged, _validator);
+    return KeyEditor(formKey, _controller, _validator);
   }
 
   String _validator(String val) {
-    if (!val.startsWith("ssh-")) {
-      return "Invalid Public Key";
+    val = val.trim();
+    if (!val.startsWith("ssh-rsa ")) {
+      return "Invalid Public Key - Doesn't start with ssh-rsa";
     }
-    return "";
+    return null;
   }
 }
 
 class PrivateKeyEditor extends StatelessWidget {
-  final Function valueChanged;
+  final Key formKey;
+  final TextEditingController _controller;
 
-  PrivateKeyEditor(this.valueChanged);
+  PrivateKeyEditor(this.formKey, this._controller);
 
   @override
   Widget build(BuildContext context) {
-    return KeyEditor(valueChanged, _validator);
+    return KeyEditor(formKey, _controller, _validator);
   }
 
   String _validator(String val) {
-    if (!val.startsWith("-----BEGIN RSA PRIVATE KEY-----")) {
+    val = val.trim();
+    if (!val.startsWith("-----BEGIN ")) {
       return "Invalid Private Key";
     }
-    if (!val.startsWith("-----END RSA PRIVATE KEY-----")) {
+    if (!val.endsWith("PRIVATE KEY-----")) {
       return "Invalid Private Key";
     }
-    return "";
+
+    return null;
   }
 }
 
 class KeyEditor extends StatelessWidget {
-  final Function valueChanged;
+  final Key formKey;
+  final TextEditingController textEditingController;
   final Function validator;
 
-  KeyEditor(this.valueChanged, this.validator);
+  KeyEditor(this.formKey, this.textEditingController, this.validator) {
+    assert(formKey != null);
+    assert(textEditingController != null);
+    assert(validator != null);
+  }
 
   @override
   Widget build(BuildContext context) {
     var form = Form(
+      key: formKey,
       child: Builder(builder: (context) {
         return TextFormField(
           textAlign: TextAlign.left,
@@ -55,13 +66,7 @@ class KeyEditor extends StatelessWidget {
           style: Theme.of(context).textTheme.body1,
           autovalidate: true,
           validator: validator,
-          onChanged: (String newVal) {
-            if (Form.of(context).validate()) {
-              valueChanged(newVal);
-            } else {
-              valueChanged("");
-            }
-          },
+          controller: textEditingController,
         );
       }),
       autovalidate: true,

lib/setup/sshkey.dart

@@ -207,14 +207,23 @@ class GitHostUserProvidedKeys extends StatefulWidget {
 }
 
 class _GitHostUserProvidedKeysState extends State<GitHostUserProvidedKeys> {
-  String publicKey = "";
-  String privateKey = "";
-  final _publicKeyController = TextEditingController();
-  final _privateKeyController = TextEditingController();
+  GlobalKey<FormState> _publicFormKey;
+  GlobalKey<FormState> _privateFormKey;
+  TextEditingController _publicKeyController;
+  TextEditingController _privateKeyController;
+
+  @override
+  void initState() {
+    super.initState();
+
+    _publicFormKey = GlobalKey<FormState>();
+    _privateFormKey = GlobalKey<FormState>();
+    _publicKeyController = TextEditingController();
+    _privateKeyController = TextEditingController();
+  }
 
   @override
   Widget build(BuildContext context) {
-    var nextEnabled = publicKey.isNotEmpty && privateKey.isNotEmpty;
     return Container(
       child: Column(
         children: <Widget>[
@@ -223,32 +232,35 @@ class _GitHostUserProvidedKeysState extends State<GitHostUserProvidedKeys> {
             style: Theme.of(context).textTheme.headline,
           ),
           const SizedBox(height: 8.0),
-          PublicKeyEditor((String newVal) {
-            setState(() {
-              publicKey = newVal;
-            });
-          }),
+          PublicKeyEditor(_publicFormKey, _publicKeyController),
           const SizedBox(height: 8.0),
           Text(
             "Private Key -",
             style: Theme.of(context).textTheme.headline,
           ),
           const SizedBox(height: 8.0),
-          PrivateKeyEditor((String newVal) {
-            setState(() {
-              privateKey = newVal;
-            });
-          }),
+          PrivateKeyEditor(_privateFormKey, _privateKeyController),
           const SizedBox(height: 16.0),
           GitHostSetupButton(
             text: "Next",
             onPressed: () {
-              if (!nextEnabled) {
+              var publicValid = _publicFormKey.currentState.validate();
+              var privateValid = _privateFormKey.currentState.validate();
+
+              if (!publicValid || !privateValid) {
                 return;
               }
 
               var publicKey = _publicKeyController.text.trim();
+              if (!publicKey.endsWith('\n')) {
+                publicKey += '\n';
+              }
+
               var privateKey = _privateKeyController.text.trim();
+              if (!privateKey.endsWith('\n')) {
+                privateKey += '\n';
+              }
+
               widget.doneFunction(publicKey, privateKey);
             },
           ),