Xamarin iOS - Navigate to next text field with return key - ios

Question

I couldn't find anything in the Xamarin documentation about navigating to the next text field in a series of text fields on a form, only a small tutorial on removing the keyboard.
To keep things simple I am using a txtUsername(tag 1) text field and a txtPassword(tag 2) text field. When I implement the following code, it isn't transferring to Xamarin Studio. Does anyone know the way this can be done code in Xamarin Studio, or alternatively if I can transfer the code from XCode to Xamarin Studio.
I am using the following code:
- (BOOL)textFieldShouldReturn:(UITextField *)txtUsername{
NSLog(#"textFieldShouldReturn:");
if (txtUsername.tag == 1) {
UITextField *txtPassword= (UITextField *)[self.view viewWithTag:2];
[txtPassword becomeFirstResponder];
}
else {
[txtUsername resignFirstResponder];
}
return YES;
}
Thanks in advance

Answer 1

I think that the simplest way to do this is using the ShouldReturn method on your UITextFields with the BecomeFirstResponder method. For example, for a login form with Username and Password UITextFields, as follows (in your ViewDidLoad method):
Username = new UITextField();
Username.ReturnKeyType = UIReturnKeyType.Next;
Username.KeyboardType = UIKeyboardType.EmailAddress;
Username.ShouldReturn = (tf) =>
{
Password.BecomeFirstResponder();
return true;
};
View.Add(Username);
Password = new UITextField();
Password.SecureTextEntry = true;
Password.ReturnKeyType = UIReturnKeyType.Go;
Password.ShouldReturn = (tf) =>
{
// Do your login
return true;
};
View.Add(Password);
When you click next when the Username is active, it moves to the Password field. Clicking Go in the password field submits the form.

Answer 2

I wrote a generic solution for every form (not only those with 2 fields).
I´ve got a BaseViewController with these methods:
private UITextField[] formTextfields;
protected void EnableNextKeyForTextFields(UITextField[] fields)
{
formTextfields = fields;
foreach (var field in fields)
{
field.ShouldReturn += ShouldReturn;
}
}
private bool ShouldReturn(UITextField textField)
{
int index = Array.IndexOf(formTextfields, textField);
if (index > -1 && index < formTextfields.Length - 1)
{
formTextfields[index + 1].BecomeFirstResponder();
return true;
}
else if (index == formTextfields.Length - 1)
{
formTextfields[index].ResignFirstResponder();
FormFinished();
}
return false;
}
protected virtual void FormFinished()
{
// this should be implemented on viewControllers using "EnableNextKeyForTextFields"
}
Then, in your view implementation, you just need to pass all your textfields in a single array:
EnableNextKeyForTextFields(new UITextField[] { NameField, SurnameField, EmailField, PasswordField });
When the users clicks "return" when editing the last field of the array, the method "FormFinished" will be called, so you can override it in your implementation:
protected override void FormFinished()
{
(ViewModel as RegisterViewModel).Register(); // or whatever you need to do here
}
I hope this is useful for somebody

Answer 3

You could make use of these functions
http://iosapi.xamarin.com/?link=M%3aMonoTouch.UIKit.UIResponder.BecomeFirstResponder
BecomeFirstResponder()
and
http://iosapi.xamarin.com/?link=M%3aMonoTouch.UIKit.UIResponder.ResignFirstResponder
ResignFirstResponder()
According to the documentation you should add the textField Delegate method like this
public virtual bool ShouldReturn (UITextField textField)
{
if (txtUsername.tag == 1) {
UITextField txtPassword = (UITextField)this.view.ViewWithTag(2);
txtPassword.BecomeFirstResponder();
}
else {
txtUsername.ResignFirstResponder();
}
return true;
}

Answer 4

Here's a sample of how to implement in Xamarin.iOS. There may be other simpler ways to do this but I couldn't find any, and this works for me.
I subclassed UITextFieldDelegate to add a custom event handler, then created an instance of it in my view controller code, assigned a lambda expression to the custom event handler so I could access instance variables, and set this delegate instance as the Delegate on my 2 ext fields:
public class LoginTextFieldDelegate : UITextFieldDelegate
{
public EventHandler<UITextField> OnShouldReturn;
public override bool ShouldReturn(UITextField textField)
{
if (OnShouldReturn != null)
{
OnShouldReturn(this, textField);
}
return true;
}
}
Then in my view controller ViewDidLoad method:
var textDelegate = new LoginTextFieldDelegate
{
OnShouldReturn = (sender, textField) =>
{
if (textField.Tag == txtEmailAddress.Tag)
{
txtPassword.BecomeFirstResponder();
}
else if (textField.Tag == txtPassword.Tag)
{
txtPassword.ResignFirstResponder();
}
}
};
txtEmailAddress.Delegate = textDelegate;
txtPassword.Delegate = textDelegate;
Don't forget to set a distinct tag on each UITextField in code / Interface Builder!

Answer 5

Could be easier to use the class available here
public override void ViewDidLoad ()
{
base.ViewDidLoad ();
// Manage keyboard and tab order
new [] {
usernameField, // Tab order = 0
passwordField, // Tab order = 1
emailField // Tab order = 2
}.InitializeNavigationOnFields();
}
Just call the method passing all the text fields in the order you want them to be navigated through the keyboard.

Answer 6

I recently implemented a solution on a Sign In Screen that handles the question in quite a simple and precise manner.
Not sure if these properties and events existed when the question was first asked but they will help out now for anyone else who needs it.
Entry emailEntry = new Entry()
{
Keyboard = Keyboard.Email,
ReturnType = ReturnType.Next //Changes Return Button on Keyboard to 'Next'
};
emailEntry.Completed += (s, e) => passwordEntry.Focus();
The Completed event fires when the Return Key is pressed. I then set the Focus to my passwordEntry field.
Entry passwordEntry = new Entry()
{
IsPassword = true,
ReturnType = ReturnType.Go //Changes Return Button on Keyboard to 'Next'
};
passwordEntry.Completed += (s, e) => SignInClick(s, e); //SignInClick method handles the sign in functionality
The Completed event for the password entry then initiates the SignInClick method which was previously only handled by a button on the screen.