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@interface LoginViewController () | |
@property (strong, nonatomic) RACSubject *textFieldReturnPressed; | |
@property (strong, nonatomic) UITextField *usernameTextField; | |
@property (strong, nonatomic) UITextField *passwordTextField; | |
@end | |
@implementation LoginViewController | |
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil { | |
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; | |
if (self) { | |
_textFieldReturnPressed = [RACSubject subject]; | |
} | |
return self; | |
} | |
- (void)viewDidLoad { | |
[super viewDidLoad]; | |
[self addSubview:self.usernameTextField]; | |
[self addSubview:self.passwordTextField]; | |
RACSignal *validUsername = [self.usernameTextField.rac_textSignal map:^(NSString *username) { | |
return @(username.length > 0 && [username isAValidEmail]); | |
}]; | |
RACSignal *validPassword = [self.passwordTextField.rac_textSignal map:^(NSString *password) { | |
return @(password.length > 0); | |
}]; | |
[[self.textFieldReturnPressed combineLatestWith:validUsername] subscribeNext:^(RACTuple *values) { | |
RACTupleUnpack(UITextField *textField, NSNumber *validity) = values; | |
if (validity.boolValue && [textField isEqual:self.usernameTextField]) { | |
[self.passwordTextField becomeFirstResponder]; | |
} | |
}]; | |
[[self.textFieldReturnPressed combineLatestWith:validPassword] subscribeNext:^(RACTuple *values) { | |
RACTupleUnpack(UITextField *textField, NSNumber *validity) = values; | |
if (validity.boolValue && [textField isEqual:self.passwordTextField]) { | |
// start log in process | |
} | |
}]; | |
} | |
- (BOOL)textFieldShouldReturn:(UITextField *)textField { | |
[self.textFieldReturnPressed sendNext:textField]; | |
return YES; | |
} | |
// other implementation details skipped... | |
@end |
So you only want your login process to start when the form is valid, correct?
One way to think about it is that you want to sequence the check for validity after the return.
You could do something like:
[[[[[self.textFieldReturnPressed
filter:^ BOOL (UITextField *field) {
@strongify(self);
return field == self.passwordTextField;
}]
sequenceMany:^{
return validPassword;
}]
filter:^(NSNumber *valid) {
return valid.boolValue;
}]
subscribeNext:^(id _) {
// do some login stuff
}];
But you probably want to check the whole validity of the form, not just the password:
RACSignal *formValid = [RACSignal
combineLatest:@[ validPassword, validUsername ]
reduce:^(NSNumber *validPassword, NSNumber *validUsername) {
return validPassword.boolValue && validUsername.boolValue;
}];
Hopefully that helps!
Right now, I'm just trying to execute the code on line #34 - basically switch the focus from username text field to password text field when the user hits return (and if the input is correct, as determined by the validUsername
signal).
The problem with my code is that because it's using combineWithLatest:
, the beginFirstResponder
is executed too often. I've tried to adapt the piece of code you suggested to this task, but it has the same effect.
I have this view controller.
I want to combine a signal that checks the validity of the input (e.g.
validUsername
orvalidPassword
) with thetextFieldReturnPressed
which is sent intextFieldShouldReturn:
.The problem with this code above is that
combineLatestWith:
is triggered too often (on every change of a text field). What I need is a method similar to combineLatestWith: but without this call to sendNext(), i.e. one that would produce a new signal only when the receiver changes.Alternatively, is there a better way to implement this behavior?