Keyboard not appear when touch over UITextField - ios

Question

I created a simple UIView with a UILabel and a UITextField inside of this UIView, this appear fine in the screen but when I touch over the UITextField, the keyboard doesn't appear.
I'm using autolayout programmatic and I'm think the problem is something about UIVIew frame.
I made a simple code to simulate this problem, the most relevant part of code is:
FormInput interface.
//FormInput.h
#import <UIKit/UIKit.h>
#interface FormInput : UIView
#property (nonatomic, strong) NSString *title;
#end
FormInput implementation
// FormInput.m
#import "FormInput.h"
#interface FormInput () <UITextFieldDelegate>
#property (nonatomic, strong) UILabel *label;
#property (nonatomic, strong) UITextField *field;
- (void)setuSubviews;
#end
#implementation FormInput
- (id)init
{
self = [super init];
if(!self) return nil;
[self setuSubviews];
return self;
}
- (void)setuSubviews
{
NSDictionary *views = #{
#"label":self.label,
#"field":self.field
};
[self addSubview:self.label];
[self addSubview:self.field];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|-0-[label(<=120)]-2-[field]-0-|" options:0 metrics:nil views:views]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|-0-[label]" options:0 metrics:nil views:views]];
[self addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|-0-[field]" options:0 metrics:nil views:views]];
}
#pragma mark - Lazy properties
- (UILabel *)label
{
if(!_label)
{
_label = [UILabel new];
_label.textColor = [UIColor blackColor];
_label.translatesAutoresizingMaskIntoConstraints = NO;
}
return _label;
}
- (UITextField *)field
{
if(!_field)
{
_field = [UITextField new];
_field.translatesAutoresizingMaskIntoConstraints = NO;
_field.font = [UIFont systemFontOfSize:16];
_field.placeholder = #"enter text here";
_field.keyboardType = UIKeyboardTypeDefault;
_field.keyboardAppearance = UIKeyboardAppearanceDark;
_field.returnKeyType = UIReturnKeyDone;
_field.clearButtonMode = UITextFieldViewModeWhileEditing;
_field.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
}
return _field;
}
#pragma mark - Properties setters
- (void)setTitle:(NSString *)title
{
_title = title;
self.label.text = title;
}
#end
View controller
#import "ViewController.h"
#import "FormInput.h"
#interface ViewController ()
#property (nonatomic, strong) FormInput *username;
#property (nonatomic, strong) FormInput *email;
- (void)setupLayout;
#end
#implementation ViewController
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.view.backgroundColor = [UIColor whiteColor];
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
- (void)viewWillAppear:(BOOL)animated
{
[super viewWillAppear:animated];
// [self setupLayout];
}
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
[self setupLayout];
}
#pragma mark - Lazy properties
- (FormInput *)username
{
if(!_username)
{
_username = [FormInput new];
_username.translatesAutoresizingMaskIntoConstraints = NO;
_username.title = #"Username:";
}
return _username;
}
- (FormInput *)email
{
if(!_email)
{
_email = [FormInput new];
_email.translatesAutoresizingMaskIntoConstraints = NO;
_email.title = #"Email:";
}
return _email;
}
#pragma mark - Layout setup
- (void)setupLayout
{
UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];
btn.translatesAutoresizingMaskIntoConstraints = NO;
[btn setTitle:#"Button" forState:UIControlStateNormal];
UITextField *field = [UITextField new];
field.translatesAutoresizingMaskIntoConstraints = NO;
field.placeholder = #"Placeholder";
[self.view addSubview:self.username];
[self.view addSubview:self.email];
[self.view addSubview:btn];
[self.view addSubview:field];
NSDictionary *views = #{
#"username" : self.username,
#"email" : self.email,
#"btn" : btn,
#"field" : field
};
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|-[username]-|" options:0 metrics:nil views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|-[email]-|" options:0 metrics:nil views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|-[btn]-|" options:0 metrics:nil views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"H:|-[field]-|" options:0 metrics:nil views:views]];
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|-30-[username]-30-[email]-30-[btn]-30-[field]" options:0 metrics:nil views:views]];
}
#end

Answer 1

Make sure parent containers of the text field in question have "User Interaction Enabled" checked. Maybe you checked it for the text field but not your viewcont?
My reputation is "1" and I can't poste an image, but this check button should be in the interaction part...

Answer 2

Ok I found the reason.
The height of each view in the constraint below still intrinsic:
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|-30-[username]-30-[email]-30-[btn]-30-[field]" options:0 metrics:nil views:views]]
Thus, just add a vertical height for each view in the constraint visual format below.
[self.view addConstraints:[NSLayoutConstraint constraintsWithVisualFormat:#"V:|-30-[username(20)]-30-[email(20)]-30-[btn]-30-[field]" options:0 metrics:nil views:views]]
Not trivial but this makes the views inside added view to responds touch actions.
Thanks!