如何正确地将UITextField设置为第一响应者？ （尝试了3种方法）

Question

Here's the setup:

SNController is an NSObject and it has inside:

1. UIView
2. UITextField
3. UISegmentedControl
4. UILabel
5. UIButton

The view is the same as the view inside the ViewController .

One can be visible at the time. When the UITextField is visible (alpha = 1.0) all the others are invisible (alpha = 0.0).

(1) I perform an animation and I want the text field:

UITextField *textField;

to become the first responder while the animation happens:

[textField becomeFirstResponder];

[UIView animateWithDuration: ...];

Unfortunately it doesn't work.

I've logged the text field and it showed that it cannot become the first responder and I have no idea why...

I've tried another two methods but none of them worked so far:

(2) A complicated way to communicate with the ViewController from the SNController :

Inside the SNController.h/.m :

@property (nonatomic, copy) void(^eventCallBack)();

if (self.eventCallBack) {

    self.eventCallBack();
}

Inside the ViewController.m :

__weak ViewController *self_ = self;

self.restoration.controller.eventCallBack = ^(){

    [self_.restoration.controller.textField becomeFirstResponder];
};

(3) I also tried these methods from inside the SNController :

[self.textField performSelector:@selector(becomeFirstResponder) withObject:nil afterDelay:0.0];

[self.textField performSelectorOnMainThread:@selector(becomeFirstResponder) withObject:nil waitUntilDone:YES];

It just won't give up, it doesn't become the first responder no matter what.

Any ideas?

Answer 1

I realised there was a mistake. There isn't a UITextField inside the SNController but a UIView subclass named SNTextField.

I implemented this method where the UITextField was initialised :

- (void)activateKeyboard
{
    [self.textField becomeFirstResponder];
}

and it worked!