问题

I would like to detect the touch action on a UITextField.

It seems the "Touch Up Inside" action is not fired by touching inside the textfield.

回答1:

It seems "Touch Up Inside" is not enabled for UITextField, but "Touch Down" works.

So the solution is as follows:

Swift 4.x

myTextField.addTarget(self, action: #selector(myTargetFunction), for: .touchDown)
@objc func myTargetFunction(textField: UITextField) {
    print("myTargetFunction")
}

Swift 3.x

myTextField.addTarget(self, action: #selector(myTargetFunction), for: UIControlEvents.touchDown)

@objc func myTargetFunction(textField: UITextField) {
    print("myTargetFunction")
}

回答2:

Swift 4 - 5:

class ViewController: UIViewController, UITextFieldDelegate {
    func textFieldDidBeginEditing(_ textField: UITextField) {
        if textField == myTextField {
            print("You edit myTextField")
        }
    }
}

This is a delegate function.

回答3:

here's Swfit:

and you don't need to use the "touchUpInside" just use the delegate methods like so:

Make your View controller a delegate:

class ViewController: UIViewController, UITextFieldDelegate{

func textFieldDidBeginEditing(textField: UITextField) -> Bool {
    if textField == myTextField {
        return true // myTextField was touched
    }
}

Here's the other delegate methods:

protocol UITextFieldDelegate : NSObjectProtocol {

    optional func textFieldShouldBeginEditing(textField: UITextField) -> Bool // return NO to disallow editing.
    optional func textFieldDidBeginEditing(textField: UITextField) // became first responder
    optional func textFieldShouldEndEditing(textField: UITextField) -> Bool // return YES to allow editing to stop and to resign first responder status. NO to disallow the editing session to end
    optional func textFieldDidEndEditing(textField: UITextField) // may be called if forced even if shouldEndEditing returns NO (e.g. view removed from window) or endEditing:YES called

    optional func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool // return NO to not change text

    optional func textFieldShouldClear(textField: UITextField) -> Bool // called when clear button pressed. return NO to ignore (no notifications)
    optional func textFieldShouldReturn(textField: UITextField) -> Bool // called when 'return' key pressed. return NO to ignore.
}

from swift docs:

struct UIControlEvents : RawOptionSetType {
    init(_ rawValue: UInt)
    init(rawValue: UInt)

    static var TouchDown: UIControlEvents { get } // on all touch downs
    static var TouchDownRepeat: UIControlEvents { get } // on multiple touchdowns (tap count > 1)
    static var TouchDragInside: UIControlEvents { get }
    static var TouchDragOutside: UIControlEvents { get }
    static var TouchDragEnter: UIControlEvents { get }
    static var TouchDragExit: UIControlEvents { get }
    static var TouchUpInside: UIControlEvents { get }
    static var TouchUpOutside: UIControlEvents { get }
    static var TouchCancel: UIControlEvents { get }

    static var ValueChanged: UIControlEvents { get } // sliders, etc.

    static var EditingDidBegin: UIControlEvents { get } // UITextField
    static var EditingChanged: UIControlEvents { get }
    static var EditingDidEnd: UIControlEvents { get }
    static var EditingDidEndOnExit: UIControlEvents { get } // 'return key' ending editing

    static var AllTouchEvents: UIControlEvents { get } // for touch events
    static var AllEditingEvents: UIControlEvents { get } // for UITextField
    static var ApplicationReserved: UIControlEvents { get } // range available for application use
    static var SystemReserved: UIControlEvents { get } // range reserved for internal framework use
    static var AllEvents: UIControlEvents { get }
}

UITextField doesn't respond to "touchUpInside" see to the right side, you'll find it's acceptable control events

回答4:

Update For Swift 3

Here is the code for Swift 3:

myTextField.addTarget(self, action: #selector(myTargetFunction), for: .touchDown)

This is the function:

func myTargetFunction() {
    print("It works!")
}

回答5:

I referred to the UIControlEvents documentation from Apple and came up with the following:

First add UITextFieldDelegate to your class then,

textBox.delegate = self
textBox.addTarget(self, action: #selector(TextBoxOn(_:)),for: .editingDidBegin)
textBox.addTarget(self, action: #selector(TextBoxOff(_:)),for: .editingDidEnd)

with the following functions:

func TextBoxOff(_ textField: UITextField) {
     code
         }                
}

func TextBox(_ textField: UITextField) {
    code
         }
}

回答6:

For Swift 3.1:

1) Create a gesture recognizer:

let textViewRecognizer = UITapGestureRecognizer()

2) Add a handler to the recognizer:

textViewRecognizer.addTarget(self, action: #selector(tappedTextView(_:)))

3) Add the recognizer to your text view:

textView.addGestureRecognizer(textViewRecognizer)

4) Add the handler to your class:

func tappedTextView(_ sender: UITapGestureRecognizer) {
        print("detected tap!")
}

回答7:

To make this a little clearer these things need to be in place. I used this to make it so if a user entered something in an app of my own's credit textField anything in the debit textField is deleted.

UITextFieldDelegate needs to be declared in the View controller i.e class SecondViewController:
The detector functions func myDebitDetector func myCreditDetector need to be in the ViewController class.
put debit.addTarget and credit.addtarget inside view will appear.

@IBOutlet weak var debit: UITextField! and @IBOutlet weak var credit: UITextField! are textfields on the storyboard and connected to the viewController.

class SecondViewController: UIViewController, UIPickerViewDelegate, UIPickerViewDataSource, UITextFieldDelegate {

@IBOutlet weak var credit: UITextField!
@IBOutlet weak var debit: UITextField!

    func myDebitDetector(textfield: UITextField ){
        print("using debit")
        credit.text = ""

    }

    func myCreditDetector(textfield: UITextField) {
        print("using cedit")
        debit.text = ""
    }

    override func viewWillAppear(animated: Bool) {



        debit.addTarget(self, action: "myDebitDetector:", forControlEvents: UIControlEvents.TouchDown)
        credit.addTarget(self, action: "myCreditDetector:", forControlEvents: UIControlEvents.TouchDown)
    ....

    }
}

回答8:

Set the UITextField delegate to your view controller

Obj-C

textField.delegate = self;

Swift

textField.delegate = self

Implement the delegate method

Obj-c

-(void)textField:(UITextField*)textField didBeginEditing {
   // User touched textField
}

Swift

func textFieldDidBeginEditing(textField: UITextField!) {    //delegate method

}

回答9:

Swift 3.0 Version:

textFieldClientName.addTarget(self, action: Selector(("myTargetFunction:")), for: UIControlEvents.touchDown)

回答10:

Swift 4.2.

Try .editingDidEnd instead of .touchDown and delegate.

myTextField.addTarget(self, action: #selector(myTargetFunction), for: .editingDidEnd)

@objc func myTargetFunction(textField: UITextField) {
    print("textfield pressed")
}

回答11:

On xamarin.iOS i easy to use:

YourTextField.WeakDelegate = this;

[...]

[Export("textFieldDidBeginEditing:")]
public void TextViewChanged(UITextField textField)
{
    if (YourTextField.Equals(textField))
        IsYourTextFileFocused = true;
}

来源：https://stackoverflow.com/questions/32261226/ios-swift-how-to-detect-touch-action-on-a-uitextfield

标签

ios

uitextfield

touch-up-inside

iOS/Swift: how to detect touch action on a UITextField

问题