Find out when UIKeyboard.frame intersects with other frame?

问题

I need to find out when the textfield becomes the first responder to notify me whether the keyboard that's going to show will obstruct the UITextField. If it does, I wanna adjust the scrollview properties.

So far I have this setup. I'm listening for UIKeyboardWillShow notifications that calls the following selector:

func keyboardWillAppear(notification:NSNotification)
{
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
    {

        if keyboardSize.intersects(textField.frame)
        {
            print("It intersects")
        }
        else
        {
            print("Houston, we have a problem")
        }
    }

Note: I tried with UIKeyboardDidShow but still no success. UITextField is a subview of the scrollView.

回答1:

listen to size changes of the keyboard
CONVERT the coordinates

working sample:

 @IBOutlet weak var textView: UITextView!
 override func viewDidLoad() {
    super.viewDidLoad()

    //keyboard observers
    NotificationCenter.default.addObserver(self, selector: #selector(keyboardWillChange), name: NSNotification.Name.UIKeyboardWillChangeFrame, object: nil)
}

func keyboardWillChange(notification:NSNotification)
{
    print("Keyboard size changed")

    if let keyboardSize = notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? CGRect {
        //convert gotten rect
        let r = self.view.convert(keyboardSize, from: nil)

        //test it
        if r.intersects(textView.frame) {
            print("intersects!!!")
        }
    }
}

回答2:

How about comparing the start position of the keyboard with the end position of the text?

working sample:

func keyboardWillAppear(notification:NSNotification)
{
    if let keyboardSize = (notification.userInfo?[UIKeyboardFrameEndUserInfoKey] as? NSValue)?.cgRectValue
    {
        if keyboardSize.origin.y < textField.frame.origin.y + textField.frame.size.height {
             print("It intersects")
        } else {
            print("Houston, we have a problem")
        }
    }
}

来源：https://stackoverflow.com/questions/42231283/find-out-when-uikeyboard-frame-intersects-with-other-frame

标签

swift

swift3

uitextfield

uikit