当键盘出现Swift时发出移动视图

Question

I am using a scroll view and auto layout to move the view when the keyboard appears and hides one of my text input elements. To do so I am using the below functions.

The issue is that I can't get it to work for both the text field and text view. I have researched a lot and tried implementing all answers I have found on SO and other resources but most answers only deal with single text fields not multiple and I have not found a single solution for a text field and a text view.

I know that the below code is designed for text fields but I am trying to modify it to work with text views as well because out of all the different ways I haver seen to move the view when the keyboard appears this works the best for me.

I am wondering if there is a way to get the view to move for both my text field and text view using my current code. Also Im wondering if this is the best way to be moving the view.

Functions to move the view when keyboard appears:

func keyboardWillShow(sender: NSNotification) {
    let info: NSDictionary = sender.userInfo!
    let value: NSValue = info.valueForKey(UIKeyboardFrameBeginUserInfoKey) as! NSValue
    let keyboardSize: CGSize = value.CGRectValue().size
    let contentInsets: UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize.height + 20, 0.0)
    scrollView.contentInset = contentInsets

    var aRect: CGRect = self.view.frame
    aRect.size.height -= keyboardSize.height
    let activeTextFieldRect: CGRect? = myTextField?.frame
    let activeTextFieldOrigin: CGPoint? = activeTextFieldRect?.origin
    if (!CGRectContainsPoint(aRect, activeTextFieldOrigin!)) {
        scrollView.scrollRectToVisible(activeTextFieldRect!, animated:true)
    }
}

func keyboardWillHide(sender: NSNotification) {
    let contentInsets: UIEdgeInsets = UIEdgeInsetsZero
    scrollView.contentInset = contentInsets
}

func textFieldDidBeginEditing(textField: UITextField) {
    myTextField = textField
    scrollView.scrollEnabled = true
}

func textFieldDidEndEditing(textField: UITextField) {
    myTextField = nil
    scrollView.scrollEnabled = true
} 

I have tried implementing textViewDidBeginEditing and textViewDidEndEditing and then assigning that in place of myTextView in this line: let activeTextFieldRect: CGRect? = myTextField?.frame let activeTextFieldRect: CGRect? = myTextField?.frame but that seems like a sloppy way to do this and doesn't work anyway. Any help is much appreciated.

Answer 1

Step one is to determine the textfield or textview which is the current first responder. Either use both textField and textView delegates to correctly determine the first responder or iterate through all the text fields and text views to see which is the first responder by doing something like:

func activeItemRect() -> CGRect? {
        for textField in textFields {
            if textField.isFirstResponder() { return textField.frame }
        }
        for textView in textViews{
            if textView.isFirstResponder() { return textView.frame }
        }
        return nil
    }

Step two is to determine if the current item is in the visible portion of the view or not. This you are doing by checking whether the origin of selected item is inside the visible rect of the view. You should be checking the centre or bottom of the selected item instead of its origin because sometimes the origin will be within the visible view rect but hidden by the iOS text input suggestions panel which appears right on top of the keyboard.

Posting below the entire code I used to test your scenario:

class ViewController: UIViewController {

    @IBOutlet var textFields: [UITextField]!
    @IBOutlet var textViews: [UITextView]!
    @IBOutlet weak var scrollView: UIScrollView!

    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillShow:", name: UIKeyboardWillShowNotification, object: nil)
        NSNotificationCenter.defaultCenter().addObserver(self, selector: "keyboardWillHide:", name: UIKeyboardWillHideNotification, object: nil)
    }

    override func viewWillDisappear(animated: Bool) {
        super.viewWillDisappear(animated)
        NSNotificationCenter.defaultCenter().removeObserver(self)
    }


    override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
        for textField in textFields { textField.resignFirstResponder() }
        for textView in textViews{ textView.resignFirstResponder() }
    }

    func activeItemRect() -> CGRect? {
        for textField in textFields {
            if textField.isFirstResponder() { return textField.frame }
        }
        for textView in textViews{
            if textView.isFirstResponder() { return textView.frame }
        }
        return nil
    }

    func keyboardWillShow(sender: NSNotification) {
        let info: NSDictionary = sender.userInfo!
        let value: NSValue = info.valueForKey(UIKeyboardFrameBeginUserInfoKey) as! NSValue
        let keyboardSize: CGSize = value.CGRectValue().size
        let contentInsets: UIEdgeInsets = UIEdgeInsetsMake(0.0, 0.0, keyboardSize.height + 20, 0.0)
        scrollView.contentInset = contentInsets

        var aRect: CGRect = self.view.frame
        aRect.size.height -= keyboardSize.height
        let activeTextFieldRect: CGRect? = activeItemRect()
        let activeTextFieldCentre: CGPoint? = CGPointMake(CGRectGetMidX(activeTextFieldRect!), CGRectGetMidY(activeTextFieldRect!))
        if (!CGRectContainsPoint(aRect, activeTextFieldCentre!)) {
            scrollView.scrollRectToVisible(activeTextFieldRect!, animated:true)
        }
    }

    func keyboardWillHide(sender: NSNotification) {
        let contentInsets: UIEdgeInsets = UIEdgeInsetsZero
        scrollView.contentInset = contentInsets
    }

}

First I created an IBOutletCollection for all text fields. Then I created an IBoutletCollection for all text views. Then created method that will loop through all textFields and textViews and returns the frame of the active item.

Rest of the code is 90% similar to what you are doing. Only difference is instead of checking if the origin of selected item lies within visible portion of the view I am checking if the centre of selected item lies within the visible portion of the view.