问题
I need to increase a text field's width according to its content. When the user inputs text, then the textfield size should increase automatically. I have one close (X) button next to this text field.
I have constrained the text field and button so that the text field is centered on screen, and the button is adjacent to it. (Text field should be editable, button should be clickable)
Text field size is this:
When I enter text in it, the size should automatically increase:
How can I achieve this?
回答1:
You can achieve it with overriding UITextField class and return custom value in intrinsicContentSize. Also you need to subscribe to text change event and invalidate intrinsic content size on text change animated
Here is example in Swift 3
class Test: UITextField {
override init(frame: CGRect) {
super.init(frame: frame)
setupTextChangeNotification()
}
required init?(coder aDecoder: NSCoder) {
super.init(coder: aDecoder)
setupTextChangeNotification()
}
func setupTextChangeNotification() {
NotificationCenter.default.addObserver(
forName: Notification.Name.UITextFieldTextDidChange,
object: self,
queue: nil) { (notification) in
UIView.animate(withDuration: 0.05, animations: {
self.invalidateIntrinsicContentSize()
})
}
}
deinit {
NotificationCenter.default.removeObserver(self)
}
override var intrinsicContentSize: CGSize {
if isEditing {
if let text = text,
!text.isEmpty {
// Convert to NSString to use size(attributes:)
let string = text as NSString
// Calculate size for current text
var size = string.size(attributes: typingAttributes)
// Add margin to calculated size
size.width += 10
return size
} else {
// You can return some custom size in case of empty string
return super.intrinsicContentSize
}
} else {
return super.intrinsicContentSize
}
}
}
回答2:
I solve my problem : use this for textfield not go outside of screen.
func getWidth(text: String) -> CGFloat
{
let txtField = UITextField(frame: .zero)
txtField.text = text
txtField.sizeToFit()
return txtField.frame.size.width
}
func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool
{
let width = getWidth(textField.text!)
if UIScreen.mainScreen().bounds.width - 55 > width
{
txtWidthOfName.constant = 0.0
if width > txtWidthOfName.constant
{
txtWidthOfName.constant = width
}
self.view.layoutIfNeeded()
}
return true
}
Objective C Version
-(CGFloat)getWidth:(NSString *)text{
UITextField * textField = [[UITextField alloc]initWithFrame:CGRectZero];
textField.text = text;
[textField sizeToFit];
return textField.frame.size.width;
}
-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
if (self.textFieldName.isEditing == YES) {
CGFloat width = [self getWidth:textField.text];
if ([UIScreen mainScreen].bounds.size.width - 60 > width) {
self.txtWidthOfName.constant = 0.0;
if (width > self.txtWidthOfName.constant) {
self.txtWidthOfName.constant = width;
}
[self.view layoutIfNeeded];
}
}
return YES;
}
回答3:
A cheeky workaround to get width for a particular string would be
func getWidth(text: String) -> CGFloat {
let txtField = UITextField(frame: .zero)
txtField.text = text
txtField.sizeToFit()
return txtField.frame.size.width
}
And to get the width,
let width = getWidth(text: "Hello world")
txtField.frame.size.width = width
self.view.layoutIfNeeded() // if you use Auto layout
If you have a constraint linked to txtField's width then do
yourTxtFieldWidthConstraint.constant = width
self.view.layoutIfNeeded() // if you use Auto layout
Edit We are creating a UITextField with a frame of basically all zeros. When you call sizeToFit(), it will set the frame of UITextField in a way that it will show all of its content with literally no extra spaces around it. We only wanted its width, so I returned the width of the newly created UITextField. ARC will take care of removing it from memory for us.
Update
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
if textField.text != nil {
let text = textField.text! as NSString
let finalString = text.replacingCharacters(in: range, with: string)
textField.frame.size.width = getWidth(text: finalString)
}
return true
}
回答4:
Implement following method of UITextFieldDelegate. Use approach provided by Matt to get required width of textField. In auto layout make sure you have centre and width constraints set for textfield. Create IBOutlet for your width constraint in code file. Also make sure you set delegate property of your textField
@IBOutlet weak var widthConstraint: NSLayoutConstraint!
func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
let width = getWidth(text : textField.text)
if width > widthConstraint.constant {
widthConstraint.constant = width
}
self.layoutIfNeeded()
return true
}
回答5:
The answers all require a bunch of code, but you can do everything interface builder; no code needed.
Just embed the textField in a UIStackView and constrain the stackView to be less than or equal to its superview minus some constant (if you want you can also give it a minimum width). The stackView will take care of always making the textField its intrinsic size, or the maxwidth of the stackView (which ever is smaller), so as you type the size changes automatically to fit the content.
回答6:
I think this is a better solution than having a width constraint that you have to modify:
Resize a UITextField while typing (by using Autolayout)
- (IBAction) textFieldDidChange: (UITextField*) textField
{
[UIView animateWithDuration:0.1 animations:^{
[textField invalidateIntrinsicContentSize];
}];
}
You can omit the animation if desired..
EDIT: Here's an example project: https://github.com/TomSwift/growingTextField
回答7:
We can easily make it by setting UITextField constraints like this:
//Tested on Xcode 9.1, Swift 4
Output:
回答8:
Seems so frustrating that there is no direct way like there is "Autoshrink" to "Minimum Font size" for UILabel in IB itself.
The "Adjust to Fit" in IB for a textfield is no good too.
Why does Apple make us write all this boilerplate code, when a text field needs Autoshrink as much if not more than the UILabel!
来源：https://stackoverflow.com/questions/41436716/how-to-increase-width-of-textfield-according-to-typed-text