UITextField 值更改事件？

Question

如何才能在文本字段的内容发生更改时调用函数？

Answer 1

Objective-C

[myTextField addTarget:self 
                action:@selector(textFieldDidChange:) 
      forControlEvents:UIControlEventEditingChanged];

Swift 4

myTextField.addTarget(self, action: #selector(textFieldDidChange(sender:)), for: .editingChanged)

@objc func textFieldDidChange(sender: UITextField) {...}

Answer 2

实际上，UITextField 没有值更改事件，请使用 UIControlEventEditingChanged

Answer 3

我解决了更改 shouldChangeChractersInRange 行为的问题。如果您返回“否”，则 iOS 不会在内部应用更改，而是您有机会手动更改它并在更改后执行任何操作。

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    //Replace the string manually in the textbox
    textField.text = [textField.text stringByReplacingCharactersInRange:range withString:string];
    //perform any logic here now that you are sure the textbox text has changed
    [self didChangeTextInTextField:textField];
    return NO; //this make iOS not to perform any action
}

Answer 4

这是我的解决方案。

斯威夫特4

textField.addTarget(self, action: #selector(self.textFieldDidChange(sender:)), for: .editingChanged)

@objc func textFieldDidChange(sender: UITextField){
   print("textFieldDidChange is called")
}

Answer 5

对于 swift 来说这很方便 -

textField.addTarget(self, action: #selector(onTextChange), forControlEvents: UIControlEvents.EditingChanged)