UITextField值更改事件？

Question

如何才能使文本字段的内容发生变化时，会调用一个函数？

Answer 1

<强>目标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

我解决了改变shouldChangeChractersInRange行为的问题。如果您返回NO，iOS内部将不会应用更改，您可以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

对于swift来说这很方便 -

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

Answer 5

这是我的解决方法。

快捷键4

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

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