我如何检测文本字段中的任何文本变化?委托方法shouldChangeCharactersInRange适用于某些东西,但它并没有完全满足我的需求。因为在它返回YES之前,textField文本对其他观察器方法是不可用的。

例如,在我的代码calculateAndUpdateTextFields没有得到更新的文本,用户已经键入。

是他们的任何方式得到类似textChanged Java事件处理程序。

- (BOOL)textField:(UITextField *)textField 
            shouldChangeCharactersInRange:(NSRange)range 
            replacementString:(NSString *)string 
{
    if (textField.tag == kTextFieldTagSubtotal 
        || textField.tag == kTextFieldTagSubtotalDecimal
        || textField.tag == kTextFieldTagShipping
        || textField.tag == kTextFieldTagShippingDecimal) 
    {
        [self calculateAndUpdateTextFields];

    }

    return YES;
}

当前回答

我解决了改变shouldChangeChractersInRange行为的问题。如果你返回NO,这些更改不会被iOS内部应用,相反,你有机会手动更改它,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
}

其他回答

Swift测试版本:

//Somewhere in your UIViewController, like viewDidLoad(){ ... }
self.textField.addTarget(
        self, 
        action: #selector(SearchViewController.textFieldDidChange(_:)),
        forControlEvents: UIControlEvents.EditingChanged
)

参数解释道:

self.textField //-> A UITextField defined somewhere in your UIViewController
self //-> UIViewController
.textFieldDidChange(_:) //-> Can be named anyway you like, as long as it is defined in your UIViewController

然后在你的UIViewController中添加你上面创建的方法:

//Gets called everytime the text changes in the textfield.
func textFieldDidChange(textField: UITextField){

    print("Text changed: " + textField.text!)

}

我解决了改变shouldChangeChractersInRange行为的问题。如果你返回NO,这些更改不会被iOS内部应用,相反,你有机会手动更改它,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
}

这里是相同的swift版本。

textField.addTarget(self, action: "textFieldDidChange:", forControlEvents: UIControlEvents.EditingChanged)

func textFieldDidChange(textField: UITextField) {

}

谢谢

Swift 3版本:

class SomeClass: UIViewController, UITextFieldDelegate { 

   @IBOutlet weak var aTextField: UITextField!


    override func viewDidLoad() {
        super.viewDidLoad()

        aTextField.delegate = self
        aTextField.addTarget(self, action: #selector(SignUpVC.textFieldDidChange), for: UIControlEvents.editingChanged)        
    }

   func textFieldDidChange(_ textField: UITextField) {

       //TEXT FIELD CHANGED..SECRET STUFF

   }

}

不要忘记设置委托。

Swift 3版本

yourTextField.addTarget(self, action: #selector(YourControllerName.textChanges(_:)), for: UIControlEvents.editingChanged)

把零钱放在这里

func textChanges(_ textField: UITextField) {
    let text = textField.text! // your desired text here
    // Now do whatever you want.
}

希望能有所帮助。