UITextField

今天介紹其他 TextField 其他常見的用法

字數限制

func textField(_ textField: UITextField, shoudChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    guard let text = textField.text else { return }
    let count = text.count + string.count - range.length
    return count <= 10
}

return count <= 限制字數

自動換行

新增 TextField ，並在 viewDidLoad 幫每個 TextField 增加 tag

@IBOutlet weak var firstTextField: UITextField!
@IBOutlet weak var secondTextFIeld: UITextField!
@IBOutlet weak var thirdTextField: UITextField!
@IBOutlet weak var fourthTextField: UITextField!
@IBOutlet weak var fifthTextField: UITextField!

    override func viewDidLoad() {
        super.viewDidLoad()
        
        firstTextField.tag = 0
        secondTextFIeld.tag = 1
        thirdTextField.tag = 2
        fourthTextField.tag = 3
        fifthTextField.tag = 4
        
        delegateAndDataSourseInit()
    }
    
    func delegateAndDataSourseInit() {
        firstTextField.delegate = self
        secondTextFIeld.delegate = self
        thirdTextField.delegate = self
        fourthTextField.delegate = self
        fifthTextField.delegate = self
    }

接著在 textFieldShouldReturn 的 Function 內加入以下程式碼

let nextTag = textField.tag + 1

if let nextResponder = textField.superview?.viewWithTag(nextTag) {
    nextResponder.becomeFirstResponder()
} else {
    textField.resignFirstResponder()
    textField.endEditing(true)
}

這樣一來， TextField 就會在使用者按下 enter 鍵之後自動跳下一行了。