ios - 以编程方式在 UIView 上添加 UITextField Swift

Question

我是 Swift 和 iOS 编程的新手。我试图使用 Swift 以编程方式创建一个 UITextField 但无法完全正确。另外，如何将其更改为具有淡入背景的半透明效果？

var myField: UITextField = UITextField (frame:CGRectMake(10, 10, 30, 10));
self.addSubview(myField)

Answer 1

Swift 3 和 Swift 4.2:

override func viewDidLoad() {
    super.viewDidLoad()

    let sampleTextField =  UITextField(frame: CGRect(x: 20, y: 100, width: 300, height: 40))
    sampleTextField.placeholder = "Enter text here"
    sampleTextField.font = UIFont.systemFont(ofSize: 15)
    sampleTextField.borderStyle = UITextField.BorderStyle.roundedRect
    sampleTextField.autocorrectionType = UITextAutocorrectionType.no
    sampleTextField.keyboardType = UIKeyboardType.default
    sampleTextField.returnKeyType = UIReturnKeyType.done
    sampleTextField.clearButtonMode = UITextField.ViewMode.whileEditing
    sampleTextField.contentVerticalAlignment = UIControl.ContentVerticalAlignment.center
    sampleTextField.delegate = self
    self.view.addSubview(sampleTextField)
}

委托(delegate)方法:

// MARK:- ---> UITextFieldDelegate

extension ViewController: UITextFieldDelegate {

    func textFieldShouldBeginEditing(_ textField: UITextField) -> Bool {
        // return NO to disallow editing.
        print("TextField should begin editing method called")
        return true
    }

    func textFieldDidBeginEditing(_ textField: UITextField) {
        // became first responder
        print("TextField did begin editing method called")
    }

    func textFieldShouldEndEditing(_ textField: UITextField) -> Bool {
        // return YES to allow editing to stop and to resign first responder status. NO to disallow the editing session to end
        print("TextField should snd editing method called")
        return true
    }

    func textFieldDidEndEditing(_ textField: UITextField) {
        // may be called if forced even if shouldEndEditing returns NO (e.g. view removed from window) or endEditing:YES called
        print("TextField did end editing method called")
    }

    func textFieldDidEndEditing(_ textField: UITextField, reason: UITextFieldDidEndEditingReason) {
        // if implemented, called in place of textFieldDidEndEditing:
        print("TextField did end editing with reason method called")
    }

    func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
        // return NO to not change text
        print("While entering the characters this method gets called")
        return true
    }

    func textFieldShouldClear(_ textField: UITextField) -> Bool {
        // called when clear button pressed. return NO to ignore (no notifications)
        print("TextField should clear method called")
        return true
    }

    func textFieldShouldReturn(_ textField: UITextField) -> Bool {
        // called when 'return' key pressed. return NO to ignore.
        print("TextField should return method called")
        // may be useful: textField.resignFirstResponder()
        return true
    }

}

// MARK: UITextFieldDelegate <---

---

swift 2.0:

let sampleTextField = UITextField(frame: CGRectMake(20, 100, 300, 40))
sampleTextField.placeholder = "Enter text here"
sampleTextField.font = UIFont.systemFontOfSize(15)
sampleTextField.borderStyle = UITextBorderStyle.RoundedRect
sampleTextField.autocorrectionType = UITextAutocorrectionType.No
sampleTextField.keyboardType = UIKeyboardType.Default
sampleTextField.returnKeyType = UIReturnKeyType.Done
sampleTextField.clearButtonMode = UITextFieldViewMode.WhileEditing;
sampleTextField.contentVerticalAlignment = UIControlContentVerticalAlignment.Center
sampleTextField.delegate = self
self.view.addSubview(sampleTextField)

委托(delegate)方法:

    // MARK:- ---> Textfield Delegates
    func textFieldDidBeginEditing(textField: UITextField) {
        print("TextField did begin editing method called")
    }

    func textFieldDidEndEditing(textField: UITextField) {
        print("TextField did end editing method called")
    }

    func textFieldShouldBeginEditing(textField: UITextField) -> Bool {
        print("TextField should begin editing method called")
        return true;
    }

    func textFieldShouldClear(textField: UITextField) -> Bool {
        print("TextField should clear method called")
        return true;
    }

    func textFieldShouldEndEditing(textField: UITextField) -> Bool {
        print("TextField should snd editing method called")
        return true;
    }

    func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {
        print("While entering the characters this method gets called")
        return true;
    }

    func textFieldShouldReturn(textField: UITextField) -> Bool {
        print("TextField should return method called")
        textField.resignFirstResponder();
        return true;
    }
    // MARK: Textfield Delegates <---