ios - 如何打开带有条件 IF 的新 View

Question

我想显示新的 ViewController，就在文本字段不为空或不相同时。当我单击将用户导航到下一个 View 的按钮时，总是执行此操作，即使不满足条件也是如此。

@IBAction func nextButtonPressed(_ sender: Any) {
    self.performSegue(withIdentifier: "goToLastRegisterView", sender: self)
}

override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
    if usernameTextField.text == "" || passwordTextField.text == "" || confirmedPasswordTextField.text == "" {
        errorLabel.isHidden = false
        errorLabel.text = "All fields are required"
    }
    else{
        if passwordTextField.text == confirmedPasswordTextField.text{
            if segue.identifier == "goToLastRegisterView"{
                let secondRegisterVC = segue.destination as! RegisterSecondViewController
                secondRegisterVC.userName = usernameTextField.text!
                secondRegisterVC.password = passwordTextField.text!

            }
        }
        else{
            errorLabel.isHidden = false
            errorLabel.text = "Different passwords"
        }
    }
}

Answer 1

如果您执行了 self.performSegue(withIdentifier: 来检查 override func prepare(for 中的 textfeilds 为时已晚，您必须在按钮操作中执行此操作

@IBAction func nextButtonPressed(_ sender: Any) {

    if usernameTextField.text == "" || passwordTextField.text == "" || confirmedPasswordTextField.text == "" {
        errorLabel.isHidden = false
        errorLabel.text = "All fields are required"
        return 
    }
    self.performSegue(withIdentifier: "goToLastRegisterView", sender: self)
}