UIAlertController错误

Question

我从我的添加栏按钮项目中调用下面的代码，其中我提出要求用户输入的警报视图。它第一次正常工作，并在之后给出以下错误：

代码：

var alert = UIAlertController(title: "Enter Blog Link", message: nil, preferredStyle: .Alert)
    func userBlogLinkEntryPopover() {
        //        let alert = UIAlertView(title: "Enter Blog Link", message: nil, delegate: self, cancelButtonTitle: "Cancel")
        alert.addTextFieldWithConfigurationHandler { (textField) -> Void in
            textField.placeholder = "Enter Blog URL!"
        }
        alert.addAction(UIAlertAction(title: "Ok", style: .Default, handler: { (action) -> Void in
            if let tf = self.alert.textFields?.first as? UITextField{
                println(tf.text)
            }
        }))
        alert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: nil))
        presentViewController(alert, animated: true, completion: nil)

    }

  

错误：＆＃39; UIAlertController只能有一个样式的动作   UIAlertActionStyleCancel＆＃39;

我认为每次按下添加按钮时都会尝试添加操作，因此错误。如果我错了请纠正我，还请建议解决。

感谢您的帮助。

Answer 1

如果你这样做，你也会得到这个，仔细阅读看看你是否能看到错误

    resendAlert.addAction(UIAlertAction(title: "Cancel", style: .cancel, handler: { (action: UIAlertAction!) in
        //cancel clicked
        return
    }))

    resendAlert.addAction(UIAlertAction(title: "Check Server", style: .cancel, handler: { (action: UIAlertAction!) in
        //check server clicked
        return
    }))

请注意---＆GT; .cancel 不使用TWICE需要.default才能使用 resendAlert.addAction(UIAlertAction(title: "Check Server", style: .default, handler: { (action: UIAlertAction!) in //check server clicked return }))

import java.awt.*;
import java.awt.event.*;
import javax.swing.Timer;

    public class Game2v4 extends Frame implements ActionListener, KeyListener
    {
        int x = 100;
        int y = 100;
        Timer myTimer = new Timer(10,this);


            Panel southPanel = new Panel();
                Button startButton = new Button("Start");
                Button clearButton = new Button("Clear");

        public Game2v4()
        {
            addKeyListener(this);
            setFocusable(true);
            this.setLayout(new BorderLayout());
                southPanel.setLayout(new GridLayout(1,2));
                    add(southPanel, BorderLayout.SOUTH);
                        southPanel.add(startButton);
                            startButton.addActionListener(this);
                        southPanel.add(clearButton);
                            clearButton.addActionListener(this);
addWindowListener
(
    new WindowAdapter()
    {
        public void windowClosing(WindowEvent e)
        {
            System.exit(0);
        }
    }
);
        }

        public void keyPressed(KeyEvent e)
        {
            if(e.getKeyCode() == KeyEvent.VK_UP)
            {
                y = y - 5;
                repaint();
            }

            if (e.getKeyCode() == KeyEvent.VK_DOWN)
            {
                y = y + 5;
                repaint();
            }

            if (e.getKeyCode() == KeyEvent.VK_RIGHT)
            {
                x = x + 5;
                repaint();
            }

            if (e.getKeyCode() == KeyEvent.VK_LEFT)
            {
                x = x - 5;
                repaint();
            }

                while(x >= 400)
                {
                    x = 1;
                    repaint();
                }

                while(x <= -10)
                {
                    x = 400;
                    repaint();
                }

                while(y >= 400)
                {
                    y = 1;
                    repaint();
                }

                while(y <= 0)
                {
                    y = 400;
                    repaint();
                }


        }

        public void keyReleased(KeyEvent e)
        {

        }

        public void keyTyped(KeyEvent e)
        {

        }

        public void actionPerformed(ActionEvent e)
        {
            Graphics g = getGraphics();
                if(e.getSource() == startButton)
                {
                    for(int i=250; i>0; i-=5)
                    {
                        g.drawRect(i,300,25,25);

                    }

                }
            this.requestFocus();
        }

        public void paint(Graphics g)
        {
            g.drawRect(x,y,25,25);
        }

        public static void main(String[] args)
        {
            Game2v4 f = new Game2v4();
                f.setBounds(50,100,400,400);
                f.setTitle("Gamev4");
                f.setVisible(true);
        }
    }

工作正常

Answer 2

我发现因为警报是在函数之外声明的，所以它保留了所有操作，并因此引发了异常。我更正了我的代码如下，它工作正常。

 func userBlogLinkEntryPopover() {       
        var alert = UIAlertController(title: "Enter Blog Link", message: nil, preferredStyle: .Alert)
        alert.addTextFieldWithConfigurationHandler { (textField) -> Void in
            textField.placeholder = "Enter Blog URL!"
        }
        alert.addAction(UIAlertAction(title: "Ok", style: .Default, handler: { (action) -> Void in
            if let tf = alert.textFields?.first as? UITextField{
                println(tf.text)
            }
        }))
        alert.addAction(UIAlertAction(title: "Cancel", style: .Cancel, handler: nil))
        presentViewController(alert, animated: true, completion: nil)

    }

此致

Answer 3

这就是让我绊倒的原因-自动填充错误。使用ObjC，而不是在操作上使用样式UIAlertActionStyleDefault，而是使用UIAlertControllerStyleAlert常量。没有警告，但是这两个都解析为枚举值1，因此我无意中向同一个控制器添加了两个Cancel操作。