Question

我的Xamarin iOS应用程序出现线程/睡眠问题。我想创造一个简单的游戏，一种记忆游戏。按下开始按钮时，将有4个按钮可以更改字体。从1开始，然后是2，依此类推。问题是我希望在显示按钮的方法中暂停一下，因为用户需要看几秒钟后更改的颜色。我认为多线程直接赶上下一个任务，所以睡眠消失了:(如何解决这个问题？谢谢！

代码：

    partial void btnStart (NSObject sender)
    {
        teller++;

        InvokeOnMainThread( ()=> { for (int i = 0; i < teller; i++) {
                String randomGetal = randomizer();
                Lijst.Add(new Opslag() {nummerGetal = teller, getal = randomGetal});
                ThreadPool.QueueUserWorkItem(o => InvokeOnMainThread(() => {ButtonColor(randomGetal);}));
        };
        });
        lblRandom1.Text = Lijst.Count.ToString();
    }

    public void ClearButton()
    {
        btnA.SetTitleColor (UIColor.Green, UIControlState.Normal);
        btnB.SetTitleColor (UIColor.Green, UIControlState.Normal);
        btnC.SetTitleColor (UIColor.Green, UIControlState.Normal);
        btnD.SetTitleColor (UIColor.Green, UIControlState.Normal);
    }

    public void ButtonColor(string a)
    {

        if (a == "A") {
            btnA.SetTitleColor (UIColor.Magenta, UIControlState.Normal);
            Thread.Sleep(2000);
            ClearButton ();
        }

        if (a == "B") {
            btnB.SetTitleColor (UIColor.Magenta, UIControlState.Normal);
            Thread.Sleep(2000);
            ClearButton ();
        }

        if (a == "C") {
            btnC.SetTitleColor (UIColor.Magenta, UIControlState.Normal);
            Thread.Sleep(2000);
            ClearButton ();
        }

        if (a == "D") {
            btnD.SetTitleColor (UIColor.Magenta, UIControlState.Normal);
            Thread.Sleep(2000);
            ClearButton ();
        }
    }

    public string randomizer()
    {
        int randomNummer = random.Next (0, 4);
        if (randomNummer == 0)
            return "A";
        if (randomNummer == 1)
            return "B";
        if (randomNummer == 2)
            return "C";
        if (randomNummer == 3)
            return "D";
        else
            return "Empty";
    }

}

public class Opslag
{
    public int nummerGetal {get;set;        
    }

    public string getal {
        get;
        set;
    }

}

}

Answer 1

我和Xamarin Android有类似的问题。 Thread.Sleep（）不起作用：
- 都不是来自System.Threading.Thread.Sleep()
- 也不是Java.Lang.Thread.Sleep()

花了2小时试图解决问题发现above answer，但有点复杂，决定提炼核心问题。

<强>解决方案

替换'基于线程'的睡眠，就像这里：

DoSth() {
  Thread newThread = new Thread(new ThreadStart(DoWork));
  newThread.Start();
}

void DoWork() {
  Thread.Sleep(5000);
  // do sth after 5 secs
}

使用'基于异步的'方法：

DoSth() {
  DoWorkAsync();
}

async void DoWorkAsync() {
  await Task.Delay(5000);
  // do sth after 5 secs
}

顺便说一句。只有在应用程序启动后非常小的问题才会出现问题。

Answer 2

我知道你可以使用它，但这是一个简化代码的快速建议：

    private UIButton[] buttons;
    private Random random;

    public override void ViewDidLoad()
    {
        base.ViewDidLoad ();

        this.buttons = new [] { btnA, btnB, btnC, btnD };

        this.random = new Random ();

        // put in an event handler to fire up ButtonColor
    }

    private async void ButtonColor()
    {
        var r = random.Next (0, this.buttons.Length);
        if (r < this.buttons.Length)
        {
            var button = this.buttons [r];
            var curColor = button.TitleColor(UIControlState.Normal);
            button.SetTitleColor(UIColor.Magenta, UIControlState.Normal);
            await Task.Delay (2000);
            button.SetTitleColor(curColor, UIControlState.Normal);
        }
    }

Xamarin iOS Sleep UI线程无效

2 个答案: