Question

我希望AlertDialog的消息“1”出现在屏幕上，3秒后消失，然后我想要另一个警告消息，消息“2”出现在屏幕上，3秒后消失，依此类推，直到5。我有以下代码：

[Activity(Label = "TestAlertDialogBuilder", MainLauncher = true)]
public class MainActivity : Activity
{
    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.Main);

        for (int i=0; i <=5 ; i++)
        {
            //making the program stop so I can see the alert showing and dissappearing
            System.Threading.Thread.Sleep(3000);
            ShowAlert(i);
        }
    }

    Dialog dialog;
    public void ShowAlert(int i)
    {
        if (dialog != null)
        {
            dialog.Cancel();
        }
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);
        alertDialog.SetMessage(i.ToString());
        dialog = alertDialog.Create();
        dialog.Show();
    }
}

但是在程序执行一段时间之后，我只得到一个带有消息“5”的AlertDialog，就是这样。如果有人认为我的问题的另一个标题更合适，他可以改变它。

Answer 1

转换Mohamed Mohaideen AH对C＃语言的回答。

public class MyRunnable : Java.Lang.Object, Java.Lang.IRunnable
{
    private MainActivity mainActivity;

    public MyRunnable(MainActivity mainActivity)
    {
        this.mainActivity = mainActivity;
    }

    public void Run()
    {
        for (int i = 0; i <= 5; i++)
        {
            try
            {
                Java.Lang.Thread.Sleep(3000);
            }
            catch (Java.Lang.Exception e)
            {
                e.PrintStackTrace();
            }
            mainActivity.RunOnUiThread(() =>
            {
                mainActivity.ShowAlert(i);
            });
        }
    }
}


[Activity(Label = "App5", MainLauncher = true)]
public class MainActivity : Activity
{

    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        // Set our view from the "main" layout resource
        SetContentView(Resource.Layout.Main);


        MyRunnable myRunnable = new MyRunnable(this);
        Java.Lang.Thread thread = new Java.Lang.Thread(myRunnable);
        thread.Start();

    }
    Dialog dialog;
    public void ShowAlert(int i)
    {
        if (dialog != null)
        {
            dialog.Cancel();
        }
        AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);

        alertDialog.SetMessage("AlertDialog: " + i);
        dialog = alertDialog.Create();
        dialog.Show();
    }
}

Answer 2

由于阻止UI主线程直到执行循环而发生问题。因此，为对话框创建单独的线程＆amp;在UI中显示它。

试试这个

Thread thread = new Thread(new Runnable() {

        int i = 0;
        @Override
        public void run() {
            for (i=0; i <=5 ; i++)
            {
                //making the program stop so I can see the alert showing and dissappearing
                try {
                    Thread.sleep(3000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        ShowAlert(i);
                    }
                });

            }

        }
    });
   thread.start();

 public void ShowAlert(int i)
{
    if (dialog != null)
    {
        dialog.cancel();
    }
    AlertDialog.Builder alertDialog = new AlertDialog.Builder(this);

    alertDialog.setMessage("" + i);
    dialog = alertDialog.create();
    dialog.show();
}

如何使AlertDialogs连续出现和消失？

2 个答案: