问题描述
Am在Xamarin Android上实现了系统计时器,当倒计时结束时,我遇到了一个已发生事件,即未引发带有消息“ Time up up”的对话框的问题... 我认为问题可能不是在用户界面线程上实现的,所以我需要您的帮助来实现这一目标... 这是我的计时器代码
class SecondActivity : AppCompatActivity
{
int counter = 10;
private System.Timers.Timer _timer;
private int _countSeconds;
protected override void OnCreate(Bundle savedInstanceState)
{
_timer = new System.Timers.Timer();
//Trigger event every second
_timer.Interval = 1000;
_timer.Elapsed += OnTimedEvent;
//count down 5 seconds
_timer.Enabled = true;
_countSeconds = 5;
}
private void OnTimedEvent(object sender,System.Timers.ElapsedEventArgs e)
{
_countSeconds--;
if (_countSeconds == 0) {
_timer.Stop();
Switch switch1 = this.FindViewById<Switch>(Resource.Id.switch2);
Android.App.AlertDialog.Builder dialog = new Android.App.AlertDialog.Builder(this);
Android.App.AlertDialog alert = dialog.Create();
alert.SetTitle("");
alert.SetMessage("Simple Alert");
alert.SetButton("OK",(c,ev) =>
{
// Ok button click task
});
switch1.Checked = false;
}
我只希望Elapsed事件处理程序在变量倒计数等于0时显示一个警告对话框,谢谢
解决方法
在第一条评论向我提出一个相关问题之后,我找到了实现用户线程的方法,现在它可以按预期的方式显示警报对话框...
private void OnTimedEvent(object sender,System.Timers.ElapsedEventArgs e)
{
//This is how to make the Timer callback on the UI
RunOnUiThread(() =>
{
_countSeconds--;
if (_countSeconds == 0)
{
Switch switch1 = this.FindViewById<Switch>(Resource.Id.switch2);
Android.App.AlertDialog.Builder dialog = new Android.App.AlertDialog.Builder(this);
Android.App.AlertDialog alert = dialog.Create();
alert.SetTitle("Its over");
alert.SetMessage("Simple Alert");
alert.SetButton("OK",(c,ev) =>
{
// Ok button click task
});
alert.Show();
switch1.Checked = true;
}
});
}