使用长轮询更新Google地图标记，而不会阻止UI

I have a Google Map (MapFragment) with more than 5 markers on it. I want to update the position of markers for every 10-15 seconds. I will be getting new co ordinates via a API call.

我有一个谷歌地图(MapFragment),上面有超过5个标记。我想每10-15秒更新一次标记的位置。我将通过API调用获得新的坐标。

Is there any way we can update the markers without blocking the UI? Sample C# snippet for long polling would be awesome..

有没有什么方法可以在不阻止UI的情况下更新标记?用于长轮询的示例C#片段会很棒..

I tried doing -

我试过 -

    RunOnUiThread(() =>
    {
        while(true){
          //UPDATE MARKERS HERE
          Thread.Sleep(5000);
        }
    }

but it freeze the UI. Is there any way to update markers without freezing UI?

但它冻结了UI。有没有办法更新标记而不冻结UI?

1 个解决方案

#1

Doing:

RunOnUiThread(() =>
{
    while(true){
      //UPDATE MARKERS HERE
      Thread.Sleep(5000);
    }
}

Forces everything inside of the anonymous method to run on the UI thread. So the while loop inclusive of the Thread.Sleep is blocking the UI.

强制匿名方法内的所有内容在UI线程上运行。因此包含Thread.Sleep的while循环阻止了UI。

Instead you want to do your long operation asynchronously, for instance using TPL (async/await) in C#.

相反,您希望异步执行长时间操作,例如在C#中使用TPL(async / await)。

Dictionary<int, Marker> _markers = new Dictionary<int, Marker>();

async Task PollServerAsync(CancellationToken cancellationToken)
{
    while (!cancellationToken.IsCancellationRequested)
    {
        var coordinates = await GetNewCoordinatesFromServerAsync(cancellationToken);

        foreach (var coord in coordinates)
        {
            var marker = _markers[_coord.Id];
            RunOnUiThread(() =>
            {
                marker.SetPosition(coord.Position);    
            });
        }

        await Task.Delay(5000, cancellationToken);
    }
}

#1