Toast 通知不适用于 JavaScript 呼叫

Question

我正在使用 Xamarin.Android 开发应用程序，我想在从 JavaScript 导出报告时显示 Toast 通知。我的应用调用报告并成功生成。但是，从不显示 Toast 通知。我发现只有当我在该特定行中设置断点时，它才会显示在 Visual Studio 2017.

这是我的 C# class 处理 JS 的一部分。

class CallJSInterface : Java.Lang.Object
{
    private class Timetable
    {
        public string member { get; set; }
        public string role { get; set; }
        public string time { get; set; }
        public string lastColor { get; set; }
    }

    private Context context;
    public CallJSInterface(Context context)
    {
        this.context = context;
    }

    [Export]
    [JavascriptInterface]
    public void ExportToExcel(string results)
    {
        Toast.MakeText(context, context.GetString(Resource.String.LblExportMsg), ToastLength.Short).Show();

        var timetable = JsonConvert.DeserializeObject<List<Timetable>>(results);

        //Excel conversion
    }
}

这是 LblExportMsg 在 Strings.xml:

中的值

<string name="LblExportMsg">Exporting your Agenda to Excel.</string>

另外，这是我在JS中调用函数的例子：

$("#linkDownload").click(function (e) {
    e.preventDefault();
    CSharp.ExportToExcel('[{"member":"Luis","role":"Timer","time":"00:15:15","lastColor":"red"},{"member":"Luis","role":"Timer 1","time":"00:15:00","lastColor":"green"},{"member":"Luis","role":"Timer 2","time":"00:15:17","lastColor":"red"},{"member":"Luis","role":"Timer 3","time":"00:07:15","lastColor":"green"},{"member":"Luis","role":"Timer 4","time":"00:23:15","lastColor":"red"},{"member":"Luis","role":"Timer 5","time":"00:15:15","lastColor":"green"},{"member":"Luis","role":"Timer 6","time":"01:15:15","lastColor":"yellow"},{"member":"Luis","role":"Timer 7","time":"00:18:15","lastColor":"green"},{"member":"Luis","role":"Timer 8","time":"00:15:22","lastColor":"green"}]');
});

此外，HTML 按钮：

<button type="button" id="linkDownload">Export</button>

最后，这就是我将 JS 界面从主视图添加到 WebView 的方式 activity:

webView.AddJavascriptInterface(new CallJSInterface(this), "CSharp");

有谁知道我做错了什么？它与上下文有关吗？我怎样才能检查它？感谢您的帮助。

PS:

最低 SDK 为 21，目标 SDK 27。
我正在使用 JSON.NET 进行反序列化。

Answer 1

我能够修复它，我在导出报告之前添加了一个超时，并且将过程一分为二，一个用于显示 Toast，另一个用于报告。

$("#linkDownload").click(function (e) {
    CSharp.Alert(currentTranslation.lblExportMsg);
    setTimeout(function () {
        CSharp.ExportToExcel(JSON.stringify(results));
    }, 250);
});

Toast 通知不适用于 JavaScript 呼叫

Toast notifications are not working on a JavaScript call

javascript

c#

android

xamarin.android

android-toast