Xamarin PCL：在Android上隐藏软键盘（Dependecy Service）不起作用

Question

我触发条目的onfocus代码，但Android中的隐藏代码并不隐藏软键盘。

接口

public interface IKeyboardService
{
    void Hide();
    void Show();
}

视图模型

public void OnFocused()
{
   var serv = DependencyService.Get<IKeyboardService>();

   if (cp.FindByName<SwitchCell>("SCell").On)
   {
      serv.Show();
   }
   else
   {
      serv.Hide();
   }
}

Android代码

[assembly: Dependency(typeof(KeyboardService))]
namespace KeyboardHide.Droid.DependencyServices
{
    public class KeyboardService : IKeyboardService
    {
        public void Hide()
        {
            var inputMethodManager = Xamarin.Forms.Forms.Context.GetSystemService(Context.InputMethodService) as InputMethodManager;
            if (inputMethodManager != null && Xamarin.Forms.Forms.Context is Activity)
            {
                var activity = Xamarin.Forms.Forms.Context as Activity;
                var focusedView = activity.CurrentFocus;
                var token = focusedView == null ? null : focusedView.WindowToken;
                inputMethodManager.HideSoftInputFromInputMethod(token, HideSoftInputFlags.None);
            }
        }

        public void Show()
        {

        }
    }
}

我也试过这段代码

码

var inputMethodManager = Xamarin.Forms.Forms.Context.GetSystemService(Context.InputMethodService) as InputMethodManager;
if (inputMethodManager != null && Xamarin.Forms.Forms.Context is Activity)
{
    var activity = Xamarin.Forms.Forms.Context as Activity;
    var focusedView = activity.CurrentFocus;
    var token = focusedView == null ? null : focusedView.WindowToken;
    inputMethodManager.ToggleSoftInputFromWindow(token, ShowSoftInputFlags.None, HideSoftInputFlags.None);
}

这对我来说是另一个项目吗？

*编辑：

以前的项目（为我的另一个项目工作）：

var inputMethodManager = Xamarin.Forms.Forms.Context.GetSystemService(Context.InputMethodService) as InputMethodManager;
if (inputMethodManager != null && Xamarin.Forms.Forms.Context is Activity)
{
    var activity = Xamarin.Forms.Forms.Context as Activity;
    var focusedView = activity.CurrentFocus;
    var token = focusedView == null ? null : focusedView.WindowToken;
    inputMethodManager.ToggleSoftInputFromWindow(token, ShowSoftInputFlags.None, HideSoftInputFlags.None);
}

但是对于我的新项目，它并不起作用。我仍然看到键盘，它并没有隐藏它，我也试过了：

Device.BeginInvokeOnMainThread(() => serv.Hide());

Answer 1

以下Android代码适用于我（从其他人那里获取此代码但不记得现在在哪里，我假设Xamarin论坛）。它具有能够被await编辑的附加好处，但如果您不想这样做，则可以删除TaskCompletionSource内容：

public Task<bool> DismissKeyboardAsync() {
    TaskCompletionSource<bool> result = new TaskCompletionSource<bool>();
    try {
        View view = ((MainActivity)Forms.Context).CurrentFocus;

        IBinder windowToken = view?.WindowToken;

        if(windowToken != null) {
            ((InputMethodManager)Forms.Context.GetSystemService(Context.InputMethodService)).HideSoftInputFromWindow(windowToken, HideSoftInputFlags.None);
            result.TrySetResult(true);
            return result.Task;
        }

        result.TrySetResult(false);
    } catch(System.Exception exception) {
        System.Console.WriteLine("\nIn NativeHelper_Android.DismissKeyboardAsync() - Exception:\n{0}\n", exception);
        result.TrySetException(exception);
        result.TrySetResult(false);
    }

    return result.Task;
}

没有async的示例可能是（这是未经测试的代码）：

public void Hide() {
    try {
        View view = ((MainActivity)Forms.Context).CurrentFocus;

        IBinder windowToken = view?.WindowToken;

        if(windowToken != null) {
            ((InputMethodManager)Forms.Context.GetSystemService(Context.InputMethodService)).HideSoftInputFromWindow(windowToken, HideSoftInputFlags.None);
        }
    } catch(System.Exception exception) {
        System.Console.WriteLine("\nIn NativeHelper_Android.DismissKeyboardAsync() - Exception:\n{0}\n", exception);
    }
}