如何在 xamarin.forms 中处理键盘 appearance/disappearance

Question

我有一个最上面的网格

<Grid.RowDefinitions>
<RowDefinition Height="*"/>
<RowDefinition Height="120"/>
<RowDefinition Height="1"/>
<RowDefinition Height="5"/>
<RowDefinition Height="35"/>
<RowDefinition Height="5"/>
</Grid.RowDefinitions>

在我的页面中。我怎么能有 * 行来调整它的高度以尊重屏幕键盘的存在或不存在？使第 0 行的内容随着键盘的出现而缩小。或者，至少我怎么能检测到键盘出现在编辑器上？我已经为该编辑器创建了一个自定义渲染器因此可以快速填充额外的平台特定代码。

Answer 1

您只能手动控制 Grid 行大小。 Editor.Focused 和 Editor.Unfocused 就是您要查找的内容。

但您可以将其与事件触发器结合使用(http://developer.xamarin.com/guides/cross-platform/xamarin-forms/working-with/triggers/):

<EventTrigger Event="Focused">
    <local:FocusedTriggerAction />
</EventTrigger>

public class FocusedTriggerAction : TriggerAction<Editor>
{
    protected override void Invoke (Editor editor)
    {
        yourRow.Height = new GridLength(100);
    }
}

Answer 2

目前我已经采用了此处找到的解决方案 http://www.gooorack.com/2013/08/28/xamarin-moving-the-view-on-keyboard-show/

    private UIView activeview;             // Controller that activated the keyboard

    /// <summary>
    /// Initializes a new instance of the <see cref="ExtendedEditorRenderer"/> class.
    /// </summary>
    public ExtendedEditorRenderer ()
    {
        NSNotificationCenter.DefaultCenter.AddObserver(UIKeyboard.DidShowNotification,KeyBoardUpNotification);
        NSNotificationCenter.DefaultCenter.AddObserver(UIKeyboard.WillHideNotification,KeyBoardDownNotification);
    }

    public void Dispose()
    {
        NSNotificationCenter.DefaultCenter.RemoveObserver(UIKeyboard.DidShowNotification);
        NSNotificationCenter.DefaultCenter.RemoveObserver(UIKeyboard.WillHideNotification);
        base.Dispose();
    }
    private void KeyBoardDownNotification(NSNotification notification)
    {
        try
        {
            var view = (ExtendedEditor)Element;
            if (view.KeyboardListener != null)
            {
                Size s = new Size(0, 0);
                view.KeyboardListener.keyboardSizeChangedTo(s);
            }
        }
        catch (Exception ex)
        {
            //Debug.WriteLine("dcaught {0}", ex);
        }
    }

    private void KeyBoardUpNotification(NSNotification notification)
    {
        try
        {
            // get the keyboard size
            CGRect r = UIKeyboard.BoundsFromNotification(notification);
            Size s = new Size(r.Size.Width, r.Size.Height);
            var v = (ExtendedEditor)Element;
            v.KeyboardListener.keyboardSizeChangedTo(s);
        }
        catch(Exception ex) {
            //Debug.WriteLine("scaught {0}", ex);
        }
    }

共享平台"independent"代码：

public interface IKeyboardListener
{
    void keyboardSizeChangedTo(Size s);
}

public class ExtendedEditor : Editor ...
{

如何在 xamarin.forms 中处理键盘 appearance/disappearance

How to I handle keyboard appearance/disappearance in xamarin.forms

xamarin.forms