cocoa - 如何在 Xamarin.Mac 中检测 NSView 的调整大小？

Question

检测 NSView 大小何时调整的正确方法是什么？ 我没有看到 View 上有任何可用的调整大小事件或 View 的任何委托(delegate)。

我添加了这个技巧，我使用drawRect来检测大小的变化，但我确信一定有一个更正确的方法来做到这一点。

    CGRect m_resizeRect = CGRect.Empty;
    public override void DrawRect(CGRect dirtyRect)
    {
        base.DrawRect(dirtyRect);
        if (this.InLiveResize) {
            if (m_resizeRect.Size != this.Bounds.Size) {
                m_resizeRect = this.Bounds;
                this.OnResize();
            }
        }
    }
    public override void ViewWillStartLiveResize()
    {
        m_resizeRect = this.Bounds;
        base.ViewWillStartLiveResize();
    }
    public override void ViewDidEndLiveResize()
    {
        m_resizeRect = CGRect.Empty;
        base.ViewDidEndLiveResize();
    }
    protected void OnResize() {
        Console.WriteLine("OnResize " + this.Bounds.ToString() );
    }

Answer 1

您可以订阅调整大小通知。

将观察者添加到默认通知中心:

NSObject NSWindowDidResizeNotificationObject;
public override void ViewDidLoad ()
{
    base.ViewDidLoad ();
    NSWindowDidResizeNotificationObject = NSNotificationCenter.DefaultCenter.AddObserver (new NSString ("NSWindowDidResizeNotification"), ResizeObserver, null);
}

NSNotification 操作:

public void ResizeObserver (NSNotification notify)
{
    var r = this.View.Frame;
    Console.WriteLine ("{0}:{1}:{1}", notify.Name, r.Height, r.Width);
}

删除观察者(并释放内存):

NSNotificationCenter.DefaultCenter.RemoveObserver (NSWindowDidResizeNotificationObject);

示例输出:

NSWindowDidResizeNotification:740:740
NSWindowDidResizeNotification:715:715
NSWindowDidResizeNotification:681:681
NSWindowDidResizeNotification:642:642