如何创建在MonoTouch的继承视图UIAppearance代理？(How to create a

我创建的子类UIButton充当内自定义后退按钮UIBarButtonItem ：

 - - - - - - - - - - - - - - - - - 
|         UIBarButtonItem         |

|     ------------------------    |
     /                       |
|    \ BackButton : UIButton |    |
      ------------------------
|  _  _  _  _  _  _  _  _  _  _  _|

当我转换我的代码使用UIAppearance ，我注意到BackButton.Appearance是，unsuprisingly，从继承UIButton.Appearance ，因此改变它会改变所有UIButton小号整个应用程序，而不是只是我的自定义按钮。

我知道我可以使用AppearanceWhenContainedIn但是，因为UIBarButtonItem不是外观的容器，我不得不插入它们之间的另一种观点认识到后退按钮，这是我不想做的事。

如何提供一个UIAppearance为我的自定义代理UIButton子类，在所有可用的方法UIButton.UIButtonAppearance ？我注意到，它的构造是内部的。

Answer 1:

虽然有可能是一个简单的答案，我结束了继承UIAppearance直接复制粘贴相关一块UIButton和UIButton+UIButtonAppearance从MonoDevelop的C＃反汇编结合实施，在这里和那里固定内部字段。

内部BackButton ：

static readonly IntPtr class_ptr = Class.GetHandle(typeof(BackButton));

public new static BackButtonAppearance Appearance
{
    get {
        return new BackButtonAppearance (Messaging.IntPtr_objc_msgSend (class_ptr, UIAppearance.SelectorAppearance));
    }
}

public new static BackButtonAppearance AppearanceWhenContainedIn (params Type[] containers)
{
    return new BackButtonAppearance (UIAppearance.GetAppearance (class_ptr, containers));
}

嵌套BackButtonAppearance ：

public class BackButtonAppearance : UIAppearance {
    public BackButtonAppearance(IntPtr handle) : base(handle) { }

    // These are copied from UIButton disassembly:

    static readonly IntPtr selSetBackgroundImageForState_ = Selector.GetHandle ("setBackgroundImage:forState:");
    static readonly IntPtr selSetTitleShadowColorForState_ = Selector.GetHandle ("setTitleShadowColor:forState:");            
    static readonly IntPtr selSetTitleColorForState_ = Selector.GetHandle ("setTitleColor:forState:");

    // These are copied from UIButton+UIButtonAppearance disassembly,
    // with internal UIButton.selSet* fields replaced by fields declared above.

    [Export ("setBackgroundImage:forState:"), CompilerGenerated]
    public virtual void SetBackgroundImage (UIImage image, UIControlState forState)
    {
        UIApplication.EnsureUIThread ();
        if (this.IsDirectBinding) {
            Messaging.void_objc_msgSend_IntPtr_UInt32 (base.Handle, selSetBackgroundImageForState_, (image != null) ? image.Handle : IntPtr.Zero, (uint)forState);
        } else {
            Messaging.void_objc_msgSendSuper_IntPtr_UInt32 (base.SuperHandle, selSetBackgroundImageForState_, (image != null) ? image.Handle : IntPtr.Zero, (uint)forState);
        }
    }


    [Export ("setTitleColor:forState:"), CompilerGenerated]
    public virtual void SetTitleColor (UIColor color, UIControlState forState)
    {
        UIApplication.EnsureUIThread ();
        if (this.IsDirectBinding) {
            Messaging.void_objc_msgSend_IntPtr_UInt32 (base.Handle, selSetTitleColorForState_, (color != null) ? color.Handle : IntPtr.Zero, (uint)forState);
        } else {
            Messaging.void_objc_msgSendSuper_IntPtr_UInt32 (base.SuperHandle, selSetTitleColorForState_, (color != null) ? color.Handle : IntPtr.Zero, (uint)forState);
        }
    }

    [Export ("setTitleShadowColor:forState:"), CompilerGenerated]
    public virtual void SetTitleShadowColor (UIColor color, UIControlState forState)
    {
        UIApplication.EnsureUIThread ();
        if (this.IsDirectBinding) {
            Messaging.void_objc_msgSend_IntPtr_UInt32 (base.Handle, selSetTitleShadowColorForState_, (color != null) ? color.Handle : IntPtr.Zero, (uint)forState);
        } else {
            Messaging.void_objc_msgSendSuper_IntPtr_UInt32 (base.SuperHandle, selSetTitleShadowColorForState_, (color != null) ? color.Handle : IntPtr.Zero, (uint)forState);
        }
    }
}

这使我能够把我的自定义视图，支持UIAppearance风格的API。

Answer 2:

添加答案的完整性。

使用BackButton.GetAppearance<BackButton>()代替BackButton.Appearance 。