使用CoreGraphics在monotouch中创建按钮

Question

我正在尝试使用CoreGraphics在monotouch上创建一个按钮.我无法弄清楚如何在推动时更改按钮颜色.我尝试重写TouchesBegan和TouchesEnded方法,但我无法弄清楚如何改变颜色.

Answer 1

您可以通过两种方式处理背景颜色.您只需设置BackgroundColor属性即可.这应该会自动改变颜色.或者,如果要将颜色存储为要用于FillRect的私有变量,则需要调用SetNeedsDisplay强制调用Draw.

public override void TouchesBegan (MonoTouch.Foundation.NSSet touches, UIEvent evt)
{
    base.TouchesBegan (touches, evt);
    this.BackgroundColor = UIColor.Green;
    backColor2 = UIColor.Yellow;
    this.SetNeedsDisplay ();
}

public override void TouchesEnded (MonoTouch.Foundation.NSSet touches, UIEvent evt)
{
    base.TouchesEnded (touches, evt);
    this.BackgroundColor = UIColor.Red;
    backColor2 = UIColor.Blue;
    this.SetNeedsDisplay ();
}

public override void Draw (RectangleF rect)
{
    base.Draw (rect);

    using (CGContext context = UIGraphics.GetCurrentContext ()) {
        RectangleF rect2 = this.Bounds;
        rect2.X += 10;
        rect2.Y += 5;
        rect2.Width -= 20;
        rect2.Height -= 10;

        backColor2.SetFill ();
        context.FillRect (rect2);
    }
}