sctong

xcode7.2 & swift2.1.1

MainTabBarController中的PlusButtonSubclass需要再添加如下代码：

//修复点击中间按钮无法响应
class func plusButton() -> AnyObject! {
    let button:PlusButtonSubclass =  PlusButtonSubclass()
    button.setImage(UIImage(named: "icon_middle_add"), forState: UIControlState.Normal)
    button.titleLabel!.textAlignment = NSTextAlignment.Center;
    button.adjustsImageWhenHighlighted = false;
    button.addTarget(button, action: "buttonClicked:", forControlEvents: UIControlEvents.TouchUpInside)
    
    //修改下按钮的大小
    button.frame.size.width = 50;
    button.frame.size.height = 50;
    
    return  button
}