swift中的扩展

import UIKit

///自定义，其实就是UIButtom里面加一个方法
extension UIButton{

///加一个class，其实就相当于oc中，前面加一个“+”,个nav的item
class func add_Buttom_Nav(imageName : String,target:AnyObject,action:Selector)-> UIBarButtonItem{

let button = UIButton();
button.setImage(UIImage(named:imageName), forState: .Normal);
button.setImage(UIImage(named: imageName+"_highlighted"), forState: .Highlighted);
button.addTarget(target, action: action, forControlEvents:.TouchDown);
button.sizeToFit();//大小和item适配

return UIBarButtonItem(customView: button);
}
}

//添加nav的左右的item
func add_Naview(){

navigationItem.leftBarButtonItem = UIButton.add_Buttom_Nav("navigationbar_friendattention", target: self, action: "onclick_Left_Buttom");
navigationItem.rightBarButtonItem = UIButton.add_Buttom_Nav("navigationbar_pop", target: self, action: "onclick_Right_Buttom")
}

///扩展类（把谁的代理方法放在里面），显示比较清楚extension Home_ViewDelegate {func delegate_Onclick_Button_Logon() {}func delegate_Onclick_Button_ZuCe() {}}