override func viewDidLoad() {
super.viewDidLoad()

//        var button:UIButton = UIButton(type:.ContactAdd)
        var button:UIButton = UIButton(type:.InfoDark);

//设置按钮位置和大小

 button.frame = CGRectMake(10,200,100,30)

//设置frame可以简化为

 var button2 = UIButton(frame:CGRectMake(10,250,100)) 

//按钮文字以及文字颜色的设置

button2.setTitle("button2",forState: UIControlState.Normal)
        button2.setTitleColor(UIColor.blueColor(),forState: UIControlState.Normal)

//添加button2到self.view

self.view.addSubview(button2);

button.setTitle("按钮",forState: UIControlState.Normal);
    //设置按钮图片

button2.setImage(UIImage(named:"icon"),forState: UIControlState.Normal)

self.view .addSubview(button);
    //设置背景颜色

//        button.backgroundColor = UIColor.redColor()

//设置button点击事件（这里跟oc有点区别 oc是@selector）

button2.addTarget(self,action: #selector(buttonPressed),forControlEvents: UIControlEvents.TouchUpInside)

}
//        不传递触摸对象（即点击的按钮）

func buttonPressed(){
        print("tapped")
    }