ios - 如何将按钮水平设置在中心

Question

我正在尝试以编程方式创建一个按钮，并且希望该按钮位于底部稍上方的位置，并且位于左右两侧的空间位置。目前按钮显示如下

这是代码

func showbutton(){
        let button = UIButton(type: .System) // let preferred over var here
        button.frame = CGRectMake(8, 550, 415, 50)

        button.backgroundColor = UIColor.greenColor()
        button.setTitle("Add new request", forState: UIControlState.Normal)
        //button.addTarget(self, action: "Action:", forControlEvents: UIControlEvents.TouchUpInside)
        self.view.addSubview(button)
        // Set background color to see if label is centered

        view.addSubview(button)

    }

Answer 1

正如我在评论中提到的，我以编程方式使用 AutoLayout(并且您应该使用 AutoLayout)的首选是 SnapKit .

func showbutton(){
    let button = UIButton(type: .System) // let preferred over var here
    button.frame = CGRectMake(8, 550, 415, 50)

    button.backgroundColor = UIColor.greenColor()
    button.setTitle("Add new request", forState: UIControlState.Normal)
    //button.addTarget(self, action: "Action:", forControlEvents: UIControlEvents.TouchUpInside)
    self.view.addSubview(button)
    // Set background color to see if label is centered

    view.addSubview(button)
    // create the constraints
    button.snp_makeConstraints { (make) -> Void in
        make.centerY.equalTo(view)
    }
}