swift - UIButton 无法在 UITableViewCell 中的所有设备上居中 - Swift

Question

我创建了一个自定义 UITableViewCell，它以编程方式添加到我的 View Controller 中。自定义单元格包含一个按钮。问题是我无法实现按钮在所有设备上居中。如果它是 5s 模拟器，并且我使用 self.frame.width 作为按钮框架的 x 坐标，那么它会居中 - 但不是在 6 或 6s 上，但如果我使用 super.frame.width 作为 x 坐标，然后以 6 模拟器为中心。有谁知道如何让它在所有设备屏幕上居中？这是我的自定义按钮的代码，我只需将其作为 UITableViewCell 返回到我的 View Controller 的 tableView 委托(delegate)中...

import Foundation
import UIKit

public class ButtonCell: UITableViewCell {

    //Custom button to be added to the last cell to submit
    let buttonImage = UIImage(named: "add_pub_button") as UIImage?
    let button = UIButton(type: UIButtonType.Custom) as UIButton

    /**
     Creates the ButtonCell

     - parameter style:           A constant indicating a cell style. See UITableViewCellStyle for descriptions of these constants.
     - parameter reuseIdentifier: A string used to identify the cell object if it is to be reused for drawing multiple rows of a table view. Pass nil if the cell object is not to be reused. You should use the same reuse identifier for all cells of the same form.

     - returns: An initialized TextInputCell object or nil if the object could not be created.
     */
    override public init(style: UITableViewCellStyle, reuseIdentifier: String?) {
        super.init(style: style, reuseIdentifier: reuseIdentifier)
        setup()
    }

    private func setup() {

        //Overhangs the view slightly to avoid invalid constraints.
        self.clipsToBounds = true
        self.backgroundView = nil
        self.backgroundColor = nil
        self.tintColor = nil
        self.selectionStyle = .None

        button.frame = CGRectMake((self.frame.width - 134)/2, 0, 134, 44)
        button.tintColor = nil
        button.backgroundColor = nil
        button.setImage(buttonImage, forState: .Normal)

        self.contentView.addSubview(button)
    }

    /**
     Needed for initialization from a storyboard.
     - parameter aDecoder: An unarchiver object.
     - returns: An initialized ButtonCell object or nil if the object could not be created.
     */
    required public init?(coder aDecoder: NSCoder) {
        super.init(coder: aDecoder)
        setup()
    }
}

Answer 1

只需在layoutSubviews方法中设置框架相关操作

例如，

    private func setup() {

    //Overhangs the view slightly to avoid invalid constraints.
    self.clipsToBounds = true
    self.backgroundView = nil
    self.backgroundColor = nil
    self.tintColor = nil
    self.selectionStyle = .None

    //no need of setting the frame of button hear 
    //at the time initialisation there is no frame available for cell
    //button.frame = CGRectMake((self.frame.width - 134)/2, 0, 134, 44) 
    button.tintColor = nil
    button.backgroundColor = nil
    button.setImage(buttonImage, forState: .Normal)

    self.contentView.addSubview(button)
}

//set it hear because frame of the cell available hear
 override func layoutSubviews() {
    super.layoutSubviews()
    button.frame = CGRectMake((self.frame.width - 134)/2, 0, 134, 44)
}