通过click - XCode 6 Swift更改UIButton的图像

// 假设你有一个 UIButton 实例 button
let button = UIButton()

// 设置按钮的图像
button.setImage(UIImage(named: "newImageName"), for: .normal)

// 确保图像已添加到项目中
button.setImage(UIImage(named: "newImageName"), for: .normal)

// 设置图像内容模式
button.imageView?.contentMode = .scaleAspectFit

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let button = UIButton(type: .system)
        button.frame = CGRect(x: 50, y: 50, width: 100, height: 50)
        button.setTitle("Click Me", for: .normal)
        
        // 更改按钮图像
        button.setImage(UIImage(named: "newImageName"), for: .normal)
        
        // 设置图像内容模式
        button.imageView?.contentMode = .scaleAspectFit
        
        button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
        
        view.addSubview(button)
    }
    
    @objc func buttonTapped() {
        print("Button tapped!")
    }
}