Swift开发：如何在ImageView的四个角添加按钮

直接通过frame设置按钮位置的方式，在视图尺寸变化（比如屏幕旋转、父视图布局更新）时容易出现错位问题，推荐使用AutoLayout自动布局来实现，能保证按钮始终固定在ImageView的四个角。

修改后的完整代码如下：

private func createResisedButtons() {
    // 定义按钮尺寸
    let buttonSize: CGFloat = 30
    // 可选：按钮和边角的间距，默认0可按需调整为8、10等值
    let edgeInset: CGFloat = 0
    
    for index in 0..<4 {
        let button = UIButton(type: .custom)
        button.backgroundColor = .blue
        button.addTarget(self, action: #selector(buttonTapped), for: .touchUpInside)
        // 必须关闭自动约束转换，否则手动添加的约束会失效
        button.translatesAutoresizingMaskIntoConstraints = false
        imageView.addSubview(button)
        
        // 根据索引绑定对应角的约束
        switch index {
        case 0: // 左上角
            NSLayoutConstraint.activate([
                button.leadingAnchor.constraint(equalTo: imageView.leadingAnchor, constant: edgeInset),
                button.topAnchor.constraint(equalTo: imageView.topAnchor, constant: edgeInset),
                button.widthAnchor.constraint(equalToConstant: buttonSize),
                button.heightAnchor.constraint(equalToConstant: buttonSize)
            ])
        case 1: // 右上角
            NSLayoutConstraint.activate([
                button.trailingAnchor.constraint(equalTo: imageView.trailingAnchor, constant: -edgeInset),
                button.topAnchor.constraint(equalTo: imageView.topAnchor, constant: edgeInset),
                button.widthAnchor.constraint(equalToConstant: buttonSize),
                button.heightAnchor.constraint(equalToConstant: buttonSize)
            ])
        case 2: // 左下角
            NSLayoutConstraint.activate([
                button.leadingAnchor.constraint(equalTo: imageView.leadingAnchor, constant: edgeInset),
                button.bottomAnchor.constraint(equalTo: imageView.bottomAnchor, constant: -edgeInset),
                button.widthAnchor.constraint(equalToConstant: buttonSize),
                button.heightAnchor.constraint(equalToConstant: buttonSize)
            ])
        case 3: // 右下角
            NSLayoutConstraint.activate([
                button.trailingAnchor.constraint(equalTo: imageView.trailingAnchor, constant: -edgeInset),
                button.bottomAnchor.constraint(equalTo: imageView.bottomAnchor, constant: -edgeInset),
                button.widthAnchor.constraint(equalToConstant: buttonSize),
                button.heightAnchor.constraint(equalToConstant: buttonSize)
            ])
        default:
            break
        }
        
        buttonsArray.append(button)
    }
}

@objc private func buttonTapped(_ sender: UIButton) {
    // 处理按钮点击事件，通过数组索引判断触发的按钮
    if let index = buttonsArray.firstIndex(of: sender) {
        print("第\(index+1)个按钮被点击")
    }
}

关键说明： #

• 必须设置button.translatesAutoresizingMaskIntoConstraints = false，关闭系统自动生成的约束，否则手动添加的AutoLayout约束会被覆盖。
• 使用NSLayoutConstraint.activate批量激活约束，比单独设置更高效。
• 如果需要调整按钮和ImageView边角的距离，修改edgeInset的值即可，不用逐个修改约束的constant。

内容的提问来源于stack exchange，提问作者Grigore Rosca