Swift中如何独立调整UIView的宽度与高度

原有的捏合手势默认按统一比例缩放，所以只能同时调整宽高，你可以根据需求选择以下任意一种方案实现独立调整：

方案1：改造捏合手势实现非等比缩放 #

双指横向拉伸仅调整宽度、纵向拉伸仅调整高度，斜向拉伸可同时独立调整宽高，无需额外添加UI元素：

第一步：添加状态存储属性 #

// 类内部添加属性，存储捏合初始状态
private var initialViewSize: CGSize = .zero
private var initialTouchPoints: [CGPoint] = []

第二步：替换原有捏合手势处理方法 #

@objc func pinchRecognized(pinch: UIPinchGestureRecognizer) {
    guard let view = pinch.view else { return }
    
    switch pinch.state {
    case .began:
        // 记录捏合开始时的视图尺寸和两个触摸点坐标
        initialViewSize = view.bounds.size
        initialTouchPoints = (0..<pinch.numberOfTouches).compactMap { pinch.location(ofTouch: $0, in: self.view) }
    case .changed:
        guard initialTouchPoints.count == 2 else { return }
        // 获取当前两个触摸点坐标
        let currentTouchPoints = (0..<pinch.numberOfTouches).compactMap { pinch.location(ofTouch: $0, in: self.view) }
        guard currentTouchPoints.count == 2 else { return }
        
        // 分别计算X、Y轴的独立缩放比例
        let initialXDiff = abs(initialTouchPoints[0].x - initialTouchPoints[1].x)
        let currentXDiff = abs(currentTouchPoints[0].x - currentTouchPoints[1].x)
        let scaleX = initialXDiff > 0 ? currentXDiff / initialXDiff : 1
        
        let initialYDiff = abs(initialTouchPoints[0].y - initialTouchPoints[1].y)
        let currentYDiff = abs(currentTouchPoints[0].y - currentTouchPoints[1].y)
        let scaleY = initialYDiff > 0 ? currentYDiff / initialYDiff : 1
        
        // 应用新尺寸，添加最小宽高限制避免缩到无法操作
        view.bounds.size = CGSize(
            width: max(50, initialViewSize.width * scaleX),
            height: max(50, initialViewSize.height * scaleY)
        )
    default:
        break
    }
}

方案2：添加边缘拖拽锚点（操作更直观） #

在视图右下角添加可拖拽的调整把手，用户拖动把手即可自由调整宽高，学习成本更低：

第一步：添加状态存储属性 #

// 类内部添加属性
private var originalSize: CGSize = .zero
// 尺寸调整把手，可自定义样式
private var resizeHandle: UIView = {
    let view = UIView(frame: CGRect(x: 0, y: 0, width: 30, height: 30))
    view.backgroundColor = .systemBlue
    view.layer.cornerRadius = 15
    return view
}()

第二步：修改手势添加方法 #

func addGestures() {
    // 原有拖动视图的代码保留
    let gestureRecognizer = UIPanGestureRecognizer(target: self, action: #selector(handlePan))
    gestureRecognizer.delegate = self
    myView.addGestureRecognizer(gestureRecognizer)
    
    myView.isUserInteractionEnabled = true
    myView.isMultipleTouchEnabled = true
    
    // 添加尺寸调整把手
    myView.addSubview(resizeHandle)
    resizeHandle.translatesAutoresizingMaskIntoConstraints = false
    NSLayoutConstraint.activate([
        resizeHandle.trailingAnchor.constraint(equalTo: myView.trailingAnchor, constant: 10),
        resizeHandle.bottomAnchor.constraint(equalTo: myView.bottomAnchor, constant: 10),
        resizeHandle.widthAnchor.constraint(equalToConstant: 30),
        resizeHandle.heightAnchor.constraint(equalToConstant: 30)
    ])
    // 给把手添加拖拽手势
    let resizePan = UIPanGestureRecognizer(target: self, action: #selector(handleResizePan(_:)))
    resizeHandle.addGestureRecognizer(resizePan)
    
    // 原有等比捏合手势如果不需要可以直接删除，也可保留共存
    // let pinchGesture = UIPinchGestureRecognizer(target: self, action:#selector(pinchRecognized(pinch:)))
    // pinchGesture.delegate = self
    // myView.addGestureRecognizer(pinchGesture)
}

第三步：添加尺寸调整手势处理方法 #

@objc func handleResizePan(_ gesture: UIPanGestureRecognizer) {
    guard let resizeView = gesture.view, let targetView = resizeView.superview else { return }
    
    switch gesture.state {
    case .began:
        originalSize = targetView.bounds.size
    case .changed:
        let translation = gesture.translation(in: self.view)
        // 按拖拽偏移调整宽高，添加最小尺寸限制
        let newWidth = max(50, originalSize.width + translation.x)
        let newHeight = max(50, originalSize.height + translation.y)
        targetView.bounds.size = CGSize(width: newWidth, height: newHeight)
    default:
        break
    }
}

注意事项 #

• 尽量直接修改视图的bounds.size属性实现尺寸调整，不要使用transform缩放，避免后续修改frame时出现坐标异常
• 两种方案可以共存，也可根据产品交互需求单独使用
• 最小宽高限制的数值可以根据业务需求自行修改

内容的提问来源于stack exchange，提问作者Abhishek Kumar