Swift中UIImageView实现淡入动画后点击触发淡出效果的问题咨询

核心修改步骤 #

• 给UIImageView开启用户交互，添加点击手势识别器
• 原有淡入动画新增allowUserInteraction配置，保证动画过程中可响应交互
• 点击事件中先校验动画是否处于运行状态，再执行淡出逻辑

代码实现 #

1. 修改原有淡入动画代码

// 新增.allowUserInteraction选项，允许动画运行时响应交互
UIView.animate(withDuration: 0.5, delay: delay, options: [.curveEaseOut, .allowUserInteraction], animations: {
    uiImageView.alpha = 1.0
})

2. 给UIImageView添加点击手势

// UIImageView默认关闭用户交互，需要手动开启
uiImageView.isUserInteractionEnabled = true
let tapGesture = UITapGestureRecognizer(target: self, action: #selector(onImageViewClicked(_:)))
uiImageView.addGestureRecognizer(tapGesture)

3. 实现点击事件处理逻辑

@objc private func onImageViewClicked(_ gesture: UITapGestureRecognizer) {
    guard let targetImageView = gesture.view as? UIImageView else { return }
    // 校验当前视图是否有正在运行的动画
    guard let animKeys = targetImageView.layer.animationKeys(), !animKeys.isEmpty else { return }
    
    // 移除正在运行的淡入动画，避免动画冲突
    targetImageView.layer.removeAllAnimations()
    // 执行淡出动画
    UIView.animate(withDuration: 0.5, delay: 0, options: .curveEaseIn, animations: {
        targetImageView.alpha = 0.0
    }) { _ in
        // 淡出完成后可根据需求添加后续处理逻辑，例如移除视图
        // targetImageView.removeFromSuperview()
    }
}

注意事项 #

• 如果需要更精准的动画状态判断，可以通过targetImageView.layer.presentation()?.alpha获取当前显示层的实际alpha值，和视图的最终alpha值对比判断动画是否运行中
• 淡出动画的时长、缓动效果可根据业务需求自行调整参数

内容的提问来源于stack exchange，提问作者muhammad ali