Question

我正在处理一个表格视图，我想要在加载时为其单元格设置动画。我在1.5秒内将alpha淡入淡出从0设置为1。我遇到的问题是每次调用cellForRowAt indexPath时都会生成动画。有没有一个很好的方法来做这个，所以单元格只动画一次，而不是每次调用cellForRowAt IndexPath？任何帮助表示赞赏。谢谢！

// function to configure custom table view cell 
func configCell(place: Place) {
    // hide image and label before image is loaded
    headlineImage.alpha = 0
    headlineLabel.alpha = 0
    headlineLabel.text = place.name
    // set image asynchronously
    headlineImage.sd_setImage(with: URL(string: "ImageUrl"), placeholderImage: UIImage(named: "restaurant"), options: .continueInBackground) { (_, _, _, _ ) in
            // image download complete fade in image
            print("COMPLETED SD SET IMAGE")
            UIView.animate(withDuration: 1.5, animations: {
                self.headlineImage.alpha = 1
                self.headlineLabel.alpha = 1
            })
    }

}

Answer 1

这样的事情可能有所帮助。

创建全局变量

var isFirstLoad = true

然后在你的configCell方法中，将动画包装在if-block内，并将标志设置为false

func configCell(place: Place) {
    headlineLabel.text = place.name    
    if isFirstLoad == true {
        isFirstLoad = false
        headlineImage.alpha = 0
        headlineLabel.alpha = 0
        headlineImage.sd_setImage(with: URL(string: "ImageUrl"), placeholderImage: UIImage(named: "restaurant"), options: .continueInBackground) { (_, _, _, _ ) in
            print("COMPLETED SD SET IMAGE")
            UIView.animate(withDuration: 1.5, animations: {
                self.headlineImage.alpha = 1
                self.headlineLabel.alpha = 1
            })
        }
    }
}

如何仅为tableViewCell制作一次动画？

1 个答案: