Question

我希望在长时间按下后获得快照，我会让它正常工作。我正在通过以下代码创建快照：

func customSnapShotFrom(view:UIView) -> UIView { // calling this with UITableViewCell input
    let snapshot:UIView = view.snapshotViewAfterScreenUpdates(false) // here I tried true and false
    snapshot.layer.masksToBounds = false
    snapshot.layer.cornerRadius = 0.0
    snapshot.layer.shadowOffset = CGSizeMake(2.0, 2.0)
    snapshot.layer.shadowOpacity = 1.0
    return snapshot
}

它正在运行，但有时我会在输出中收到此消息：

快照未渲染的视图会导致空白快照。确保您的视图至少在之前呈现过一次屏幕更新后的快照或快照。

我只为一些细胞（只有少数细胞）而不是总是得到它。有时它会在其返回nil时从该单元格生成快照。我已经检查过了，我总是输入信号。那为什么呢？为什么渲染结果为空快照？感谢

修改我在手表识别器中添加了手势识别器：

let longPress = UILongPressGestureRecognizer(target: self, action: "longPressDetected:")
self.tableView.addGestureRecognizer(longPress)

我正在longPressDetected方法创建快照：

func longPressDetected(sender: AnyObject) {
    ...
    switch (state) {
    case UIGestureRecognizerState.Began :

            ...
            let cell:UITableViewCell = self.tableView.cellForRowAtIndexPath(indexPath)!
            snapshot = self.customSnapShotFrom(cell)
    ...

我的快速解决方案感谢kirander answer：

func customSnapShotFrom(view:UIView) -> UIView {

    UIGraphicsBeginImageContextWithOptions(view.bounds.size, false, 0)
    view.layer.renderInContext(UIGraphicsGetCurrentContext()!)
    let cellImage = UIGraphicsGetImageFromCurrentImageContext()
    UIGraphicsEndImageContext()

    let imageView = UIImageView(image: cellImage)
    imageView.layer.masksToBounds = false
    imageView.layer.cornerRadius = 0.0
    imageView.layer.shadowOffset = CGSizeMake(2.0, 2.0)
    imageView.layer.shadowRadius = 4.0
    imageView.layer.shadowOpacity = 1.0
    return imageView
}

Answer 1

从here

尝试此代码

// make an image from the pressed tableview cell
UIGraphicsBeginImageContextWithOptions(inputView.bounds.size, NO, 0);
[inputView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *cellImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

// create and image view that we will drag around the screen
UIView *snapshot = [[UIImageView alloc] initWithImage:cellImage];

获取某些单元格的快照不起作用

1 个答案: