UITableView 以编程方式调用滑动操作 [英] UITableView invoke swipe actions programmatically

问题描述

我有一个 UITableView，用户可以在其中向左滑动以显示操作(例如在 iOS 8 邮件中).这一切都按预期工作.我想在用户点击单元格的某个部分时触发它.如何以编程方式调用此幻灯片操作?

I have a UITableView where the user can swipe left to reveal actions (like in iOS 8 mail). That all works as expected. I want to trigger this when the user taps on a certain part of the cell. How can I invoke this slide action programmatically?

当前行为:用户必须向左滑动单元格才能显示操作按钮.

Current behavior: User must swipe the cell left to disclose the action buttons.

期望的行为:用户在单元格上点击(一个操作按钮).单元格滑过以显示操作按钮.

Desired behavior: User taps (an actions button) on the cell. Cell slides over to disclose the action buttons.

推荐答案

好吧，我找不到以编程方式执行此操作的方法，但我想出了这个解决方法.当用户点击单元格时，我将其动画(平移)到左侧以暂时显示假的滑动我"按钮.这很快被逆转，因此细胞恢复正常.这提供了一个视觉提示，让用户知道他们可以滑动单元格:

Well I couldn't find a way to do this programmatically, but I came up with this workaround. When the user taps the cell, I animated (pan) it to the left to momentarily reveal afake "Swipe Me" button. This is quickly reversed so the cell is back to normal. This provides a visual cue to let the user know that they can swipe the cell:

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
    UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];

    __block UILabel *swipeLabel = [[UILabel alloc]initWithFrame:CGRectMake(cell.bounds.size.width,
                                                                   0,
                                                                   200,
                                                                   cell.bounds.size.height)];

    swipeLabel.text = @"  Swipe Me";
    swipeLabel.backgroundColor = [UIColor greenColor];
    swipeLabel.textColor = [UIColor whiteColor];
    [cell addSubview:swipeLabel];

    [UIView animateWithDuration:0.3 animations:^{
        [cell setFrame:CGRectMake(cell.frame.origin.x - 100, cell.frame.origin.y, cell.bounds.size.width, cell.bounds.size.height)];
    } completion:^(BOOL finished) {
        [UIView animateWithDuration:0.3 animations:^{
            [cell setFrame:CGRectMake(cell.frame.origin.x + 100, cell.frame.origin.y, cell.bounds.size.width, cell.bounds.size.height)];
        } completion:^(BOOL finished) {
            [swipeLabel removeFromSuperview];
            swipeLabel = nil;
        }];
    }];
}

希望这对某人有所帮助.

Hope this helps someone.

请注意，您需要将 tableViewCell 的选择类型设置为 none.否则灰色条会遮住它.

Note that you need to set your tableViewCell's selection type to none. Else the gray bar will obscure it.

更新.我想我会发布一个更Swifty的版本:

Update. I thought I'd post a more Swifty version:

func previewActions(forCellAt indexPath: IndexPath) {
    guard let cell = tableView.cellForRow(at: indexPath) else {
        return
    }

    let label: UILabel = {
        let label = UILabel(frame: CGRect.zero)
        label.text = "  Swipe Me  "
        label.backgroundColor = .blue
        label.textColor = .white
        return label
    }()

    // Figure out the best width and update label.frame
    let bestSize = label.sizeThatFits(label.frame.size)
    label.frame = CGRect(x: cell.bounds.width - bestSize.width, y: 0, width: bestSize.width, height: cell.bounds.height)
    cell.insertSubview(label, belowSubview: cell.contentView)

    UIView.animate(withDuration: 0.3, animations: {
        cell.transform = CGAffineTransform.identity.translatedBy(x: -label.bounds.width, y: 0)
        label.transform = CGAffineTransform.identity.translatedBy(x: label.bounds.width, y: 0)
    }) { (finished) in
        UIView.animateKeyframes(withDuration: 0.3, delay: 0.25, options: [], animations: {
            cell.transform = CGAffineTransform.identity
            label.transform = CGAffineTransform.identity
        }, completion: { (finished) in
            label.removeFromSuperview()
        })
    }
}

func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
    previewActions(forCellAt: indexPath)
    return
}

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