为 UITableView 滑动操作设置自定义字体（UIContextualAction）

Question

UIContextualAction中的标题如何设置自定义字体？

我试过UIAppearance，但没有任何运气......

干杯！ :)

Answer 1

我找到了一种方法来使用图像属性而不是标题...

标准字体（删除/重命名）

自定义字体（删除/重命名）

要创建标签的图像，我有这个扩展：

extension UIImage {

    /// This method creates an image of a view
    convenience init?(view: UIView) {

        // Based on https://stackoverflow.com/a/41288197/1118398
        let renderer = UIGraphicsImageRenderer(bounds: view.bounds)
        let image = renderer.image { rendererContext in
            view.layer.render(in: rendererContext.cgContext)
        }

        if let cgImage = image.cgImage {
            self.init(cgImage: cgImage, scale: UIScreen.main.scale, orientation: .up)
        } else {
            return nil
        }
    }
}

然后我有：

override func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {

    let action = UIContextualAction(style: .destructive, title: nil) { action, view, completion in
        // Your swipe action code!
    }
    let label = UILabel()
    label.text = // Your swipe action text!
    label.font = // Your custom font!
    label.sizeToFit()
    action.image = UIImage(view: label)

    return UISwipeActionsConfiguration(actions: [action])
}

Answer 2

我最近发现了一种方法，通过使用按钮 titleLabel 而不是图像属性来执行此操作，这样您就可以保持对文本和图像进行操作的能力。

正如你将看到的，我们需要做一些尴尬的事情......

func tableView(_ tableView: UITableView, willBeginEditingRowAt indexPath: IndexPath) {

    if #available(iOS 13.0, *) {
        for subview in tableView.subviews {
            if NSStringFromClass(type(of: subview)) == "_UITableViewCellSwipeContainerView" {
                for swipeContainerSubview in subview.subviews {
                    if NSStringFromClass(type(of: swipeContainerSubview)) == "UISwipeActionPullView" {
                        for case let button as UIButton in swipeContainerSubview.subviews {
                            button.titleLabel?.font = .systemFont(ofSize: 12)
                        }
                    }
                }
            }
        }
    } else {
        for subview in tableView.subviews {
            if NSStringFromClass(type(of: subview)) == "UISwipeActionPullView" {
                for case let button as UIButton in subview.subviews {
                    button.titleLabel?.font = .systemFont(ofSize: 12)
                }
            }
        }
    }
 }

Answer 3

已针对 Swift 5 和 iOS 13 更新

以下功能允许您为滑动操作设置字体和色调。

要开始使用，请将扩展名添加到 UITableView。

extension UITableView {
    /// Iterates over all subviews of a `UITableView` instance and applies the supplied font to all labels withing the UISwipeAction's array.
    /// - Parameter font: The font that should be applied to the labels.
    /// - Parameter tintColor: The tint color that should be applied to image views and labels
    /// - Parameter ignoreFirst: Whether or not the first swipe action should be ignored when applying tints
    public func setSwipeActionFont(_ font: UIFont, withTintColor tintColor: UIColor? = nil, andIgnoreFirst ignoreFirst: Bool = false) {
        for subview in self.subviews {
            //Confirm that the view being touched is within a swipe container
            guard NSStringFromClass(type(of: subview)) == "_UITableViewCellSwipeContainerView" else {
                continue
            }

            //Re-iterate subviews and confirm that we are touching a swipe view
            for swipeContainerSubview in subview.subviews {
                guard NSStringFromClass(type(of: swipeContainerSubview)) == "UISwipeActionPullView" else {
                    continue
                }

                //Enumerate subviews and confirm that we are touching a button
                for (index, view) in swipeContainerSubview.subviews.filter({ $0 is UIButton }).enumerated() {
                    //Set Font
                    guard let button = view as? UIButton else {
                        continue
                    }
                    button.titleLabel?.font = font
                    
                    //Set Tint Conditionally (based on index)
                    guard index > 0 || !ignoreFirst else {
                        continue
                    }
                    button.setTitleColor(tintColor, for: .normal)
                    button.imageView?.tintColor = tintColor
                }
            }
        }
    }
}

在您的委托中，将以下功能添加到您的 UITableViewDataSource.WillBeginEditing(UITableView, IndexPath) 方法中。根据需要替换字体和颜色参数。色调颜色是可选的。

self?.tableView.setSwipeActionFont(.systemFont(ofSize: 24.0, withTintColor: .systemRed)

Answer 4

针对目标 C

创建一个方法

- (UIImage *)createImageFromLabel:(UILabel *)label
{
    UIGraphicsBeginImageContext(label.bounds.size);

    [label.layer renderInContext:UIGraphicsGetCurrentContext()];;

    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

    return image;
}

此方法将从您的标签返回图像。

现在在 tableview 数据源方法中

- (UISwipeActionsConfiguration *)tableView:(UITableView *)tableView trailingSwipeActionsConfigurationForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UIContextualAction *action = [UIContextualAction contextualActionWithStyle:UIContextualActionStyleDestructive title:nil handler:^(UIContextualAction * _Nonnull action, __kindof UIView * _Nonnull sourceView, void (^ _Nonnull completionHandler)(BOOL)) {
        
        //Your code here
    }];

    action.backgroundColor = [UIColor redColor];

    // Create label as you want view for delete button
    UILabel *label = [[UILabel alloc] init];
    label.font = [UIFont systemFontSize:14];
    label.text = @"Your Text";
    label.textColor = [UIColor whiteColor];
    [label sizeToFit];
    UIImage *image =  [self createImageFromLabel:label];

    action.image = image;

    UISwipeActionsConfiguration *actions = [UISwipeActionsConfiguration configurationWithActions:@[action]];

    return actions;
}