如何做自定义字体和颜色在UITableViewRowAction没有故事板

Question

我有一个经典的TableView，你可以在这里删除项目，如果你滑动，然后点击按钮。我知道如何在单元格上设置自定义背景，但我找不到如何设置自定义字体和颜色。

谢谢你的帮助！

func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [AnyObject]?  {

    var deleteAction = UITableViewRowAction(style: UITableViewRowActionStyle.Default, 
                   title: "Delete", 
                   handler: { 
                      (action:UITableViewRowAction!, indexPath:NSIndexPath!) -> Void in
                           println("Delete button clicked!")
                   })

    deleteAction.backgroundColor = UIColor.redColor()

    return [deleteAction]
}

Answer 1

如果使用XCode的调试视图层次结构查看当滑动按钮处于活动状态时UITableView中发生的情况，您将看到UITableViewRowAction项转换为名为\u UITableViewCellActionButton，包含在UITableViewCellDeleteConfirmationView中的按钮。更改按钮属性的一种方法是在将其添加到UITableViewCell时拦截它。在UITableViewCell派生类中，编写如下内容：

private let buttonFont = UIFont.boldSystemFontOfSize(13)
private let confirmationClass: AnyClass = NSClassFromString("UITableViewCellDeleteConfirmationView")!

override func addSubview(view: UIView) {
    super.addSubview(view)

    // replace default font in swipe buttons
    let s = subviews.flatMap({$0}).filter { $0.isKindOfClass(confirmationClass) }
    for sub in s {
        for button in sub.subviews {
            if let b = button as? UIButton {
                b.titleLabel?.font = buttonFont
            }
        }
    }
}

Answer 2

我想分享我对ObjC的解决方案，这只是一个技巧，但对我来说是预期的。

- (NSArray<UITableViewRowAction *> *)tableView:(UITableView *)tableView editActionsForRowAtIndexPath:(NSIndexPath *)indexPath
{
    // this just convert view to `UIImage`
    UIImage *(^imageWithView)(UIView *) = ^(UIView *view) {

        UIGraphicsBeginImageContextWithOptions(view.bounds.size, view.opaque, 0.0);
        [view.layer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();
        return image;
    };

    // This is where the magic happen,
    // The width and height must be dynamic (it's up to you how to implement it)
    // to keep the alignment of the label in place
    //
    UIColor *(^getColorWithLabelText)(NSString*, UIColor*, UIColor*) = ^(NSString *text, UIColor *textColor, UIColor *bgColor) {

        UILabel *lbDelete = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 47, 40)];
        lbDelete.font = [UIFont boldSystemFontOfSize:11];
        lbDelete.text = text;
        lbDelete.textAlignment = NSTextAlignmentCenter;
        lbDelete.textColor = textColor;
        lbDelete.backgroundColor = bgColor;

        return [UIColor colorWithPatternImage:imageWithView(lbDelete)];
    };

    // The `title` which is `@"   "` is important it 
    // gives you the space you needed for the 
    // custom label `47[estimated width], 40[cell height]` on this example
    //
    UITableViewRowAction *btDelete;
    btDelete = [UITableViewRowAction
                rowActionWithStyle:UITableViewRowActionStyleDestructive
                title:@"   "
                handler:^(UITableViewRowAction * _Nonnull action, NSIndexPath * _Nonnull indexPath) {
                    NSLog(@"Delete");
                    [tableView setEditing:NO];
                }];
    // Implementation
    //
    btDelete.backgroundColor = getColorWithLabelText(@"Delete", [UIColor whiteColor], [YJColor colorWithHexString:@"fe0a09"]);

    UITableViewRowAction *btMore;
    btMore   = [UITableViewRowAction
                rowActionWithStyle:UITableViewRowActionStyleNormal
                title:@"   "
                handler:^(UITableViewRowAction * _Nonnull action, NSIndexPath * _Nonnull indexPath) {
                    NSLog(@"More");
                    [tableView setEditing:NO];
                }];
    // Implementation
    //
    btMore.backgroundColor = getColorWithLabelText(@"More", [UIColor darkGrayColor], [YJColor colorWithHexString:@"46aae8"]);

    return @[btMore, btDelete];
}

[YJColor的颜色和HexString：

Answer 3

嗯，我发现设置自定义字体的唯一方法是使用UIAppearance协议的appearance方法中包含的appearance。该方法在Swift中还不可用，因此必须在Objective-C中使用。

我在实用工具Objective-C类中创建了一个类方法来设置它：

+ (void)setUpDeleteRowActionStyleForUserCell {

    UIFont *font = [UIFont fontWithName:@"AvenirNext-Regular" size:19];

    NSDictionary *attributes = @{NSFontAttributeName: font,
                      NSForegroundColorAttributeName: [UIColor whiteColor]};

    NSAttributedString *attributedTitle = [[NSAttributedString alloc] initWithString: @"DELETE"
                                                                          attributes: attributes];

    /*
     * We include UIView in the containment hierarchy because there is another button in UserCell that is a direct descendant of UserCell that we don't want this to affect.
     */
    [[UIButton appearanceWhenContainedIn:[UIView class], [UserCell class], nil] setAttributedTitle: attributedTitle
                                                                                          forState: UIControlStateNormal];
}

这是可行的，但绝对不理想。如果在包含层次结构中不包含UIView，那么它最终也会影响披露指示器（我甚至没有意识到披露指示器是UIButton子类）。此外，如果单元格中的UIButton位于单元格的子视图中，则该按钮也会受到此解决方案的影响。

考虑到复杂性，最好只使用一个更可定制的开放源码库作为表格单元格滑动选项。