iOS 7：UITableViewController：更改/替换删除按钮

Question

免责声明：我知道调整这类东西不是最佳做法，因为随着 Apple 决定改变其内部行为，它可能会崩溃。

有一些解决方案，例如 https://stackoverflow.com/a/12511432/271150，似乎适用于以前的 iOS 版本，但不适用于 iOS 7。

查看控件层次结构时，我可以看到 UITableViewCellScrollView 中有一个 UITableViewCellDeleteConfirmationView。但是通过查看 layoutSubviews 或 willTransitionToState 中的 SubViews 集合，只有我自己的视图，UITableViewCellDeleteConfirmationView 没有出现。

那么，有没有人想出如何修改默认删除按钮/视图？

Answer 1

我了解您可能不想覆盖 Apple 的整个实现来编辑表格视图单元格，但我的应用程序遇到了类似的问题。就我而言，当用户从左向右滑动时，我需要两个按钮（更多和丢失）来显示，就像在 iOS7 的新提醒应用程序中一样。而不是使用：

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath

我创建了一个自定义单元格，它隐藏顶层下方的按钮，并使用平移手势识别器移动顶层，显示下方的按钮。因此，我可以完全控制显示哪些按钮以及它们的颜色等（见下文）。

static CGFloat const kEditButtonWidth = 82.0;

@interface MyCustomCell ()
@property (nonatomic, assign) CGFloat firstX;
@property (nonatomic, assign) CGFloat firstY;
@property (nonatomic, strong) UIView *topLayer;
@property (nonatomic, strong) UIButton *moreButton;
@property (nonatomic, strong) UIButton *lostButton;
@property (nonatomic, strong) UILabel *titleLabel;
@end

@implementation MyCustomCell

- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {
    self = [super initWithStyle:UITableViewCellStyleDefault reuseIdentifier:reuseIdentifier];
    if (self) {

        // BOTTOM LAYER (MORE AND LOST BUTTONS)
        UIButton *aButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [aButton setFrame:CGRectZero];
        [aButton setTitle:@"More" forState:UIControlStateNormal];
        [aButton setTitleShadowColor:[UIColor clearColor] forState:UIControlStateNormal];
        [aButton setBackgroundColor:[UIColor colorWithRed:0.78 green:0.78 blue:0.78 alpha:1.0]];
        [[self contentView] addSubview:aButton];
        [self setMoreButton:aButton];

        aButton = [UIButton buttonWithType:UIButtonTypeCustom];
        [aButton setFrame:CGRectZero];
        [aButton setTitle:@"Lost" forState:UIControlStateNormal];
        [aButton setTitleShadowColor:[UIColor clearColor] forState:UIControlStateNormal];
        [aButton setBackgroundColor:[UIColor colorWithRed:1.00f green:0.23f blue:0.19f alpha:1.00f]];
        [[self contentView] addSubview:aButton];
        [self setLostButton:aButton];

        // TOP LAYER
        UIView *aView = [[UIView alloc] initWithFrame:CGRectZero];
        [aView setBackgroundColor:[UIColor whiteColor]];
        [[self contentView] addSubview:aView];
        [self setTopLayer:aView];

        UIPanGestureRecognizer *aPanRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(panGestureAction:)];
        [aPanRecognizer setMinimumNumberOfTouches:1];
        [aPanRecognizer setMaximumNumberOfTouches:1];
        [aView addGestureRecognizer:aPanRecognizer];

        // title label
        UILabel *aLabel = [[UILabel alloc] initWithFrame:CGRectZero];
        [aView addSubview:aLabel];
        [self setTitleLabel:aLabel];
    }
    return self;
}

- (void)layoutSubviews {

    [super layoutSubviews];

    CGRect bounds = [[self contentView] bounds];
    CGRect frame = CGRectZero;

    // BOTTOM LAYER (MORE AND LOST BUTTONS)
    frame.origin.x = bounds.size.width-(kEditButtonWidth+kEditButtonWidth); // two buttons wide
    frame.size.width = kEditButtonWidth;
    frame.size.height = bounds.size.height;
    [[self moreButton] setFrame:frame];

    frame.origin.x += kEditButtonWidth;
    [[self lostButton] setFrame:frame];

    // TOP LAYER
    frame = bounds;
    CGPoint anchorPoint = CGPointMake(0.0f, [[[self topLayer] layer] anchorPoint].y);
    [[[self topLayer] layer] setAnchorPoint:anchorPoint];
    [[self topLayer] setFrame:frame];

    // title label
    frame.origin.x = 20.0;
    frame.origin.y = 4.0;
    frame.size.width = bounds.size.width-40.0;
    frame.size.height = 21.0;
    [[self titleLabel] setFrame:frame];
}

- (void)panGestureAction:(id)sender {

    // on the first touch, get the center coordinates (x and y) of the view
    CGPoint translatedPoint = [(UIPanGestureRecognizer*)sender translationInView:self];
    if([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateBegan) {
        [self setFirstX:[[sender view] center].x];
        [self setFirstY:[[sender view] center].y];
    }

    // add translated point to reference points
    translatedPoint = CGPointMake([self firstX]+translatedPoint.x, [self firstY]);
    [[sender view] setCenter:translatedPoint];

    // when pan ends (set final x to be either back to zero or showing buttons)
    if ([(UIPanGestureRecognizer*)sender state] == UIGestureRecognizerStateEnded) {
        CGFloat finalX = translatedPoint.x+(0.30*[(UIPanGestureRecognizer*)sender velocityInView:self].x);
        if (finalX < -1.0f*FMEditButtonWidth) {
            finalX = -2.0f*FMEditButtonWidth;
            [self setEditMode:YES];
        } else {
            finalX = 0.0f;
            [self setEditMode:NO];
        }

        // animate view
        [UIView animateWithDuration:1.0 delay:0.0 usingSpringWithDamping:1.0f initialSpringVelocity:1.0f options:UIViewAnimationOptionCurveEaseOut | UIViewAnimationOptionAllowUserInteraction | UIViewAnimationOptionBeginFromCurrentState animations:^{
            [[sender view] setCenter:CGPointMake(finalX, [self firstY])];
        } completion:NULL];
    }
}

@end

希望这会有所帮助。

Answer 2

在layoutSubviews 或willTransitionToState: 中看不到视图的原因是删除按钮视图还不存在或者它还不是视图层次结构的一部分。 为了“看到”它，您需要推迟一点浏览视图层次结构的代码，并允许操作系统同时创建/添加视图：

- (void)willTransitionToState:(UITableViewCellStateMask)state
{
    [super willTransitionToState:state];

    if (state & UITableViewCellStateShowingDeleteConfirmationMask)
    {
        [self performSelector:@selector(findDeleteButtonViewThroughViewHierarchy:) withObject:self.subviews afterDelay:0];
    }
}

请注意，这是一个脆弱的解决方案，因为它基于可能随时更改的 Apple 内部实现。

这里是一个（几乎）完整的例子：

Customizing iOS 7 Delete button

Answer 3

不确定这是否适用于 ios 7，但请看一下：

(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{

  if (editingStyle == UITableViewCellEditingStyleDelete)

   {

    //   Your Code

    }
}