UITableView样式分组中的自定义selectedBackgroundView出站

Question

使用UITableView Style Grouped后，使用带自定义颜色的selectedBackgroundView时会出现问题。

它在那里画UITableViewCell。 是否可以将它们绑定到绑定？

Answer 1

我有类似的问题，没有找到任何简单易行的方法来解决。我为UIImage制作了类别，并使用了几张图片来捕获所有案例。

• single_cell_bg.png - 包含所有圆角的图片
• top_cell_bg - 带圆角顶角的图片
• .....

不那么优雅但正在工作

@interface UIImage (CellBacground)
- (UIImage *)backgroundCellViewforRow:(NSInteger)row totalRow:(NSInteger)total;
@end



#import "UIImage+CellBacground.h"

@implementation UIImage (CellBacground)

- (UIImage *)backgroundCellViewforRow:(NSInteger)row totalRow:(NSInteger)total {
    NSString *path = NULL;
    if (row == 0) {
        if(total == 1) {
            path = [[NSBundle mainBundle] pathForResource:@"single_cell_bg" ofType:@"png"];
        } else {
            path = [[NSBundle mainBundle] pathForResource:@"top_cell_bg" ofType:@"png"];
        }
    } else {
        if ((total - row) == 1) {
            path = [[NSBundle mainBundle] pathForResource:@"bottom_cell_bg" ofType:@"png"];
        } else {
            path = [[NSBundle mainBundle] pathForResource:@"middle_cell_bg" ofType:@"png"];
        }
    }
    UIImage *theImage = [[UIImage alloc] initWithContentsOfFile:path];
    UIEdgeInsets imInset = UIEdgeInsetsMake(10, 10, 10, 10);
    UIImage *strImage = [theImage resizableImageWithCapInsets:imInset];
    return strImage;
}
@end

在tableView中调用：cellForRowAtIndexPath：

UIImage *backImage = [[UIImage alloc] init];
[backImage backgroundCellViewforRow:indexPath.row totalRow:[tableView numberOfRowsInSection:indexPath.section]];
UIImageView *backview = [[UIImageView alloc] initWithImage:backImage];
cell.selectedBackgroundView = backview;

Answer 2

这是一个真正的解决方案，不使用图像，应该适用于所有情况。由于tableView：willDisplayCell：forRowAtIndexPath：仅在iPad上出现问题（见注释），这有点棘手。除此之外，一旦你知道如何围绕个别角落，事情会很自然地落到位。

控制器是圆角的控制器，因为它是知道单元所在位置（第一个，最后一个等）并且影响哪些角被舍入的控制器。进行舍入的最佳位置似乎在tableView：willDisplayCell：forRowAtIndexPath：。以下是UITableViewController子类的示例：

#import "MainViewController.h"
#import <QuartzCore/QuartzCore.h>

@interface CustomCell : UITableViewCell

@end

@implementation CustomCell

- (void)installSelectedBackgroundView {
    UIView *view = [[UIView alloc] initWithFrame:self.frame];
    view.backgroundColor = [UIColor redColor]; // choose a color or add a gradient, etc
    view.layer.borderWidth = 1; // optional border
    view.layer.borderColor = [[UIColor grayColor] CGColor];
    self.selectedBackgroundView = view;
}

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

- (void)awakeFromNib {
    [super awakeFromNib];
    [self installSelectedBackgroundView];
}

@end

@implementation MainViewController

#pragma mark - Table view data source

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    return 3;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    static NSString *CellIdentifier = @"Cell";
    CustomCell *cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    cell.textLabel.text = [NSString stringWithFormat:@"Cell %d", indexPath.row];
    return cell;
}

+ (void)roundCorners:(UIRectCorner)corners forView:(UIView *)view {
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:view.bounds
                                                   byRoundingCorners:corners
                                                         cornerRadii:CGSizeMake(10.0, 10.0)];

    CAShapeLayer *maskLayer = [CAShapeLayer layer];
    maskLayer.frame = view.bounds;
    maskLayer.path = maskPath.CGPath;
    view.layer.mask = maskLayer;
}

+ (void)roundCornersForSelectedBackgroundViewForTableView:(UITableView *)tableView cell:(UITableViewCell *)cell indexPath:(NSIndexPath *)indexPath {
    NSUInteger rows = [tableView numberOfRowsInSection:indexPath.section];
    if (rows == 1) {
        [[self class] roundCorners:UIRectCornerAllCorners forView:cell.selectedBackgroundView];
    } else if (indexPath.row == 0) {
        [[self class] roundCorners:UIRectCornerTopLeft | UIRectCornerTopRight forView:cell.selectedBackgroundView];
    } else if (indexPath.row == rows-1) {
        [[self class] roundCorners:UIRectCornerBottomLeft | UIRectCornerBottomRight forView:cell.selectedBackgroundView];
    } else {
        [[self class] roundCorners:0 forView:cell.selectedBackgroundView];
    }
}

+ (void)deferredRoundCornersForSelectedBackgroundViewForTableView:(UITableView *)tableView cell:(UITableViewCell *)cell indexPath:(NSIndexPath *)indexPath {
    int64_t delayInSeconds = 0;
    dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, delayInSeconds * NSEC_PER_SEC);
    dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
        [[self class] roundCornersForSelectedBackgroundViewForTableView:tableView cell:cell indexPath:indexPath];
    });
}

- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
    // cell.selectedBackgroundView.frame is not sized correctly yet, so rounding the corners has to be deferred briefly
    [[self class] deferredRoundCornersForSelectedBackgroundViewForTableView:tableView cell:cell indexPath:indexPath];
}

@end

Answer 3

UIView * myCellView = [[UIView alloc] initWithFrame：cell.frame];

myCellView.backgroundColor = [UIColor colorWithRed：1 green：1 blue：0.75 alpha：1];

cell.selectedBackgroundView = myCellView;

[myCellView release];