如何在ios中为TableView单元格设置角半径

Question

嗨，我是 iOS 新手，在我的应用程序中我使用的是 TableList，我想将 tableList 单元格角半径设置为 3.0。这是我的代码。它仅在左角而不是所有角上应用圆角半径。

我的代码：-

- (CGFloat)tableView:(UITableView *)aTableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {

    return 75;
}

    - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

        static NSString *simpleTableIdentifier = @"MyCell";

        Cell = (MyTripsCell *)[MaintableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
        if (Cell == nil)
        {
            NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"MyTripsCell" owner:self options:nil];
            Cell = [nib objectAtIndex:0];
        }

        Cell.layer.cornerRadius = 0.0;
        Cell.selectionStyle = UITableViewCellSelectionStyleNone;

        return Cell;
    }


    -(void) tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *) cell forRowAtIndexPath:(NSIndexPath *)indexPath{

        cell.contentView.backgroundColor = [Bg colorWithHexString:@"EEEEEE"];
        UIView * whiteRoundedView = [[UIView alloc]initWithFrame:CGRectMake(0, 12, MaintableView.frame.size.width, 70)];

        whiteRoundedView.layer.backgroundColor = [Bg colorWithHexString:@"FDFDFD"].CGColor;

        whiteRoundedView.layer.masksToBounds = YES;
        whiteRoundedView.layer.cornerRadius = 3.0;
        whiteRoundedView.layer.shadowOffset = CGSizeMake(-1, -1);
        [cell.contentView addSubview:whiteRoundedView];
        [cell.contentView sendSubviewToBack:whiteRoundedView];

        if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {
            [cell setSeparatorInset:UIEdgeInsetsZero];
        }
        if ([cell respondsToSelector:@selector(setPreservesSuperviewLayoutMargins:)]) {
            [cell setPreservesSuperviewLayoutMargins:NO];
        }
        if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {
            [cell setLayoutMargins:UIEdgeInsetsZero];
        }
    }

Answer 1

问题

代码没问题，因为它在每个角落都做圆角半径，但问题是您实际上将视图的原点移动到 y=12。该视图与 tableView 具有相同的宽度，并且它具有角半径，当视图在右侧超出屏幕时，您只是看不到这一点。

解决方案

为了让您的视图位于屏幕中间，您将其中心设置为 contentView 的中心。并使用宽度来设置填充。

您的代码解决方案：

// Using this width and setting the view to the center will give you padding of 12 pixels on left and right
NSInteger width = MaintableView.frame.size.width - 24;
UIView * whiteRoundedView = [[UIView alloc]initWithFrame:CGRectMake(0, 0, width, 70)];
whiteRoundedView.center = cell.contentView.center;

whiteRoundedView.layer.backgroundColor = [Bg colorWithHexString:@"FDFDFD"].CGColor;

whiteRoundedView.layer.masksToBounds = YES;
whiteRoundedView.layer.cornerRadius = 3.0;
whiteRoundedView.layer.shadowOffset = CGSizeMake(-1, -1);
[cell.contentView addSubview:whiteRoundedView];
[cell.contentView sendSubviewToBack:whiteRoundedView];

if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {
    [cell setSeparatorInset:UIEdgeInsetsZero];
}
if ([cell respondsToSelector:@selector(setPreservesSuperviewLayoutMargins:)]) {
    [cell setPreservesSuperviewLayoutMargins:NO];
}
if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {
    [cell setLayoutMargins:UIEdgeInsetsZero];
}

无论如何，我可以通过在每次出列单元格时不添加该视图来对该代码进行一些改进。另请注意，为此视图设置maskToBounds = YES，将导致您的阴影不显示（请参阅here）

我的代码解决方案（已编辑）

UIView *roundedView = [cell.contentView viewWithTag:100];
if (roundedView == nil) {
    // Add some padding to the view in order to see the shadow
    NSInteger spacingBothHorizontal = 2;
    CGRect customizedFrame = CGRectMake(spacingBothHorizontal/2, 0, CGRectGetWidth(cell.contentView.frame) - spacingBothHorizontal, CGRectGetHeight(cell.contentView.frame) - 20);
    roundedView = [[UIView alloc] initWithFrame:customizedFrame];
    
    // Layer customizations
    roundedView.layer.cornerRadius = 10.0f;
    roundedView.backgroundColor = [UIColor redColor];
    roundedView.layer.shadowOffset = CGSizeMake(-1, -1);
    roundedView.layer.shadowOpacity = 2.0;
    roundedView.layer.shadowColor = [UIColor blueColor].CGColor;
    roundedView.tag = 100;
    
    if ([cell respondsToSelector:@selector(setSeparatorInset:)]) {
        [cell setSeparatorInset:UIEdgeInsetsZero];
    }
    if ([cell respondsToSelector:@selector(setPreservesSuperviewLayoutMargins:)]) {
        [cell setPreservesSuperviewLayoutMargins:NO];
    }
    if ([cell respondsToSelector:@selector(setLayoutMargins:)]) {
        [cell setLayoutMargins:UIEdgeInsetsZero];
    }
    
    // Add it to view
    [cell.contentView addSubview:roundedView];
    [cell.contentView sendSubviewToBack:roundedView];
    cell.contentView.backgroundColor = [UIColor blackColor];
}

结果

Answer 2

这是示例代码。 这是您要找的吗？

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return 20;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:@"UITableViewCell"];
    if (cell == nil)
    {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"UITableViewCell"];
    }
    if ([cell viewWithTag:100] == nil)
    {
        UIView* roundedView = [[UIView alloc]initWithFrame:CGRectInset(cell.bounds, 2, 2)];
        roundedView.backgroundColor = [UIColor lightGrayColor];
        roundedView.tag = 100;
        roundedView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
        [cell insertSubview:roundedView atIndex:0];
        roundedView.layer.cornerRadius = 5;
        roundedView.layer.masksToBounds = true;
    }

    return cell;
}

在你的情况下，使用以下并删除 willdisplaycell

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {

    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    if (cell == nil) {

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];

    }
    if ([cell viewWithTag:100] == nil)
    {
        UIView* roundedView = [[UIView alloc]initWithFrame:CGRectInset(cell.bounds, 2, 2)];
        roundedView.backgroundColor = [UIColor lightGrayColor];
        roundedView.tag = 100;
        roundedView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
        [cell insertSubview:roundedView atIndex:0];
        roundedView.layer.cornerRadius = 5;
        roundedView.layer.masksToBounds = true;
    }
    cell.textLabel.text = @"Hello world";

    return cell;
}

- (CGFloat)tableView:(UITableView *)aTableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {

    return 75;
}

Answer 3

可能的原因是：

你的单元格高度是 75。你正在写这个：

UIView * whiteRoundedView = [[UIView alloc]initWithFrame:CGRectMake(0, 12, MaintableView.frame.size.width, 70)];

查看实际CGRectMake

CGRect CGRectMake ( CGFloat x, CGFloat y, CGFloat width, CGFloat height );

在您的情况下，y = 12。根据单元格的坐标，它是超级视图的 (0,0,width,height)，当您放置 (0, 12, width, height) 的子视图（您的 whiteRoundedView ）时，其下部将不会显示。作为其超出单元格的视口。试着理解这些坐标系。

编辑：

将您的视图代码更改为：

UIView * whiteRoundedView = [[UIView alloc]initWithFrame:CGRectMake(0, 3, cell.frame.size.width, 69)];

并将圆角半径设置为 10。

whiteRoundedView.layer.cornerRadius = 10.0;

运行应用程序并查看差异。