如何在iOS中為TableView單元設置角半徑

Question

嗨，我是iOS的新手，在我的應用程序中，我正在使用TableList，並且我想將tableList單元角的半徑設置為3.0。 這是我的代碼。 它僅在左角而不是所有角上應用角半徑。

我的代碼：

- (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

問題

該代碼是可行的，因為它在每個拐角處都執行拐角半徑，但是問題是您實際上是在將視圖的原點移動到y = 12 。 視圖的寬度與tableView的寬度相同，並且它的拐角半徑是您在視圖超出屏幕右側時看不到的。

解

為了使視圖位於屏幕中間，請將其中心設置為contentView的中心。 並與寬度一起設置填充。

您的代碼解決方案：

// 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];
}

無論如何，我可以通過在每次單元出隊時不添加視圖來對代碼進行一些改進。 還要注意，為此視圖設置maskToBounds = YES會導致您的陰影不顯示（請參閱此處 ）

我的代碼解決方案（已編輯）

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];
}

結果

Answer 2

可能的原因可能是：

您的單元格高度為75。您正在編寫以下代碼：

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

查看實際的CGRectMake

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

在您的情況下y =12。當您放置一個子視圖（您的whiteRoundedView ）為（ whiteRoundedView (0,0,width,height)時(0,0,width,height)它是根據單元格坐標的whiteRoundedView視圖(0,0,width,height) ，它的下部將不顯示。 由於其出了單元格視口。 嘗試了解這些坐標系。

編輯：

將您的查看代碼更改為此：

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

並將角半徑設置為10。

whiteRoundedView.layer.cornerRadius = 10.0;

運行該應用程序，看看有什么不同。

Answer 3

這是示例代碼。 這是您要找的嗎？

- (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;
}

在您的情況下，請使用以下命令並刪除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;
}