UITableViewCell与自定义单元格中的备用背景颜色 [英] UITableViewCell with alternate background color in customized cells
问题描述
我希望我的UITableViewCells的背景，每显示两个单元格有不同的颜色，但当我向下和向后滚动，他们都得到相同的颜色。如何知道我的单元格具有不同的contentView大小（根据其内容），我可以获得此效果？
I'd like the background to of my UITableViewCells to have a different color every two cells displayed, but when I scroll down and back, they all get the same color. How can I get this effect knowing that my cells have different contentView size (according to their content) ?
#define FONT_SIZE 14.0f
#define CELL_CONTENT_WIDTH 320.0f
#define CELL_CONTENT_MARGIN 20.0f
#define NAME_CELL_HEIGHT 20.0f
#import "CartCell.h"
@implementation CartCell
@synthesize nameLabel = _nameLabel;
@synthesize ingredientsLabel = _ingredientsLabel;
@synthesize myStore;
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
myStore = [Store sharedStore];
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
self.nameLabel = nil;
self.ingredientsLabel = nil;
// SET "NAME" CELL
self.nameLabel = [[UILabel alloc] initWithFrame:CGRectZero];
[self.nameLabel setLineBreakMode:UILineBreakModeWordWrap];
[self.nameLabel setMinimumFontSize:FONT_SIZE];
[self.nameLabel setNumberOfLines:1];
[self.nameLabel setTag:1];
self.nameLabel.font = [UIFont fontWithName:@"Helvetica-Bold" size:18];
[self.nameLabel sizeToFit];
self.nameLabel.backgroundColor = [UIColor clearColor];
[[self contentView] addSubview:self.nameLabel];
// SET "INGREDIENTS" CELL
self.ingredientsLabel = [[UILabel alloc] initWithFrame:CGRectZero];
[self.ingredientsLabel setLineBreakMode:UILineBreakModeWordWrap];
[self.ingredientsLabel setMinimumFontSize:FONT_SIZE];
[self.ingredientsLabel setNumberOfLines:0];
[self.ingredientsLabel setFont:[UIFont systemFontOfSize:FONT_SIZE]];
[self.ingredientsLabel setTag:2];
self.ingredientsLabel.backgroundColor = [UIColor clearColor];
[[self contentView] addSubview:self.ingredientsLabel];
if (myStore.cellBackgroundShouldBeLight == YES) {
NSLog(@"clear [in] ? %@", myStore.cellBackgroundShouldBeLight ? @"Yes" : @"No");
self.contentView.backgroundColor = [[UIColor alloc]initWithRed:87.0/255.0 green:168.0/255.0 blue:229.0/255.0 alpha:1];
myStore.cellBackgroundShouldBeLight = NO;
} else {
NSLog(@"clear [in] ? %@", myStore.cellBackgroundShouldBeLight ? @"Yes" : @"No");
self.contentView.backgroundColor = [[UIColor alloc]initWithRed:187.0/255.0 green:268.0/255.0 blue:229.0/255.0 alpha:1];
myStore.cellBackgroundShouldBeLight = YES;
}
}
return self;
}
- (void)setSelected:(BOOL)selected animated:(BOOL)animated
{
[super setSelected:selected animated:animated];
// Configure the view for the selected state
}
@end
UPDATE：
我知道试图根据建议在cellForRowAtIndexPath中设置它，但我得到相同的结果：第一次滚动下来工作正常，但是然后再次向上滚动细胞背景颜色。
I'm know trying to set it in cellForRowAtIndexPath as it was suggested, but I get the same result: scrolling down worked fine the first time, but then scrolling up again messed up the cells background color.
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = @"CartCell";
CartCell *cell = (CartCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
Recipes *info = [_fetchedResultsController objectAtIndexPath:indexPath];
if (cell == nil)
{
cell = [[CartCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// if (!cell.nameLabel) {
// cell.nameLabel = (UILabel*)[cell viewWithTag:1];
// // cell.nameLabel = (UILabel*)[cell viewWithTag:1];
// }
// if (!cell.ingredientsLabel)
// cell.ingredientsLabel = (UILabel*)[cell viewWithTag:2];
CGSize constraint = CGSizeMake(CELL_CONTENT_WIDTH - (CELL_CONTENT_MARGIN * 2), 20000.0f);
CGSize size = [info.ingredients sizeWithFont:[UIFont systemFontOfSize:FONT_SIZE] constrainedToSize:constraint lineBreakMode:UILineBreakModeWordWrap];
[cell.nameLabel setFrame:CGRectMake(10, 10, CELL_CONTENT_WIDTH - (CELL_CONTENT_MARGIN * 2), NAME_CELL_HEIGHT)];
[cell.ingredientsLabel setFrame:CGRectMake(CELL_CONTENT_MARGIN, CELL_CONTENT_MARGIN + NAME_CELL_HEIGHT, CELL_CONTENT_WIDTH - (CELL_CONTENT_MARGIN * 2), MAX(size.height, 44.0f))];
// SETTING TEXT CONTENT
cell.nameLabel.text = info.name;
cell.ingredientsLabel.text = info.ingredients;
// SETTING BACKGROUND COLOR
// UIView *lab = [[UIView alloc] initWithFrame:cell.frame];
// [lab setBackgroundColor:[UIColor blueColor]];
if (myStore.cellBackgroundShouldBeLight == YES) {
NSLog(@"clear? %@", myStore.cellBackgroundShouldBeLight ? @"Yes" : @"No");
cell.contentView.backgroundColor = [[UIColor alloc]initWithRed:87.0/255.0 green:84.0/255.0 blue:229.0/255.0 alpha:1];
// cell.backgroundView = lab;
// ingredientsLabel.backgroundColor = [UIColor clearColor];
// nameLabel.backgroundColor = [[UIColor alloc]initWithRed:87.0/255.0 green:168.0/255.0 blue:229.0/255.0 alpha:1];
// [cell setBackgroundColor: [[UIColor alloc]initWithRed:87.0/255.0 green:168.0/255.0 blue:229.0/255.0 alpha:1]];
// [cell setBackgroundColor:[UIColor colorWithRed:.8 green:.8 blue:1 alpha:1]];
myStore.cellBackgroundShouldBeLight = NO;
} else {
// cell.contentView.tag = 2;
NSLog(@"clear? %@", myStore.cellBackgroundShouldBeLight ? @"Yes" : @"No");
cell.contentView.backgroundColor = [[UIColor alloc]initWithRed:187.0/255.0 green:184.0/255.0 blue:229.0/255.0 alpha:1];
myStore.cellBackgroundShouldBeLight = YES;
}
return cell;
}
推荐答案
indexPath告诉你你需要知道的一切。如果indexPath.row是偶数，那么使用一种颜色。如果indexPath.row是奇数，则使用不同的颜色。
It is very simple, the indexPath tells you everything you need to know. If the indexPath.row is even then use one color. If the indexPath.row is odd use a different color.
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
…
// SETTING BACKGROUND COLOR
// UIView *lab = [[UIView alloc] initWithFrame:cell.frame];
// [lab setBackgroundColor:[UIColor blueColor]];
if (indexPath.row % 2) {
cell.contentView.backgroundColor = [[[UIColor alloc]initWithRed:87.0/255.0 green:84.0/255.0 blue:229.0/255.0 alpha:1] autorelease];
} else {
cell.contentView.backgroundColor = [[[UIColor alloc]initWithRed:187.0/255.0 green:184.0/255.0 blue:229.0/255.0 alpha:1] autorelease];
}
…
return cell;
}
因为盲目假设细胞将被要求在交替对是一个坏的假设。 tableView可以请求以任何顺序选择单元格。在你的例子中，我相信细胞可能被要求如下。首先，要求0，1，...，9。接下来，向下滚动，并获取10,11和12。此时，0，1和2已经离开屏幕。你向上滚动回来，2被要求，但是不，你的模型是一个奇数交替，所以你得到错误的颜色。
Your method is having problems because blindly assuming cells will be asked for in alternating pairs is a bad assumption. The tableView could ask for cells in any order is chooses. In your example, I believe cells could be asked for as follows. First, 0, 1,…, 9 are asked for. Next, you scroll down and 10, 11, and 12 are fetched. At this point, 0, 1, and 2 have gone off the screen. You scroll back up and 2 is asked for, but oh no, your model is on an odd number alternation, so you get the wrong color.
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