问题
I want to expand the cell size after clicking a seeMoreBtn on cell.
The label and cells have varying length, but their is a constraint in size of label.
When a status is too big, I added a seeMoreBtn, after clicking on see more the remaining text will be shown below, then how to increase the label and cell size.
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath;
{
NSString *text = [items objectAtIndex:[indexPath row]];
CGSize constraint = CGSizeMake(300.0f, 150.0f);
CGSize size = [text sizeWithFont:[UIFont systemFontOfSize:14.0f] constrainedToSize:constraint lineBreakMode:NSLineBreakByCharWrapping];
CGFloat height1 = MAX(size.height, 44.0f);
return height1 + (40.0f);
}
- (UITableViewCell *)tableView:(UITableView *)tv cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *CellIdentifier = [NSString stringWithFormat:@"Cell-%d",indexPath.row];
cell=[tv dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
int lbltag = 1000;
label=[[UILabel alloc]initWithFrame:CGRectZero];
[label setLineBreakMode:NSLineBreakByWordWrapping];
[label setMinimumScaleFactor:14.0f];
[label setNumberOfLines:0];
[label setFont:[UIFont systemFontOfSize:14.0f]];
NSString *text = [items objectAtIndex:[indexPath row]];
[label setText:text];
label.tag = lbltag;
[cell addSubview:label];
CGSize constraint1=CGSizeMake(300.0f, 150.0f);
CGSize size1=[text sizeWithFont:[UIFont systemFontOfSize:14.0f] constrainedToSize:constraint1 lineBreakMode:NSLineBreakByWordWrapping];
[label setFrame:CGRectMake(10.0f, 10.0f, 300.0f, MAX(size1.height, 44.0f))];
int countText=text.length;
if (countText>=350) {
seeMoreBtn=[UIButton buttonWithType:UIButtonTypeRoundedRect];
[seeMoreBtn setTitle:@"See More" forState:UIControlStateNormal];
seeMoreBtn.frame=CGRectMake(220.0f, MAX(size1.height, 44.0f)-10, 80.0f, 20.0f);
seeMoreBtn.tag=indexPath.row ;
[seeMoreBtn addTarget:self action:@selector(increaseSize:) forControlEvents:UIControlEventTouchUpInside];
[cell addSubview:seeMoreBtn];
}
return cell;
}
-(void)increaseSize:(UIButton *)sender{
//What to write here that can adjust the label and cell size
}
回答1:
It would be better, if you subclass the UITableViewCell and use the layoutSubviews to adjust when you adjust the size of the cell.
//In SMTableViewCell.h
@interface SMTableViewCell : UITableViewCell
@property (weak, nonatomic) IBOutlet UILabel *statusLabel;
@property (weak, nonatomic) IBOutlet UIButton *seeMoreButton;
//SMTableViewCell.m
- (void)layoutSubviews
{
CGRect labelFrame = self.statusLabel.frame;
labelFrame.size.height = self.frame.size.height - 55.0f;
self.statusLabel.frame = labelFrame;
CGRect buttonFrame = self.seeMoreButton.frame;
buttonFrame.origin.y = labelFrame.origin.y+labelFrame.size.height+10.0f;
self.seeMoreButton.frame = buttonFrame;
}
Keep an array to store the selectedIndexPaths:
@property (nonatomic, strong) NSMutableArray *selectedIndexPaths;
Calculate the height of the cell:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath;
{
BOOL isSelected = [self.selectedIndexPaths containsObject:indexPath];
CGFloat maxHeight = MAXFLOAT;
CGFloat minHeight = 40.0f;
CGFloat constrainHeight = isSelected?maxHeight:minHeight;
CGFloat constrainWidth = tableView.frame.size.width - 20.0f;
NSString *text = self.items[indexPath.row];
CGSize constrainSize = CGSizeMake(constrainWidth, constrainHeight);
CGSize labelSize = [text sizeWithFont:[UIFont systemFontOfSize:15.0f]
constrainedToSize:constrainSize
lineBreakMode:NSLineBreakByCharWrapping];
return MAX(labelSize.height+75, 100.0f);
}
Initialize custom Show more TableViewCell:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = @"CellIdentifier";
SMTableViewCell *cell= (SMTableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil)
{
cell = [[[NSBundle mainBundle]loadNibNamed:NSStringFromClass([SMTableViewCell class])
owner:nil
options:nil] lastObject];
}
BOOL isSelected = [self.selectedIndexPaths containsObject:indexPath];
cell.statusLabel.numberOfLines = isSelected?0:2;
NSString *text = self.items[indexPath.row];
cell.statusLabel.text = text;
NSString *buttonTitle = isSelected?@"See Less":@"See More";
[cell.seeMoreButton setTitle:buttonTitle forState:UIControlStateNormal];
[cell.seeMoreButton addTarget:self action:@selector(seeMoreButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
[cell.seeMoreButton setTag:indexPath.row];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
return cell;
}
Button click event method:
- (void)seeMoreButtonPressed:(UIButton *)button
{
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:button.tag inSection:0];
[self addOrRemoveSelectedIndexPath:indexPath];
}
- (void)addOrRemoveSelectedIndexPath:(NSIndexPath *)indexPath
{
if (!self.selectedIndexPaths) {
self.selectedIndexPaths = [NSMutableArray new];
}
BOOL containsIndexPath = [self.selectedIndexPaths containsObject:indexPath];
if (containsIndexPath) {
[self.selectedIndexPaths removeObject:indexPath];
}else{
[self.selectedIndexPaths addObject:indexPath];
}
[self.tableView reloadRowsAtIndexPaths:@[indexPath]
withRowAnimation:UITableViewRowAnimationFade];
}
Same Event is given if the cell is selected:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView deselectRowAtIndexPath:indexPath animated:YES];
[self addOrRemoveSelectedIndexPath:indexPath];
}
Sample Demo project link.
回答2:
Add a property like:
@property(strong, nonatomic) NSArray *enlargedIndexPaths;
Initialize it to an empty array. Implement the table view delegate:
- (CGFloat)tableView:(UITableView*)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return ([self.enlargedIndexPaths containsObject:indexPath])? 88.0 : 44.0;
}
Then in increaseSize:
UITableViewCell *cell = sender.superview;
NSIndexPath *indexPath = [self.tableView indexPathFoCell:cell];
[self.enlargedIndexPaths addObject:indexPath];
// do you want to enlarge more than one at a time? You can remove index paths
// here, too. Just reload them below
[self.tableView beginUpdates];
[self.tableView reloadRowsAtIndexPaths:self.enlargedIndexPaths] withRowAnimation:UITableViewRowAnimationTop];
[self.tableView endUpdates];
回答3:
Well, the idea is to change the cells height, based on a value you set for the cell. You can have an NSArray, where you just mark for all cells a value: isExpanded (true or false).
To recap, create an NSMutableArray that will store the cell state (expanded or not):
NSMutableArray *cellState;
init the array and fill it with zeros for all your UITableView items Array. When the cell is expanded, set the cellState objectAtIndex value from 0 to 1 (marking it as expanded).
Then reload that cell:
[self.tableView reloadRowsAtIndexPaths:[NSArray arrayWithObject:[NSIndexPath indexPathForRow:indexPath.row inSection:indexPath.section]] withRowAnimation:UITableViewRowAnimationFade];
and modify the - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath; function to return a bigger value if the cell is expanded...
That's it!
来源：https://stackoverflow.com/questions/15585053/how-to-increase-the-label-and-cell-size-on-clicking-a-button-in-a-tableviewcell