I have a UIImageView inside a custom cell. If there is no image to display in cell then cell height should automatically decrease.(ImageView Height should be zero in that case). How to specify constraint for this in xib ?
Your UITableView data source should represent the existence of this image.
You should use the following delegate method:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
if (self.dataSource[indexPath.rox].imageExists) {
return 50.0; // Change to your value with image
}
return 10.0; // Change to your value without image
}
Your UITableViewDelegate should implement tableView:heightForRowAtIndexPath:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
// add your condition here if image exit or not and set cell size dynamically
return [indexPath row] * 20;
}
You will probably want to use NSString's sizeWithFont:constrainedToSize:lineBreakMode: method to calculate your row height rather than just performing some silly math on the indexPath.
Here is good sample code for dynamic size cell.
Related
I am new to iOS. I have implemented a table view which is populated with array values successfully, but I'm not satisfied with the result. When I scroll my table view the top values are hiding.
Here is my problem: based on the cell height the table view height should also get increased dynamically in UITableview. How can I accomplish that?
For UITableViewCell dynamic height you can use following delegate by return UITableViewAutomaticDimension
-(CGFloat)tableView:(UITableView *)tableView estimatedHeightForRowAtIndexPath:(NSIndexPath *)indexPath{
return 300; //give maximum heigh you want
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath{
return UITableViewAutomaticDimension;
}
and to increase tableview height based on content size use the below line of code
YOUR_TABLE_VIEW_HEIGHT_CONSTRAINT.constant = [YOUR_TABLE_VIEW contentSize].height;
Hope this will help you
I'm trying to create detail view controller as a list of information and I think it would be nice and clean to present this with a static UITableView. But after that it came to my mind that on some level it might be difficult, so please resolve my doubts!
Every UITableViewCell has different style (some are custom, some are basic and few are right-detailed etc.).
What is more, content size of each cell may vary as I have long names put inside labels so they use autolayout to fit.
There is no problem when I have the same cells repeating but with different tex inside UILabels. In that case I use a simple:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (!self.prototypeCell) {
self.prototypeCell = [self.tableView dequeueReusableCellWithIdentifier:#"ActivityCell"];
}
[self fetchedResultsController:[self fetchedResultsController] configureCell:self.prototypeCell atIndexPath:indexPath];
CGSize size = [self.prototypeCell.contentView systemLayoutSizeFittingSize:UILayoutFittingCompressedSize];
return size.height;
}
I don't know how to deal with heightForRowAtIndexPath. I can give an identifier to each cell, call cellForRowAtIndexPath:, and make a big switch or if statement, but is it right? The same problem occurs while I think of cellForRowAtIndexPath: and populating those UITableViewCells. With those testing statements this code won't be pretty and readable.
Any ideas on that case?
In the delegate function of the table view named heightForRowAtIndexPath try to calculate the height for each row and then return it.
//return height for row
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if(tableView==tblLanguage)
{
//Here calculate the dynamic height according to songs count for specific language
return (([[arrSongListForSpecificLanguage objectAtIndex:indexPath.row] count]*40)+40);
}
return 40.0;
}
Im trying to make some of my cells bigger in height. i tried using
CGRect rect = cell.frame;
NSLog(#"before height: %f",rect.size.height);
rect.size.height +=20;
cell.frame = rect;
NSLog(#"AFTER height: %f",cell.frame.size.height);
in
cellForRowAtIndexPath
and
willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath
*)indexPath
The log shows that the values have changed but it doesnt show any change in the simulator.
Thanks for the help
use tableView:heightForRowAtIndexPath method.
Apple docs clearly explains what to do. UITableView class reference
Every tableView has a delegate property.Set it to your viewController and implement above method. Its signature is
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
So, based on indexPath, return whatever the height you desire.
If you want constant height for all rows, you can use rowHeight property of UITableView.
Use heightForRowAtIndexPath of UITableViewDelegate. Example:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return indexPath.row == _pages.count - 1 ? 408 : 450;
}
To make some cells bigger, you should implement the method tableView:heightForRowAtIndexPath:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (<SOMETHING>) {
return height1;
} else {
return height2;
}
}
tableView:cellForRowAtIndexPath: is for configuring the content of the cell that the tableView needs to display.
Note that tableView:heightForRowAtIndexPath: has performance implications if you have a really large table (1000+ entries), this method is called on every row when the table view displays.
I've designed a custom table cell as follows:
However, it is rendering as follows:
as you see, the second label is going in the next cell. Any idea how can I solve this issue and make the cell appear as I designed it?
You need to implement UITableViewDelegate
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
This method:
Asks the delegate for the height to use for a row in a specified
location.
Give a minimum height for each row here. Also if different row have different height according to the content, you have to calculate the height according to the content in that case. Something like this:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
NSString *stringText=[array objectAtIndex: indexPath.row];
CGSize size = [stringText sizeWithFont:[UIFont fontWithName: "yourFont" size: fontSize] constrainedToSize:maxCGSize];
return labelSize.height + padding;
}
I adjust the height of a custom UITableViewCell inside the custom class, and I believe I need to use the -tableView:cellForRowAtIndexPath: method to adjust the height of the cell. I am attempting to just adjust the height of the custom cell in the custom cell class, then grab the cell at the given index path cast it, and return the height of that cell like this:
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath;
{
CustomUITableViewCell *cell = (CustomUITableViewCell *)[tableView cellForRowAtIndexPath:indexPath];
return cell.frame.size.height;
}
But I am getting stack overflow. What is a better way around doing this?
The table view delegate will first call heightForRowAtIndexPath: and then the datasource will construct the cell in cellForRowAtIndexPath: after that based on the computed information.
Therefore your approach will not work.
You need to have some logic for computing the height. (E.g. if you are displaying text the height might be dynamic and depend on the amount of text - you could calculate that with an NSString method.)
If you are just displaying a few types of cells with fixed heights, simply define these heights as constants and return the correct height based on the same logic you have in cellForRowAtIndexPath: to decide which cell to use.
#define kBasicCellHeight 50
#define kAdvancedCellHeight 100
- (CGFloat)tableView:(UITableView *)tableView
heightForRowAtIndexPath:(NSIndexPath *)indexPath {
if (needToUseBasicCellAtThisIndexPath) {
return kBasicCellHeight;
}
return kAdvancedCellHeight;
}
If it's a storyboard cell, you can call dequeueReusableCellWithIdentifier:. Otherwise, you can just instantiate the cell directly with something like [CustomUITableViewCell alloc] initWithFrame:].
I use this approach (using a prototype cell to calculate height) myself because it allows our designer to modify storyboard cells without requiring code changes.
You may want to adjust your approach based on whether the height is static or dynamic as discussed here.