I tried the code below, but the output is always 0.000000:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"CellNotification";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
cell.textLabel.text = #"Test Test Test. I am a cell.";
NSLog(#"%f", cell.textLabel.frame.size.width);
return cell;
}
How can I know what the width of a default UITableViewCell is? I need this information because I have to set the height for UITableViewCell in
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
The width of the cell will be the width of the table, unless your table is grouped, in which case it is slightly smaller.
However, you probably want the width of whatever label you are using to display the text rather than the cell itself.
A further warning is that the heightForRow... method is called for every row in the table before any cells are created, so you may have to use a known value instead.
The NSLog you are using above is asking for the width of the textLabel within the cell, not the actual cell.
NSLog(#"%f",cell.frame.size.width);
Additionally, if you aren't using the grouped table style, the cells width should return the same as the width of the table.
EDIT: I'm not really sure if this was the question, but if you're asking how to set the width of your cells, you don't have to. This is handled for you.
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {
NSLog(#"%#",NSStringFromCGRect(cell.textLabel.frame));
}
EDIT 2:
Try changing this:
if (cell == nil)
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
cell.textLabel.text = #"Test Test Test. I am a cell.";
To this:
if (cell == nil){
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
}
cell.textLabel.text = #"Test Test Test. I am a cell.";
I think you should test your textLabel width in:
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath
Related
I am using UItableViewController and I add label to the cell programatically , the label reads data from json array , on scrolling the cell reuse and the label data change ,
there is any way to prevent this issue ?
Your question is not clear.!! but according to your problem you might not set proper value(array count) for
-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
and find the exact index in array using "indexPath.row"
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
if you provide your code what you've written may help us to re correct it
use following way :
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *CellId = [NSString stringWithFormat:#"CellId%d%d",indexPath.row,indexPath.section];
if (!cell)
{
cell = [[[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellId] autorelease];
}
return cell;
}
Dont use this like of code.It is used to reload the data.
cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellId];
I have a table with a few rows, and the place holder text for all is the same. How can I programmatically change the placeholder text of only the first one?
Thanks!
You need to run an if statement to check the index of the cell. 0 is the first index, so you would need to check to see if the row is 0.
- (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] autorelease];
}
if (indexPath.row == 0)
cell.textLabel.text = #"First Cell";
else
cell.textLabel.text = #"Not First Cell";
}
In order to access your cell AFTER the cell was created/reused, try the - (UITableViewCell *)cellForRowAtIndexPath:(NSIndexPath *)indexPath method of your uitableview object! See the following Apple doc for a detailed elaboration on this method.
Note:
Return Value
An object representing a cell of the table or nil if the cell is not
visible or indexPath is out of range.
I have seen other questions on here related to this, but I have their solutions in place, and things still move around when I scroll.
Basically, I have a table of data and I want the first and only the first row to have a UITableViewCellAccessoryDisclosureIndicator. The problem is, when I scroll around, the indicator duplicates, deletes, and moves to other cells. Here is my code..
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = (UITableViewCell *) [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil){
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
if(indexPath.row == 0) {
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
}
cell.textLabel.text = [tabledata objectAtIndex:indexPath.row];
return cell;
}
The problem is something with the indexPath.row variable.. its somehow returning 0 in other cells that aren't the very first (when it comes to displaying cells). HOWEVER... the data is always right from my array(which implies the value HAS to be correct) and in my
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath{
method, i only wish to change screens when row 0 is clicked.. and regardless of where I have scrolled to, no cells trigger except the very first. So it seems THAT check is always correct while the one inside cellForRowAtIndexPath is not...
Most likely, you are re-using cells that already have the accessoryType set. You need to explicitly set it to NOT show on cells where it shouldn't.
if(indexPath.row == 0){
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
} else {
cell.accessoryType = UITableViewCellAccessoryNone;
}
I have been trying to figure out how to set the accessoryType to UITableViewCellAccessoryCheckmark when the cell is selected but am having trouble finding a decent example of this.
If you know how to do this or a good tutorial could you please let me know that would be great.
To restrict the user to just one selection, meaning to create an exclusive list of one choice only, you could follow these steps;
Firstly, have a global index path declared in your .h file to keep track of the already selected cell ->
NSIndexPath *oldIndexPath;
When you create the cells, be sure to set the accessory type to none, so that no cell is selected by default when the table is seen;
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"CellIdentifier"];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"CallIdentifier"];
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
Finally, in the didSelectRowAtIndexPath delegate method, add the following code which will remove the checkmark from the already selected cell, and add a checkmark to the newly selected one.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if (oldIndexPath==nil) { // No selection made yet
oldIndexPath=indexPath;
[cell setAccessoryType:UITableViewCellAccessoryCheckmark];
}
else {
UITableViewCell *formerSelectedcell = [tableView cellForRowAtIndexPath:oldIndexPath]; // finding the already selected cell
[formerSelectedcell setAccessoryType:UITableViewCellAccessoryNone];
[cell setAccessoryType:UITableViewCellAccessoryCheckmark]; // 'select' the new cell
oldIndexPath=indexPath;
}
}
Hope this works out! :)
Something like this may work:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [self tableView:myTableView cellForRowAtIndexPath:indexPath];
[cell setAccessoryType:UITableViewCellAccessoryCheckmark];
}
To answer the comment below, just push a viewController in the same method like this:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [self tableView:myTableView cellForRowAtIndexPath:indexPath];
[cell setAccessoryType:UITableViewCellAccessoryCheckmark];
// Then push a new view
iPhoneCustomViewController *myVC = [[iPhoneCustomViewController alloc] initWithNibName:#"iPhoneCustomViewController" bundle:nil];
[self.navigationController pushViewController:myVC animated:YES];
[myVC release];
// And deselect the row (if desired)
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
Did you know that:
1.) UITableView keeps track of the index paths for the rows that have been selected? It's in an array called indexPathsForSelectedRows
2.) UITableView has a flag you can set to make it either single or multiple selection. You can change it by calling the setter setAllowsMultipleSelection:(BOOL).
So, assuming that the table has been set to single selection, we can do the following in the tableView:CellForRowAtIndexPath method ...
-(UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *simpleTableIdentifier = #"CellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:simpleTableIdentifier];
}
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
[[cell textLabel] setText:#"Some Text"];
NSArray *selectedIndexPaths = [tableView indexPathsForSelectedRows];
if ([selectedIndexPaths containsObject:indexPath]) {
[cell setAccessoryType:UITableViewCellAccessoryCheckmark];
}else{
[cell setAccessoryType:UITableViewCellAccessoryNone];
}
return cell;}
This implementation of CellForRowAtIndexPath will give you a clean checkmark with no gray background when a cell is selected. You will need to set the checkmark in the didSelectRowAtIndexPath delegate method to make sure a cell gets the checkmark the moment it gets selected.
No need to create separate ivars or anything else to keep track of what was or wasn't selected. It's all neatly contained in the UITableView as Apple intended.
UITableViewCell *newCell = [tableView cellForRowAtIndexPath:indexPath];
newCell.accessoryType=UITableViewCellAccessoryCheckmark;
Implement this in didSelectRowAtIndexPath delegate method
From the docs:
The delegate handles selections in this method. One of the things it
can do is exclusively assign the check-mark image
(UITableViewCellAccessoryCheckmark) to one row in a section
(radio-list style). This method isn’t called when the editing property
of the table is set to YES (that is, the table view is in editing
mode). See "Managing Selections" in Table View Programming Guide for
iOS for further information (and code examples) related to this
method.
Here is an example:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath]
cell.UITableViewAccessoryType = UITableViewCellAccessoryCheckmark;
}
I have a strange problem with my UITableView. I want all the cells in the table to be selectable, such that if a cell is selected, an appropriate action is executed. All the cells in my table are currently selectable apart from the cell at row 0 (the cell at that appears at the top of the table). This cell is not selectable, even though it has been set to allow for selection. Any ideas?
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
tableView.allowsSelection = YES;
static NSString *SettingsTableID = #"SettingsTableID";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:SettingsTableID];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1
reuseIdentifier: SettingsTableID] autorelease];
}
cell.textLabel.text = [tableHeadingsArray objectAtIndex:row];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
Many thanks.
Sorry everyone, I'm being stupid. :) This code was in my ViewController sub-class. I copied the class from an example, and forgot to check it over thoroughly before using it.
-(NSIndexPath *)tableView:(UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath{
NSUInteger row = [indexPath row];
if (row == 0)
return nil;
return indexPath;
}
Deleting this has fixed the problem.
Cheers.