I have a UIViewController that at some point grows a UITableView, and when it does I simply init the TableView instance variable and add it to the view, but I'm not sure how to handle the dequeueing of cells to add to the view; I need a reuse identifier, but I'm not sure how to set it.
What do I do within this method?
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = #"wot";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];
return cell;
}
Use the method initWithStyle:reuseIdentifier
check if cell exists
If it doesn't, then you need to initialize it.
code
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath (NSIndexPath*)indexPath
{
static NSString *cellIdentifier = #"wot";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];
if (!cell)
cell = [[UITableViewCell alloc] initWithStyle: someStyle reuseIdentifier: cellIdentifier];
return cell;
}
The reuse identifier need not be explicitly defined.In the cellForRowAtIndexPath method the definitions you included in question is enough to work with
for Reference
Eg
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *MyIdentifier = #"MyReuseIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:MyIdentifier]];
}
Region *region = [regions objectAtIndex:indexPath.section];
TimeZoneWrapper *timeZoneWrapper = [region.timeZoneWrappers objectAtIndex:indexPath.row];
cell.textLabel.text = timeZoneWrapper.localeName;
return cell;
}
Related
-(UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:
(NSIndexPath *)indexPath
{
UITableViewCell *cellName=[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell1"];
NSDictionary *contentdict=[innerarray objectAtIndex:indexPath.row];
static NSString *cellidentify=#"cell";
UITableViewCell *cell=[tableView dequeueReusableCellWithIdentifier:cellidentify];
}
this my code every thing is working but the crash appears when i scroll the tableview
even i have given the array value correctly and given the delegate and datasource as self
is there any thing i need to write r change ?????
i am using Xcode 4.5
Try this...may be it help....
-(UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:
(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"] autorelease];
}
NSDictionary *contentdict = [[NSDictionary alloc]init];
if([innerarray count]>0)
{
contentdict =[innerarray objectAtIndex:indexPath.row];
}
// Write your other cell stuff....
return cell;
}
I think it's crashing because you are not returning any cells from the cellForRowAtIndexPath method. Change cellForRowAtIndexPath like:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath;
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"] autorelease];
}
//do something with the cell
return cell;
}
My TableView didn't coloring a cell blue when I click a cell. the InterfaceBuild has
Selection: Single Selection
Show Selection on Touch : YES
And my code in my table view controller is run when I tap the table
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// code
}
EDIT
- (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];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
}
NSString *item = (NSString *)[songList objectAtIndex:indexPath.row];
cell.textLabel.text = item;
return cell;
}
Realized my problem was the following line in my cellForRowIndexPath function
cell.selectionStyle = UITableViewCellSelectionStyleNone;
I am having issues with what I can only imagine is a very simple problem. I am loading a UITableViewController class called LocationViewController from one UIViewController:
LocationViewController *lvc = [[LocationViewController alloc] init];
[self.navigationController pushViewController:lvc animated:true];
In this class I have the 3 following method implemented:
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 3;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"CityCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
cell.textLabel.text = #"Test";
return cell;
}
And I am getting the following error:
UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:'
I have had this error before when transitioning between ViewControllers using the StoryBoard this was because the CellIdentifier was not correct. I have no idea what I am doing wrong. I have tried loading a nib file with this ViewController but that throws the same error.
You have to allocate the cell. use this code.
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
use this code
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}
cell.textLabel.text = #"Test";
return cell;}
dequeueReusableCellWithIdentifier returns nil, if there is no object in the reusable-cell queue. check if cell is nil after calling dequeueReusableCellWithIdentifier, create a new UITableViewCell in that case.
dequeueReusableCellWithIdentifier is a cache of already created UITableViewCells with your identifier "CityCell"
If you use the code below, it tries to get a cell from the cache, and if it can't it will create one and then store it in the cell cache for later use.
You need the cache for large tables, as it drastically improves table performance when scrolling.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *MyIdentifier = #"CityCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:MyIdentifier] autorelease];
}
cell.textLabel.text = #"Test";
return cell;
}
Take a look at the table view programming guide to learn more about this:
Table Programming Guide
I have a UITableView, and i want each cell to be a fixed height at 50px, how can this be done in Xcode4?
Heres my tableview, loaded from XIB file
- (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];
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 50;
}
how to set the style of the TableView to "UITableViewCellStyleSubtitle". so that i can use it to display as sub title in UITABLE
It's not a style of the UITableView, but of the UITableViewCell:
- (UITableViewCell *)tableView:(UITableView *)tableView1 cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView1 dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier] autorelease];
}
... more stuff
return cell;
}