I'm having trouble with creating my UITableViewCell since UITableViewCell : initWithFrame : reuseIdentifier is deprecated. Please stay with me, I've looked over other questions about this but couldn't find them helpful. So here is my function.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyCellObject *cell = (MyCellObject *)[tableView_ dequeueReusableCellWithIdentifier:#"cellid"];
if (cell == nil) {
cell = [[[ChatCell alloc] initWithFrame:CGRectZero reuseIdentifier:#"cellid"] autorelease];
}
return cell;
}
As I read from other questions, I tried:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyCellObject *cell = (MyCellObject *)[tableView_ dequeueReusableCellWithIdentifier:#"cellid"];
if (cell == nil) {
cell = [[[MyCellObject alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cellid"] autorelease];
}
return cell;
}
But my cell won't display its text then. I can tap the cell row and it becomes selects, but no visible text. Because my cell text is handled in my MyCellObject and not cell.textLabel.text, I need to init the cell with a frame (initWithFrame), but I also need to init it with an identifier (reuseIdentifier).
Thanks!
EDIT: I don't think MyCellObject as everything worked before the above function was deprecated. Here's part of MyCellObject and it is derived from UITableViewCell:
- (id)initWithFrame:(CGRect)frame reuseIdentifier:(NSString *)reuseIdentifier {
self = [super initWithFrame:frame reuseIdentifier:reuseIdentifier];
if (self == nil) {
return nil;
}
tagLabel = [[UILabel alloc] initWithFrame:CGRectZero];
tagLabel.backgroundColor = [UIColor clearColor];
tagLabel.font = [UIFont systemFontOfSize:14];
tagLabel.lineBreakMode = UILineBreakModeWordWrap;
tagLabel.opaque = YES;
[self addSubview:tagLabel];
}
The reason I have it setup that was is so I can "micro manage" the text in it a little more.
1) You haven't set the cell title. So you won't see any text on the cell. Here you have used a UITableViewCell class. So you will need to add a label to the cell in the storyboard and set outlet to UITableViewCell in your case which is MyCellObject class. Then you will be able to set text to that label.
2) You can just use
MyCellObject *cell = (MyCellObject *)[tableView dequeueReusableCellWithIdentifier:#"cellid"];
Try this..
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
MyCellObject *cell = (MyCellObject *)[tableView dequeueReusableCellWithIdentifier:#"cellid"];
cell.myCustomLabel.text = #"Your text";
return cell;
}
Related
As a Xcode beginner, I want to display a thumbnail in the table cell in my app. For now, I have this code which parses JSON data and posts it in the title and subtitle of the cell.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"MainCell"];
if(cell == nil){
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"MainCell"];
}
cell.textLabel.text = [[news objectAtIndex:indexPath.row] objectForKey:#"receta"];
cell.detailTextLabel.text = [[news objectAtIndex:indexPath.row] objectForKey:#"koha"];
return cell;
}
How can I show a thumbnail in the right of the cell?
Thanks.
If you don't want to make a custom cell, you can create a UIImageView with your desired image and set it as the cell's accessoryView, which will show it on the right edge of the cell. You also need to ensure that the height of the cell is tall enough to fit the image's height.
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 100;
}
- (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.accessoryView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"some-image-name"]];
return cell;
}
You can return a constant (I chose 100) if the image will always be a fixed size, or you can check the UIImage's size and return something like size.height + 10 for some extra padding.
I want to create a custom tableViewCell programmatically.
This is what I do:
Creating a tableViewCell subclass and importing it to the tableViewController
In the tableViewController m:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
static NSString *CellIdentifier = #"StoreCell";
CustomCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
if (cell == nil) {
cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
return cell;}
In the CustomCell m:
-(id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier
{
self = [super initWithStyle:style reuseIdentifier:reuseIdentifier];
if (self) {
NSLog(#"Hello!");
}
return self;
}
(Sorry for not getting the code highlighting thing to work)
My problem is that the CustomCell don't get initialized. The initWithStyle never gets triggered. I followed a couple of tutorials and they do the exact same thing, but successfully..
With iOS 6, dequeReusableCellWithIdentifier:forIndexPath: always returns a cell, so your if-case never gets called.
If a cell with that identifier is not available, it initializes it itself.
Try implementing initWithCoder: in the UITableViewCell subclass, that's what gets called in that case.
In cellForRowAtIndexPath try this
-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"StoreCell";
CustomCell *cell = (CustomCell*)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[CustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
return cell;
}
I finally figured it out. The cells didn't get initialized because I was using prototypes cells in the storyboard. I set the prototypes cells to 0 and it works :)
This is my first time I am working on UITableView connected to custom delegate and datasource. Until today, I used to connect to "self". The prequel for this question is here.
So, I have two additional UIViews. Using segmented control I put one of the over mentioned UIViews on self.view...
Have created two UITableView subclasses and set them as delegate and datasource. Works fine, no leaks or crashes. Checked if the classes getting initialized on segmentedControl index change:
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
NSLog(#"Nominals got init");
}
return self;
}
NSLog works when changing segment.
The question:
In my custom delegate class I override the methods required by UITableViewDelegate and UITableViewDataSource protocols.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return 20;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
UILabel *lbl=[[UILabel alloc]initWithFrame:CGRectMake(12, 12, 200, 12)];
lbl.text=#"some nominal";
cell.textLabel.text=#"Nominal";
[cell addSubview:lbl];
return cell;
}
At moment I am getting exception:
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'UITableView dataSource must return a cell from tableView:cellForRowAtIndexPath:'
Well, isn't the cell in my custom delegated class is the same cell of my UITableView I've created:
-(void)populateNominals:(int)subCountryID
{
NominalsTableViewDelegate *del=[[NominalsTableViewDelegate alloc]init];
[self setNominalsDelegate:del];
UITableView *nominalsTableView=[[UITableView alloc]initWithFrame:CGRectMake(0, 0, 320, 372) style:UITableViewStylePlain];
[nominalsTableView setDelegate:nominalsDelegate];
[nominalsTableView setDataSource:nominalsDelegate];
[nominalsTableView reloadData];
[self.nominalsView addSubview:nominalsTableView];
}
what's my mistake? Thank you in advance.
You aretrying to dequeue a cell using dequeueReusableCellWithIdentifier. If there is no cell in the queue what happens ? Definitely crash.
So you need to allocate a cell, add this line too:
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil)
{
cell = [[UITableViewCell alloc] init];
}
On your tableView:cellForRowAtIndexPath: method, you are missing the case where there are no cells to be dequeued. Take a look at your code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
UILabel *lbl=[[UILabel alloc]initWithFrame:CGRectMake(12, 12, 200, 12)];
lbl.text=#"some nominal";
cell.textLabel.text=#"Nominal";
[cell addSubview:lbl];
return cell;
}
You should do something like:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (!cell) {
cell = [[UITableViewCell alloc] init];
}
UILabel *lbl=[[UILabel alloc]initWithFrame:CGRectMake(12, 12, 200, 12)];
lbl.text=#"some nominal";
cell.textLabel.text=#"Nominal";
[cell addSubview:lbl];
return cell;
}
because by doing that, if you can't dequeue a cell, you're creating a new one.
the dequeueReusableCellWithIdentifier will return UITableViewCell instances when the cells are being reused while scrolling through the tableView.
So add
if (nil == cell)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
You have to use the initWithStyle:reuseIdentifier: which is the designated initializer for tableview cells.
Okay, I am having another UITableView problem. For some reason the indexPath.row is all jumbled up. When I comment out the if statement that sets up the cell, everything works fine. The NSLogs tell me that they are loading in order, but all the cells are out of order.
It also seems as if they repeat; I only see 8 cells, and they repeat over and over.
Here's my code:
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
NSLog(#"row: %d",indexPath.row);
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.backgroundColor = [UIColor clearColor];
cell.contentView.backgroundColor = [UIColor clearColor];
// Add subviews like this:
// [[cell contentView] addSubview:objectName];
// And I get the row number like this: indexPath.row when getting objects from the array
}
return cell;
}
To use your code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
NSLog(#"row: %d",indexPath.row);
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.backgroundColor = [UIColor clearColor];
cell.contentView.backgroundColor = [UIColor clearColor];
// Add subviews like this:
// [[cell contentView] addSubview:objectName];
}
### Move this here ###
// And I get the row number like this: indexPath.row when getting objects from the array
return cell;
}
" I only see 8 cells, and they repeat over and over." Correct.
What your missing is that that is how it is supposed to work. That's why only if the cell is nil are you alloc & init'ing a new cell. So you alloc and init and set the colors and add subviews in the if statement. Then after the if(cell==nil) you know you have a valid cell to populate with some data according to the indexPath variable passed in.
The problem is that now you are setting up the cell when it is nil and assigning all of the displayed data according to the indexPath passed in. The problem is cell is not nil the second time it's used so the data is never changed.
To address your speed comment further, I'll use an old fallback example.
- (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];
UILabel *hugeLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, cell.frame.size.width, cell.frame.size.height)];
hugeLabel.tag = 300;
[cell addSubview:hugeLabel];
}
[(UILabel *)[cell viewWithTag:300] setText:[arrayOfStrings objectAtIndex:indexPath.row]];
return cell;
}
If you look at the sample above, you'll see that we add a UILabel to the cell setting it's tag to 300. Then after the if statement we will have either a brand new cell or a reused cell with text already in the label. No matter either way we simply change the text of the existing label to whatever it should be considering the row. In this way we avoid creating views over and over.
If you are dead-set on caching your UITableViewCells you could do so like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
if (indexPath.row < _cells.count){
return [_cells objectAtIndex:indexPath.row]; // _cells is an NSMutableArray setup in viewDidLoad
}
UITableViewCell *cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#""];
cell.textLabel.text = [source objectAtIndex:indexPath.row]; // source is an NSArray of NSStrings I set up in viewDidLoad
[_cells addObject:cell];
return cell;
}
Note When running this on device don't be surprised when in the console you see Received memory warning What's efficient & what's easy are often not the same.
The way you have it set up now, cell.selectionStyle, cell.backgroundColor, and cell.contentView.backgrounColor, etc., only get set when if (cell == nil) is true. You need to move that code outside the if statement block, so that it gets called both when dequeueReusableCellWithIdentifier: produces a cell and when it has no cells in inventory and produces nothing (i.e., nil).
when I used layoutSubviews method of UItableViewcell with category, just like the code below
#implementation UITableViewCell (forimage)
- (void)layoutSubviews{
[super layoutSubviews];
self.imageView.frame = CGRectMake(0, 0, 50, 50);
}
#end
when I used the code below to draw the cells , the textLabel was disappeared ,anyone know why it be that~, and does that mean if I use layoutSubviews,I must write all the subviews what I need in the method?
- (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];
}
RadioInfo *radioinfo = [radios objectAtIndex:indexPath.row];
cell.textLabel.text = [NSString stringWithFormat:#"%#",radioinfo._name];
if(!radioinfo._logo){
if(self.tableView.dragging == NO && self.tableView.decelerating == NO){
[self startPicDownload:radioinfo forIndexPath:indexPath];
}
cell.imageView.image = [UIImage imageNamed:#"1.jpg"];
}
else {
cell.imageView.image = radioinfo._logo;
}
return cell;
}
What you want to do is add to the behaviour of UITableViewCell's layoutSubviews method, not replace it.
To properly add to the behaviour, subclass the cell and perform your own layout, as you have above but add a [super layoutSubviews] right at the top of your method to ensure that the cell's own basic layout is performed first.