As I scroll up and down the table view the data in each cell becomes duplicated and unreadable. Does anyone have any suggestions for the below?
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateStyle:NSDateFormatterShortStyle];
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
UILabel *label1 = [[UILabel alloc]initWithFrame:CGRectMake(10, 12, 250, 20)];
UILabel *label2 = [[UILabel alloc]initWithFrame:CGRectMake(250, 12, 50, 20)];
label1.tag= 666;
label2.tag= 666;
[cell.contentView addSubview:label1];
[cell.contentView addSubview:label2];
// Configure the cell...
President *p = (President *)[self.importedRows objectAtIndex:indexPath.row];
label1.text = p.no;
label2.text = p.name;
UILabel* cellLabel = (UILabel*)[cell viewWithTag: 666];
cellLabel.text = [NSString stringWithFormat:p.no , p.name];
return cell;
}
dequeueReusableCellWithIdentifier caches the generated cells. So if you request a cell which you already created before this cell will NOT be generated again from scratch (meaning that the labels you added before already exists!).
So when adding the labels tag them with a unique number :
label1.tag= 666;
label2.tag= 667;
And before adding them to the cell remove them as follows :
UIView *labelView = [cell.contentView viewForTag:666];
if (labelView != nil) {
[labelView removeFromSuperView];
}
And do the same with the second label.
because you are adding label1 and label2 again and again to cell.
UILabel *label1 = [[UILabel alloc]initWithFrame:CGRectMake(10, 12, 250, 20)];
UILabel *label2 = [[UILabel alloc]initWithFrame:CGRectMake(250, 12, 50, 20)];
[cell.contentView addSubview:label1];
[cell.contentView addSubview:label2];
As the cell is reused, same cell is used for another row, and it already has label1,2. but you are creating label1,2 again and again and adding them to it.
Give different tags for label1,label2.Check if viewWithTag:666 and 667 is present.If not present add them as subview ,if already present, just get them using viewWithTag and change their text values.
The problem here is with below code:
UILabel* cellLabel = (UILabel*)[cell viewWithTag: 666];
cellLabel.text = [NSString stringWithFormat:p.no , p.name];
I have tried your code, commenting these two lines stop overlapping. You can try to change the frame of this label.
I suggest making your own subclass of UITableViewCell which has two UILabel's on it, then in the method you're using above, create instances of your subclass rather than UITableViewCell if the cell doesn't exist, then populate the labels.
In your custom cell implementation file, you'll have to override the 'prepareForReuse' method, and in it set the text of your labels to nil (#""). This properly uses the 'dequeueWithReuseIdentifier' functionality and only creates the labels when necessary, rather than only showing them when required.
A solution where you can gain performance is the following.
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (!cell) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
// create and add labels to the contentView
}
// retrieve and update the labels
Obviously you could also create your UITableViewCell subclass.
You could also try this swag (fresh answer, get your fresh answer!):
BOOL doesContain = [cell.subviews containsObject:imageView];
if (!doesContain)
{
[cell.contentView addSubview:imageView];
}
imageView.image = yourImage];
Also for a quick way to subclass all of your stuff, check my answer.
Related
Hi i am a newbie to iOS.
I have implemented a tableview in ViewController1.In the tableview i am displaying tittle,detailText and disclosure indicator for the cell.
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *MyIdentifier = #"MyIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:MyIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1
reuseIdentifier:MyIdentifier];
}
cell.textLabel.text =[listTableArray objectAtIndex:indexPath.row];
cell.textLabel.textColor=[UIColor grayColor];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
cell.detailTextLabel.text=#"4mile";
return cell;
}
Everything works fine,Now i need a image before the disclosure indicator when i do it with
UIImageView *accessoryView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];
accessoryView.image=[UIImage imageNamed:#"list.png"];
cell.accessoryView = accessoryView;
Disclosure indicator is replaced by the image.But i need both image along with disclosure indicator without using Custom cell.
How can i do it...? Help me out.
Thanks
similiar to the due date but at the place of time i need image
UITableViewCell have a fixed layout, depending on the style you use when you initialize it. You cannot change that layout, since the cell lays out its subviews as it prefers to have them.
add the - (void)layoutSubviews to your cell subclass like this:
- (void)layoutSubviews {
[super layoutSubviews];
self.imageView.frame = CGRectMake(0.0f , 0.0f, 20.0f, 20.0f);
}
else try this
UIImageView *imageView = [[UIImageView alloc] init];
imageView.image = [UIImage imageNamed:#"list.png"];;
[imageView setFrame:CGRectMake(50, 5, 20, 20)]; // customize the frame
[cell.contentView addSubview:imageView];
If you wanna add UIImageView to standard UITableViewCell you need add your imageView to contentView of cell and add all subviews like a textLabel, detailTextLabel and accessoryView
UIImageView *accessoryImageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 20, 20)];
accessoryImageView.image=[UIImage imageNamed:#"list.png"];
[cell.contentView addSubview:accessoryImageView];
or subclass of UITableViewCell and implement all views inside it
I am using table view using custom coding with tag method to save memory.
I was successful to show data in the view but the problem is if 10 cells are showing and then if I scroll down like for one cell then it should show 2-11 cell data but it switches to 1-10 again.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"cellID";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
UILabel *cellNAMElabl = nil;
UILabel *cellDetaillabl = nil;
UIImageView *imgView = nil;
if (cell == nil) {
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
cellNAMElabl = [[UILabel alloc] initWithFrame:CGRectMake(88, 10, 150, 20)];
[cellNAMElabl setTag:1];
cellNAMElabl.text = [name5 objectAtIndex:indexPath.row];
UIFont *myFont1 = [ UIFont fontWithName: #"Arial" size: 20.0 ];
cellNAMElabl.font = myFont1;
[cell.contentView addSubview:cellNAMElabl];
cellDetaillabl = [[UILabel alloc] initWithFrame:CGRectMake(88, 28, 150, 20)];
[cellDetaillabl setTag:2];
cellDetaillabl.text = [email5 objectAtIndex:indexPath.row];
UIFont *myFont = [ UIFont fontWithName: #"Arial" size: 13.0 ];
cellDetaillabl.font = myFont;
[cell.contentView addSubview:cellDetaillabl];
imgView=[[UIImageView alloc] initWithFrame:CGRectMake(25, 5, 52, 50)];
[imgView setTag:3];
imgView.image = [imagepath5 objectAtIndex:indexPath.row];
[cell.contentView addSubview:imgView];
}
cellNAMElabl = (UILabel *)[cell viewWithTag:1];
cellDetaillabl = (UILabel*)[cell viewWithTag:2];
imgView = (UIImageView*)[cell viewWithTag:3];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
You are not assigning new content to subviews, if they have been already created. After the case if(cell == nil), these you have just got references.
cellNAMElabl = (UILabel *)[cell viewWithTag:1];
cellDetaillabl = (UILabel*)[cell viewWithTag:2];
imgView = (UIImageView*)[cell viewWithTag:3];
Here when cell is not nil, you are just getting references to labels and imageview, but you are not setting new text and image from data source. Add following lines and remove them from the if (cell == nil) part:
cellNAMElabl.text = [name5 objectAtIndex:indexPath.row];
cellDetaillabl.text = [email5 objectAtIndex:indexPath.row];
imgView.image = [imagepath5 objectAtIndex:indexPath.row];
[cell.contentView addSubview:imgView];
The way this dequeueReusableCellWithIdentifier works: If iOS detects that a cell is not displayed anymore, then dequeueReusableCellWithIdentifier will return that cell. If there is no unused cell, it returns nil. So what you need to do:
If dequeueReusableCellWithIdentifier returns nil, then you create a new cell, and you do all the setup that is required for all cells with the same identifier. For example, add view tags like you did, set fonts, colors etc.
Then, whether you use a cell returned by dequeueReusableCellWithIdentifier or one that you just created yourself, you add all the information that is used for the specific section/row that you want to display. So if row 1, row2, and so on display different text, then you set the text here. That's what you didn't do, so when a cell was reused, you didn't set the new text for it.
So the idea is that all the work that is the same for all rows is only done once when a cell is created, and only as many cells are created as is needed to display them on the screen. The work that is different from row to row is done for each row, as it is needed.
If you set a breakpoint in the if cell == nil block its probably only being hit for the first set if your reuseID is correct. Thats why its never getting a chance to set any new data into the cell.
You should not look for a nil cell, rather use a correct reuseID and a prototype cell in IB that is set to a custom UITableViewCell subclass you create.
Its also good practice to implement prepareForReuse on custom cells, where you clear any cell data e.g. label.text = nil, imageview.image = nil
This way you dont get invalid data from previously dequeued cells. It might not solve the question directly, but it would have wiped the fixed data set in your if cell == nil block to help debug.
What you want to do is..
add/setup the tableViewCell UI if the cell is nil..
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"cellID";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:cellIdentifier];
UILabel *cellNAMElabl = [[UILabel alloc] initWithFrame:CGRectMake(88, 10, 150, 20)];
cellNAMElabl.tag = 1;
cellNAMElabl.font = [UIFont fontWithName: #"Arial" size: 20.0 ];
[cell.contentView addSubview:cellNAMElabl];
UILabel *cellDetaillabl = [[UILabel alloc] initWithFrame:CGRectMake(88, 28, 150, 20)];
cellDetaillabl.tag = 2;
cellDetaillabl.font = [UIFont fontWithName: #"Arial" size: 13.0 ];
[cell.contentView addSubview:cellDetaillabl];
UIImageView *imgView=[[UIImageView alloc] initWithFrame:CGRectMake(25, 5, 52, 50)];
imgView.tag = 3;
[cell.contentView addSubview:imgView];
}
//and just update your data if the cell is currently exist and not nil..
//you already called the view using tag so, you dont need those:
// UILabel *cellNAMElabl = nil;
// UILabel *cellDetaillabl = nil;
// UIImageView *imgView = nil;
((UILabel *)[cell viewWithTag:1]).text = [name5 objectAtIndex:indexPath.row]; // cellNAMElabl
((UILabel*)[cell viewWithTag:2]).text = [email5 objectAtIndex:indexPath.row]; // cellDetaillabl
((UIImageView*)[cell viewWithTag:3]).image = [imagepath5 objectAtIndex:indexPath.row]; // imgView
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
hope this have help you, happy coding cheers!
I have a strange problem using the dequeueReusableCellWithIdentifier: method of UITableView. Not sure if I don't understand the method well enough or is it just plain weird. Here goes:
Im using a UITableView which presents some data to users, and inside my
- (UITableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath I use the dequeue method like so:
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:#"cell"];
if (!cell)
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"cell"];
Afterwards I add some subviews to the contentView property of the cell. When scrolling a bit further down on my table I see those previously added subviews i.e. the cell is not empty but filled with "old" data. If I don't dequeue, and just alloc-init a new one each time, the cells are empty but I do see a bit more memory consumption which is precisely what Im trying to bring down a little. I'm using ARC if that means anything here.
What or how should I tackle the problem? I have tried running a for loop through the subviews of the content view and [view removeFromSuperview] which does remove the previous views and brings down memory consumption a little. But is that really necessary? Or is there a better way?
EDIT here is some more code how I add subviews
cell.backgroundView = [[UIView alloc] initWithFrame:cell.frame];
cell.backgroundColor = kClearColor; //defined to [UIColor clearColor]
cell.selectionStyle = UITableViewCellSelectionStyleNone;
if (indexPath.row == 0)
{
UIImageView *shine = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 50)];
shine.image = [UIImage imageNamed:#"top_shine_1"];
[cell.backgroundView addSubview:shine]; //its a gradient thats why its added to background
UILabel *appLabel = [[UILabel alloc] initWithFrame:CGRectMake(55, winSize.height * 0.027, 250, 33)];
appLabel.backgroundColor = kClearColor; //defined to clear color
appLabel.textColor = kWhiteColor; //defined to white color
appLabel.text = [viewOrder objectAtIndex:tableView.tag]; //just an array from where I get the required text
appLabel.font = kStandardFontOfSize(30); //defined to a specific font
[cell.contentView addSubview:appLabel];
UIButton *settingsButton = [UIButton buttonWithType:UIButtonTypeCustom];
settingsButton.frame = CGRectMake(10, winSize.height * 0.0377, 31, 21);
[settingsButton setImage:[UIImage imageNamed:#"settings_button"] forState:UIControlStateNormal];
[settingsButton addTarget:self action:#selector(settings:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:settingsButton];
return cell; //here I just return it since this is all the config the first cell needs
}
NSString *app = [viewOrder objectAtIndex:tableView.tag];
NSArray *boxes = [[plist secondObjectForKey:#"order" parent:app] componentsSeparatedByString:#";"];
//Add necessary shines or create the last logotype cell - just some details and stuff, all are just images
if (indexPath.row == 1)
{
UIImageView *shine = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, 320, 282.5)];
shine.image = [UIImage imageNamed:#"top_shine_2"];
[cell.backgroundView addSubview:shine];
}
else if (indexPath.row == 2)
{
UIImageView *shine = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, winSize.width, 150)];
shine.image = [UIImage imageNamed:#"main_shine"];
[cell.backgroundView addSubview:shine];
}
else if (indexPath.row == boxes.count + 1)
{
UIImageView *logo = [[UIImageView alloc] initWithFrame:CGRectMake(111.5, 25, 97, 20)];
logo.image = [UIImage imageNamed:#"cell_logo"];
[cell.backgroundView addSubview:logo];
return cell;
}
NSString *databox = [boxes objectAtIndex:indexPath.row - 1];
UIView *view; //Main subview to be added to the cell
/*
here I have a class that creates a view with a bunch of subviews added to that view, the view is then assigned to 'view'; kinda like
view = [someAssembler assembleViewWith:options.....]. all are basically UILabels or ImageViews added to the main view
*/
[cell.contentView addSubview:view]; //and here this 'main view' is added as a subview, this view is still visible after the cell has been dequeued and the shines are as well
return cell;
Before you start criticising why im not using a single UIColor for background and text color let me remind you that this is still in testing stage, it will be taken care of later.
[cell.backgroundView addSubview:shine]; these lines of code are the problem in your case.
You should create a complete reusable cell within the if (!cell) block and repopulate them each time cellForRow is being called. For every unique cell a unique reuse identifier should be used. For example, if you have multiple cells with differently laid out subviews, you should use different identifiers for them.
In your specific example cells must be created in the if (indexPath.row == 1) blocks.
static NSString *cellIdentifier = #"cell";
UITableViewCell *cell = nil;
if (indexPath.row == 0) {
cellIdentifier = #"topCell";
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
if (!cell) {
// create the cell and add the necessary subviews for indexPath row 0
}
return cell;
}
else if (indexPath.row == 1) {
}
//etc.
}
You'll have to create the "main subview" for each cell in the !cell block with this approach though, so you should probably look into subclassing a cell.
I'm trying to create a tableview where the height of the cells are dynamic.
So far I manage to set the height of the cells depending on the custom UILabel I've added inside.
With the regular cell.textLabel it works fine, but when I use my own label something goes wrong. I only see half the label, but when I scroll up and down, sometimes the label extends and shows all the text... You can see where the label should end in the image.
Image
This is the text inside the cellForRowAtIndexPath:
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
// Configure the cell.
Car *carForCell = [cars objectAtIndex:indexPath.row];
UILabel *nameLabel = [[UILabel alloc] init];
nameLabel = (UILabel *)[cell viewWithTag:100];
nameLabel.numberOfLines = 0;
nameLabel.text = carForCell.directions;
[nameLabel sizeToFit];
[nameLabel setBackgroundColor:[UIColor greenColor]];
return cell;
Unless you have typos in the code you posted, you don't seem to be adding the label to the cell at all. You also seem to be creating a new label every time, and then replacing the contents of your nameLabel pointer with the cell's view (which will always be nil).
Try doing something like this first and then see how it looks:
static NSString *CellIdentifier = #"Cell";
UILabel *nameLabel;
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
nameLabel = [[UILabel alloc] init];
nameLabel.tag = 100;
nameLabel.numberOfLines = 0;
[nameLabel setBackgroundColor:[UIColor greenColor]];
[cell.contentView addSubview:nameLabel];
}
else {
nameLabel = (UILabel *)[cell viewWithTag:100];
}
// Configure the cell.
Car *carForCell = [cars objectAtIndex:indexPath.row];
nameLabel.text = carForCell.directions;
[nameLabel sizeToFit];
return cell;
You will also need to tell the tableView what size each cell needs to be using the tableView:heightForRowAtIndexPath: delegate method. That will mean getting the relevant Car object again and calculating the height using sizeWithFont:sizeWithFont:forWidth:lineBreakMode:
How are you setting the height of the cell? It should be done in - (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
You should calculate and return the height of the UITableViewCell in the following method:
- (CGFloat) tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath;
Here you should do your initial calculation of how high your cell should be.
For example:
CGSize textSize = [myString sizeWithFont:[UIFont systemFontOfSize:16] constrainedToSize:CGSizeMake(320, 9999)];
return textSize.height;
I'm having problems implementing a table row that allows text to wrap to multiple lines, and also has an image on the left, and a disclosure accesssory on the right.
The multiline text is fine but the imageView expands to the right when there is more than one line of text. I want images in all rows to be the same size. I've tried setting the autoresizingMask to UIViewAutoresizingNone but this doesn't seem to work.. Do I need to use the contentView, or a nib file?
Any help/example code appreciated!
If all off your images are different size then you should think of adding a ImageView as Subview to cell. Keep Labels depending on the Imageview.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell;
UIImageView *cellImage;
UILabel *label;
UILabel *detailLabel;
cell = [tableView dequeueReusableCellWithIdentifier:#"cell"]; //Create cell
if(cell == nil)
{
cell = [[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:#"cell"] autorelease];
cellImage = [[[UIImageView alloc] initWithFrame:CGRectMake(3, 3, 44, 44)] autorelease];
label = [[[UILabel alloc] initWithFrame:CGRectMake(55, 4, 260, 20)] autorelease];
label.font = [UIFont boldSystemFontOfSize:15.0];
label.tag=25;
detailLabel = [[[UILabel alloc] initWithFrame:CGRectMake(55, 25, 260, 15)] autorelease];
detailLabel.font = [UIFont systemFontOfSize:13.0];
detailLabel.tag=30;
[cell.contentView addSubview:cellImage];
[cell.contentView addSubview:label];
[cell.contentView addSubview:detailLabel];
cell.accessoryType =UITableViewCellAccessoryDisclosureIndicator;
}
else
{
cellImage = (UIImageView *)[cell.contentView viewWithTag:20];
label = (UILabel *)[cell.contentView viewWithTag:25];
detailLabel = (UILabel *)[cell.contentView viewWithTag:30];
}
cell.image = [arrayContainingImages objectAtIndex:indexPath.row];
label.text =[arrayContaininglabeltext objectAtIndex:indexPath.row];
detailLabel.text=[arrayContainingDetailLabelText objectAtIndex:indexPath.row];
return cell;
}
pls see Stop image expanding in multiline table row? #2