How to change one UITableViewCell when it is touched - objective-c

I have a table view cell with multiple images in them. When touching the images they shold display an overlay on top of the image which tells the user that this image was selected.
Is there a way to change the look of just one UITableViewCell without having to do a [tableView reloadData] which would allow me to style the cell differently in the table view datasource delegate method.

The way I would do it is to subclass UITableViewCell and then on tableView:didSelectRowAtIndexPath: get a reference to the cell and do whatever you want to it (or just target the image touch event if this is not a selection).
There might be another way of doing this without having to subclass, but I find myself subclassing UITableViewCell all the time and it's pretty straightforward to do.

If you wish to avoid subclassing, this can be achieved with gesture recognisers. Your question suggests a Tap and Hold user interaction on each image, which I have implemented in the code below. One point to remember, if the user is tapping and holding, they may not see the text you wish them to see.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = #"ImageCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (!cell) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier] autorelease];
}
UILongPressGestureRecognizer *recognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(imageTapped:)];
UILongPressGestureRecognizer *recognizer2 = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(imageTapped:)];
UIImageView *imageView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"Ben.png"]];
imageView.frame = CGRectMake(cell.contentView.bounds.origin.x,cell.contentView.bounds.origin.y , 100, 40);
imageView.userInteractionEnabled = YES;
[imageView addGestureRecognizer:recognizer];
[cell.contentView addSubview:imageView];
UIImageView *imageView2 = [[UIImageView alloc] initWithImage:[UIImage imageNamed:#"Steve.png"]];
imageView2.frame = CGRectMake(cell.contentView.bounds.origin.x + imageView.frame.size.width + 10,cell.contentView.bounds.origin.y , 100, 40);
imageView2.userInteractionEnabled = YES;
[imageView2 addGestureRecognizer:recognizer2];
[cell.contentView addSubview:imageView2];
[imageView release];
[imageView2 release];
[recognizer release];
[recognizer2 release];
return cell;}
- (void)imageTapped:(id)sender {
NSLog(#"%#", sender);
UILongPressGestureRecognizer *recognizer = (UILongPressGestureRecognizer *)sender;
if (recognizer.state == UIGestureRecognizerStateBegan) {
UILabel *label = [[UILabel alloc] initWithFrame:recognizer.view.bounds];
label.text = #"Pressed";
label.backgroundColor = [UIColor clearColor];
label.tag = 99999;
label.textColor = [UIColor whiteColor];
[recognizer.view addSubview:label];
[label release];
}
else {
[[recognizer.view viewWithTag:99999] removeFromSuperview];
}
}
Hope this helps.

Related

How do I clear a cell completely when I reuse it?

When I call [table reloaddata];
The cells get redrawn with new data, but my UILabels get messed up because they are drawn over the old UILabels, so its a mess.
static NSString* PlaceholderCellIdentifier = #"PlaceholderCell";
UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:PlaceholderCellIdentifier];
if (cell == nil)
{
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:PlaceholderCellIdentifier] autorelease];
cell.detailTextLabel.textAlignment = UITextAlignmentCenter;
cell.selectionStyle = UITableViewCellSelectionStyleNone;
cell.contentView.backgroundColor = [UIColor clearColor];
}
Is my Init of the cell.
I add a UILabel like so
UILabel *theDateLabel = [[UILabel alloc] initWithFrame:CGRectMake(140, 35,140, 20)];
[theDateLabel setBackgroundColor:[UIColor clearColor]];
[theDateLabel setTextColor:[UIColor lightGrayColor]];
[theDateLabel setText:[dateFormatter stringFromDate:theDate]];
[theDateLabel setFont:[UIFont fontWithName:#"TrebuchetMS-Bold" size:15]];
[cell addSubview:theDateLabel];
[theDateLabel release];
There are a few more labels in the cell, same thing.
What I would like to happen is that the old labels disappear from the cell so that they are no longer visible.
You should not add theDateLabel as a subview of cell. You should add it as a subview of cell.contentView.
As yuji suggests, one way to implement this is to create a subclass of UITableViewCell with a property for each custom subview. That way you can easily get to the date label of a reused cell to set its text for the new row.
Another common approach is to use the tag property that every UIView has. For example:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString* PlaceholderCellIdentifier = #"PlaceholderCell";
static const int DateLabelTag = 1;
UITableViewCell* cell = [tableView dequeueReusableCellWithIdentifier:PlaceholderCellIdentifier];
if (!cell) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:PlaceholderCellIdentifier] autorelease];
UILabel *theDateLabel = [[UILabel alloc] initWithFrame:CGRectMake(140, 35,140, 20)];
theDateLabel.tag = DateLabelTag;
theDateLabel.backgroundColor = [UIColor clearColor];
theDateLabel.textColor = [UIColor lightGrayColor];
theDateLabel.font = [UIFont fontWithName:#"TrebuchetMS-Bold" size:15];
[cell.contentView addSubview:theDateLabel];
[theDateLabel release];
}
NSDate *theDate = [self dateForRowAtIndexPath:indexPath];
UILabel *theDateLabel = [cell.contentView viewWithTag:DateLabelTag];
theDateLabel.text = [dateFormatter stringFromDate:theDate];
return cell;
}
While Richard's solution will work, if your cells have any other subviews they'll get removed as well. Also, allocating and initializing your subviews every time you draw a cell isn't necessarily optimal.
The standard solution here is to create a subclass of UITableViewCell with a property #dateLabel (and so on for the other labels). Then, when you're initializing a cell, if it doesn't have a #dateLabel yet you can give it a new one, otherwise you only have to set its text.

Adding extra UIlabel to each cell

I'm trying to add an extra UILabel into each cell(UITableView)
I'v succeeded with this code in
(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath method
Here's my code
//add another text
UILabel *test = [[UILabel alloc] initWithFrame:CGRectMake(250,80,50,20.0)];
test.text = [NSString stringWithFormat: #"test"];
test.backgroundColor = [UIColor clearColor];
test.font=[UIFont fontWithName:#"AppleGothic" size:20];
[cell addSubview:test];
However I figured that if I do this, I can't add different text to each cell, instead, it ends up with the same text in all cells. Can anyone tell me how to do that?
Oh and another problem was that if I do this, "test" is displayed in every cell except for the first one.
Have a look at the tutorial "UITableView – Adding subviews to a cell’s content view".
Try something like this
- (UITableViewCell *) getCellContentView:(NSString *)cellIdentifier {
CGRect CellFrame = CGRectMake(0, 0, 320, 65);
CGRect Label1Frame = CGRectMake(17,5,250,18);
UILabel *lblTemp;
UITableViewCell *cell = [[[UITableViewCell alloc] initWithFrame:CellFrame reuseIdentifier:cellIdentifier] autorelease];
lblTemp = [[UILabel alloc] initWithFrame:Label1Frame];
[lblTemp setFont:[UIFont fontWithName:#"Arial-BoldMT" size:15]];
lblTemp.tag = 1;
lblTemp.backgroundColor=[UIColor clearColor];
lblTemp.numberOfLines=0;
[cell.contentView addSubview:lblTemp];
return cell; // this I forgot
}
in cellForRowAtIndexPath
{
if(cell == nil)
cell = [self getCellContentView:CellIdentifier];
UILabel *lblTemp1 = (UILabel *)[cell viewWithTag:1];
lblTemp1.text =[nameArray objectAtIndex:value+indexPath.row];
return cell;
}
For having the same Label on all cells, you are probably instantiating just one cell and use the cellReUseIdentifier for all cells. So, I suggest that you create different labels as properties of the class, and assign each property-label to each cell.
// For example -
if (indexPath.row ==0 )
// assign [cell.contentView addSubview: self.label1];
if (indexPath.row ==1 )
// assign [cell.contentView addSubview: self.label2];
And for the second part of the question, please post your cellForRowAtIndexPath fully - there could be an error in that.
First check if any of the predefined styles work for you.
If you need more flexibility than what they offer, you can try something like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [self makeCell: CellIdentifier];
}
MyData *data = [self.data objectAtIndex:indexPath.row];
UILabel *lbl1 = (UILabel *)[cell viewWithTag:1];
UILabel *lbl2 = (UILabel *)[cell viewWithTag:2];
lbl1.text = data.text;
lbl2.text = data.auxText;
return cell;
}
- (UITableViewCell *)makeLensListCell: (NSString *)identifier
{
CGRect lbl1Frame = CGRectMake(10, 0, 140, 25);
CGRect lbl2Frame = CGRectMake(10, 150, 140, 25);
UILabel *lbl;
UITableViewCell *cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:identifier] autorelease];
// Label with tag 1.
lbl = [[UILabel alloc] initWithFrame:lbl1Frame];
lbl.tag = 1;
[cell.contentView addSubview:lbl];
[lbl release];
// Label with tag 2.
lbl = [[UILabel alloc] initWithFrame:lbl2Frame];
lbl.tag = 2;
lbl.textColor = [UIColor lightGrayColor];
[cell.contentView addSubview:lbl];
[lbl release];
// Add as many labels and other views as you like
return cell;
}
This approach also allows images and other views.

My UITableView do not scroll

I cannot get my UITableView to load data as i am scrolling. I do have subview in the cell (two lines). It display the first screen correctly but when i scroll only the lines that is on the first screen displays, nothing to scroll.
I have two arrays cellArray1 (main line) and cellArray2 (second line) that I load data from.
I would very much appreciate help to solve this, possible, simple problem.
Here is what i think is relevant code for this question:
- (UITableViewCell *) getCellContentView:(NSString *)cellIdentifier
{
CGRect CellFrame = CGRectMake(0, 0, 300, 60);
CGRect Label1Frame = CGRectMake(10, 10, 290, 25);
CGRect Label2Frame = CGRectMake(30, 33, 270, 25);
UILabel *lblTemp;
UITableViewCell *cell = [[[UITableViewCell alloc] initWithFrame:CellFrame reuseIdentifier:cellIdentifier] autorelease];
//Initialize Label with tag 1.
lblTemp = [[UILabel alloc] initWithFrame:Label1Frame];
lblTemp.backgroundColor = [UIColor orangeColor];
[lblTemp setFont:[UIFont fontWithName:#"American Typewriter" size:16]];
lblTemp.tag = 1;
[cell.contentView addSubview:lblTemp];
[lblTemp release];
//Initialize Label with tag 2.
lblTemp = [[UILabel alloc] initWithFrame:Label2Frame];
lblTemp.backgroundColor = [UIColor orangeColor];
lblTemp.tag = 2;
[lblTemp setFont:[UIFont fontWithName:#"American Typewriter" size:13]];
lblTemp.textColor = [UIColor whiteColor];
[cell.contentView addSubview:lblTemp];
[lblTemp release];
return cell;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) cell = [self getCellContentView:CellIdentifier];
UILabel *lblTemp1 = (UILabel *)[cell viewWithTag:1];
UILabel *lblTemp2 = (UILabel *)[cell viewWithTag:2];
lblTemp1.text = [cellArray1 objectAtIndex:indexPath.row];
lblTemp2.text = [cellArray2 objectAtIndex:indexPath.row];
tableView.backgroundColor = [UIColor orangeColor];
return cell;
}
The answer to this problem was that I had hard coded a parameter that dictate how many items that was loaded during my testing.
I just found the problem, i had hard coded a parameter that dictated how many items that was

			
				
Make sure you are adding to the correct view if you are creating programatically and adding as subview to main view.

UITableViewCell - overlapping with previous cells contents

I have this wierd problem with my table
i Have about 20 cells to display
Each cell is about 84px in height
When i click no the cell, i have set a background colour
The first 4 cells are ok, but when i scroll down and click on the 5th cell, the content of each cell starts to overlap with some other content, usually content from 1st 4 cells.
I belive its some cell reusability or drawing issue. Am not sure how to solve it, i have checked through my code, but i am not changing the cell's content on touch.
Here is my code and will add some pics too
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
return 104;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return [stores count];
}
-(UITableViewCell *)tableView:(UITableView *) tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
CGRect Label1Frame = CGRectMake(5, 5, 250, 30);
CGRect Label2Frame = CGRectMake(6, 42, 220, 20);
CGRect Label3Frame = CGRectMake(6, 62, 220, 20);
CGRect Label4Frame = CGRectMake(240,56, 70, 12);
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleValue1 reuseIdentifier:CellIdentifier] autorelease];
}else{
// a cell is being recycled, remove the old edit field (if it contains one of our tagged edit fields)
UIView *viewToCheck = nil;
viewToCheck = [cell.contentView viewWithTag:1];
if (!viewToCheck) {
[viewToCheck removeFromSuperview];
DebugLog(#"View removed");
}
}
//cell.selectionStyle=UITableViewCellSelectionStyleNone;
[cell setSelectedBackgroundView:bgView];
NSInteger row=indexPath.row;
UILabel *lblTemp;
[[cell contentView] clearsContextBeforeDrawing];
//Line 1
lblTemp=[[UILabel alloc] initWithFrame: Label1Frame];
lblTemp.tag=1;
lblTemp.text=[[stores objectAtIndex:row] objectAtIndex:0] ;
lblTemp.numberOfLines=2;
lblTemp.font = [UIFont boldSystemFontOfSize:13];
lblTemp.adjustsFontSizeToFitWidth=YES;
lblTemp.minimumFontSize=12;
lblTemp.textColor = [UIColor grayColor];
[cell.contentView addSubview:lblTemp];
[lblTemp release];
//Line 2
lblTemp = [[UILabel alloc] initWithFrame:Label2Frame];
lblTemp.tag = 2;
lblTemp.text=[[stores objectAtIndex:row]objectAtIndex:1];
lblTemp.font = [UIFont systemFontOfSize:12];
lblTemp.textColor = [UIColor grayColor ];
lblTemp.textAlignment=UITextAlignmentLeft;
lblTemp.adjustsFontSizeToFitWidth=YES;
lblTemp.minimumFontSize=12;
[cell.contentView addSubview:lblTemp];
[lblTemp release];
//Line 3
lblTemp = [[UILabel alloc] initWithFrame:Label3Frame];
lblTemp.tag = 3;
lblTemp.text=[[stores objectAtIndex:row]objectAtIndex:2];
lblTemp.font = [UIFont systemFontOfSize:12];
lblTemp.textColor = [UIColor grayColor ];
[cell.contentView addSubview:lblTemp];
[lblTemp release];
//Phone button
UIButton *phoneButton=[[UIButton alloc] initWithFrame:CGRectMake(240,16,30,30)];
[phoneButton setBackgroundImage:[UIImage imageNamed:#"phone.png"] forState:UIControlStateNormal];
[phoneButton setTag:row];
[phoneButton addTarget:self action:#selector(dialNumber:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:phoneButton];
//ANnotation button
UIButton *annotation=[[UIButton alloc] initWithFrame:CGRectMake(274,16,30,30)];
[annotation setTag:row];
[annotation setBackgroundImage:[UIImage imageNamed:#"tab.png"] forState:UIControlStateNormal];
[annotation addTarget:self action:#selector(openMap:) forControlEvents:UIControlEventTouchUpInside];
[cell.contentView addSubview:annotation];
[annotation release];
//Distance label
//Line 3
lblTemp = [[UILabel alloc] initWithFrame:Label4Frame];
lblTemp.tag = 4;
lblTemp.text=[[stores objectAtIndex:row]objectAtIndex:5];
lblTemp.textAlignment=UITextAlignmentCenter;
lblTemp.font = [UIFont systemFontOfSize:13];
lblTemp.textColor = [UIColor grayColor ];
[lblTemp setAdjustsFontSizeToFitWidth:YES];
[cell.contentView addSubview:lblTemp];
[phoneButton release];
[lblTemp release];
[cell setNeedsLayout];
[cell setNeedsDisplay];
return cell;
}
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell=[tableView cellForRowAtIndexPath:indexPath ];
for(UILabel *lbl in cell.contentView.subviews){
if([lbl isKindOfClass:[UILabel class]]){
lbl.textColor=[UIColor whiteColor];
}
}
//UITableViewCell *cell1;
//NSString *row=[NSString stringWithFormat:#"%d",indexPath.row];
svm = [[storesMapView alloc] initWithNibName:#"storesMapView" bundle:nil];
[svm initWithXML:stores:indexPath.row];
CGRect theFrame = svm.view.frame;
theFrame.origin = CGPointMake(self.view.frame.size.width, 0);
svm.view.frame = theFrame;
theFrame.origin = CGPointMake(0,0);
theFrame.size=CGSizeMake(320,355);
[UIView beginAnimations:nil context:nil];
[UIView setAnimationDuration:0.3f];
svm.view.frame = theFrame;
[UIView commitAnimations];
[subView addSubview:svm.view];
backButton.hidden=NO;
}
I figured it out with some trial and error; if this can help some one
In cellforRowAtIndexPath i tried to clear all the cells subview before drawing the cell
//TRY TO REMOVE ALL CONTENT
for(UIView *view in cell.contentView.subviews){
if ([view isKindOfClass:[UIView class]]) {
[view removeFromSuperview];
}
}
I would be happy if someone can point me to some easier way
Thanks
You can use
[[[cell contentView] subviews] makeObjectsPerformSelector: #selector(removeFromSuperview)];
If the cell in not nil, the above code will reduce the time for using the for loop similar to this
for(UIView *eachView in [cell subviews])
[eachView removeFromSuperview];
I also had the same issue.I also had composed tableView with labels.And when I scroll it down the contents got overlapped.But it got solved simply by editing one statement in cellForRowAtIndexPath.
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:nil];
I think this will solve your problem.
I know this is a bit late, but I had a similar issue where UILabels created for a cell were still part of the cell when it was reused. So each successive update of the tableview created another UILabel on top of the existing one. I moved the creation of the Labels into the if condition as below and it resolved my issue. Hope it helps someone else. Also note no release as I am using ARC.
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cityText = [[UILabel alloc] initWithFrame:CGRectMake(10, 10, 100, 20)];
cityText.font = [UIFont fontWithName:#"Arial" size:20];
cityText.textAlignment = UITextAlignmentLeft;
cityText.backgroundColor = [UIColor clearColor];
regionText = [[UILabel alloc] initWithFrame:CGRectMake(10, 40, 100, 20)];
regionText.font = [UIFont fontWithName:#"Arial" size:20];
regionText.textAlignment = UITextAlignmentLeft;
regionText.backgroundColor = [UIColor clearColor];
}
Setting nil to label text on UITableViewCell subclass 's method prepareForReuse() solved my problem -
override func prepareForReuse() {
super.prepareForReuse()
self.label1.text = nil
self.label2.text = nil
....
}
Shared if it helps anyone!

Why the dummy text can't load on my cell?

This is the tableView, as you can see, which cell, have two part, the left one, is a leftUIView, and right one, is the rightUIView. The red and green color can display, but the rightLabel I create can't show successfully. What's wrong with my code? Thank you.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *SectionsTableIdentifier = #"SectionsTableIdentifier";
UITableViewCell *cell = [self.tableView dequeueReusableCellWithIdentifier:SectionsTableIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:SectionsTableIdentifier] autorelease];
}
cell.textLabel.textColor = [UIColor whiteColor];
UIView *rightUIView = [[UIView alloc] initWithFrame:CGRectMake(160, 0, 160, cell.frame.size.height)];
[rightUIView setBackgroundColor:[UIColor greenColor]];
UIView *leftUIView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 160, cell.frame.size.height)];
[leftUIView setBackgroundColor:[UIColor redColor]];
UILabel *rightLabel = [[UILabel alloc] init];
[rightLabel setText:#"dummy"];
[rightUIView addSubview:rightLabel];
[cell addSubView:leftUIView];
[cell addSubView:rightUIView];
}
The first problem with your code is that you create cell's subviews each time cell is requested - if you scroll your table to and fro your cell will have a bunch of those subviews - certainly that's not good. You must create cell subviews only once - when you create the cell and after that only set appropriate values to them:
const int kRightViewTag = 100;
const int kRightLabelTag = 200;
...
if (cell == nil) {
// Create everything here
cell = [[[UITableViewCell alloc]
initWithStyle:UITableViewCellStyleSubtitle
reuseIdentifier:SectionsTableIdentifier] autorelease];
cell.textLabel.textColor = [UIColor whiteColor];
UIView *rightUIView = [[UIView alloc] initWithFrame:CGRectMake(160, 0, 160, cell.frame.size.height)];
rightUIView.tag = kRightViewTag;
[rightUIView setBackgroundColor:[UIColor greenColor]];
[rightUIView release]; // Do not forget to release object you allocate!!
UIView *leftUIView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 160, cell.frame.size.height)];
[leftUIView setBackgroundColor:[UIColor redColor]];
[leftUIView release]; // Do not forget to release object you allocate!!
UILabel *rightLabel = [[UILabel alloc] initWithFrame:leftUIView.bounds];
rightLabel.tag = kRightLabelTag;
[rightUIView addSubview:rightLabel];
[rightLabel release];
}
// Setup values here
UILabel* rightLabel = (UILabel*)[[cell viewWithTag:kRightViewTag] viewWithTag:kRightLabelTag];
rightLabel.text = #"dummy";
The second thing is you do not set label's frame anywhere (I've fixed that above) so it is likely has zero-sized frame and that's why you cannot see it.
The 3rd problem is that you allocate views but don't release them - so they just leak. Do not forget that if you create some objects using alloc, new or copy then you're responsible for releasing them.