UITableView crashing on scroll - iphone

This is the code i have:
- (id)init
{
self = [super initWithStyle:UITableViewStylePlain];
if (self) {
//self.tableView.delegate = self;
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
UIColor *wood = [UIColor colorWithPatternImage:[UIImage imageNamed:#"wood_pattern.png"]];
self.view.backgroundColor = wood;
self.tableView.separatorColor = [UIColor clearColor];
}
#pragma mark - Table view data source
- (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 = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cell.backgroundView.backgroundColor = [UIColor redColor];
}
// Configure the cell...
cell.textLabel.text = #"Test";
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
}
-(CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 60;
}
When i scroll down and then back up to a cell which was previously on screen, the app crashes. Any ideas why?
On a side note.. the background color is set to red, and although i can see the text, I can't see the background color.

Bind UITableView properly in XIB. and right following code.
- (void)viewDidLoad {
[super viewDidLoad];
self.tableView.separatorColor = [UIColor clearColor];
}
- (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 = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
cell.contentView.backgroundColor = [UIColor redColor];
cell.textLabel.text = #"Test";
cell.textLabel.backgroundColor = [UIColor clearColor];
cell.accessoryType = UITableViewCellAccessoryDisclosureIndicator;
// Configure the cell.
return cell;
}

Related

UITableViewCell keeps getting deselected

I have a strange problem with UITableView:
My tableview shows the names of objects from which the user can select one. The value is saved. When the tableview comes up the row is selected (in cellForRowAtIndexPath). But in viewWillAppear the row is first selected and then deselected. You can see that it is first selected because of a the blue background occurs for a short time.
I have set
self.clearsSelectionOnViewWillAppear = NO;
but that does not work ether. Can someone help me out please! Thanks in advance.
Here some sample code:
#import "ECTESTTableViewController.h"
#interface ECTESTTableViewController ()
#end
#implementation ECTESTTableViewController
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.clearsSelectionOnViewWillAppear = NO;
}
#pragma mark - Table view data source
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
// Return the number of sections.
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
// Return the number of rows in the section.
return 8;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (!cell)
{
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];
// cell.selectionStyle = UITableViewCellSelectionStyleNone;
//cell.backgroundColor = [UIColor redColor];
}
if (indexPath.row == 1)
{
// cell.accessoryType = UITableViewCellAccessoryCheckmark;
NSLog(#"select %d", indexPath.row);
cell.selected = TRUE;
}
else {
// cell.accessoryType = UITableViewCellAccessoryNone;
cell.selected = FALSE;
}
cell.textLabel.text = [NSString stringWithFormat:#"row %d", indexPath.row];
return cell;
}
#end
If you want to programatically select a row in a UITableView use:
- (void)selectRowAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated scrollPosition:(UITableViewScrollPosition)scrollPosition
Don't be setting the selected states of the cells.
Write following code
NSIndexPath *indexPath = [tableView indexPathForSelectedRow];
[tableView selectRowAtIndexPath:indexPath animated:NO scrollPosition: UITableViewScrollPositionNone];

How to maintain state of selection of row in table view?

i am a beginner in xcode. I am creating a questionnaire type list with multiple rows in scroll. But when I select a row and scroll it doesn't retains its state and when I come back, it also loses its selection. So anyone please kindly let me know how to achieve that,i have tried something like this,
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
if(val==1)
{
checkedArr=[[NSMutableArray alloc] init];
for (int i = 0; i<17; i++)
{
[checkedArr addObject:#"1"];
}
NSLog(#"Checked arr size %i",[checkedArr count]);
return 17;
}
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
NSString *CellIdentifier = [NSString stringWithFormat:#"Cell%i",indexPath.row];
cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if(cell==nil)
{
cell= [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cell.textLabel.numberOfLines = 0;
cell.textLabel.font = [UIFont fontWithName:#"Helvetica" size:14.0];
}
cell.textLabel.font = [UIFont fontWithName:#"Helvetica-Bold" size:18.0];
UIView *selectionColor = [[UIView alloc] init];
selectionColor.backgroundColor = [UIColor colorWithRed:99/255.0f green:209/255.0f blue:248/255.0f alpha:1.0];
cell.selectedBackgroundView = selectionColor;
if([[checkedArr objectAtIndex:indexPath.row] isEqual:#"0"])
{
cell.accessoryView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:#"tick.png"]];
NSLog(#"checkedArr 0000000");
}
else if ([[checkedArr objectAtIndex:indexPath.row] isEqual:#"1"])
{
cell.accessoryView=nil;
NSLog(#"checkedArr 111111");
}
cell.textLabel.frame=CGRectMake(75.0, 50.0, 150.0, 20.0);
cell.textLabel.text=[listArray objectAtIndex:indexPath.row];
NSLog(#"Checked arr size %i",[checkedArr count]);
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
cell=[questionTable cellForRowAtIndexPath:indexPath];
[checkedArr replaceObjectAtIndex:indexPath.row withObject:#"0"];
if([[checkedArr objectAtIndex:indexPath.row] isEqual:#"0"])
{
cell.accessoryView=[[UIImageView alloc] initWithImage:[UIImage imageNamed:#"tick.png"]];
NSLog(#"checkedArr 0000000");
}
else if ([[checkedArr objectAtIndex:indexPath.row] isEqual:#"1"])
{[questionTable deselectRowAtIndexPath:indexPath animated:YES];
cell.accessoryView=nil;
NSLog(#"checkedArr 111111");
}
NSLog(#"Val is %i",val);
NSLog(#"selected is %#",[listArray objectAtIndex:indexPath.row]);
// NSLog(#"Checked arr descripton %#",[checkedArr description]);
}
-(void)tableView:(UITableView *)tableView didDeselectRowAtIndexPath:(NSIndexPath *)indexPath
{
[tableView cellForRowAtIndexPath:indexPath].accessoryView = UITableViewCellAccessoryNone;
}
In my application i used same code for check mark as accessoryType,check this.
take it in .h file mutable array arSelectedRows;
- (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 setSelectionStyle:UITableViewCellSelectionStyleGray];
//Do anything you want for cell here
if([arSelectedRows containsObject:indexPath]) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
else {
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}
#pragma mark - Table view delegate
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if(cell.accessoryType == UITableViewCellAccessoryNone) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
[arSelectedRows addObject:indexPath];
}
else {
cell.accessoryType = UITableViewCellAccessoryNone;
[arSelectedRows removeObject:indexPath];
}
NSLog(#"arSelectedRows are :%#",arSelectedRows);
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}
EDIT
//if you want only single check mark
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
[arSelectedRows removeAllObjects];
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if(cell.accessoryType == UITableViewCellAccessoryNone) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
[arSelectedRows addObject:indexPath];
}
else {
cell.accessoryType = UITableViewCellAccessoryNone;
[arSelectedRows removeObject:indexPath];
}
NSLog(#"arSelectedRows are:%#",arSelectedRows);
[self.tableview reloadData];//Reload your tableview here
}
it will help you.
First your cellForRowAtIndexPath method create new cell each time whenever you scroll up/down tableView, it is very bad for memory management.
Just remove [questionTable deselectRowAtIndexPath:indexPath animated:YES] in your cellForRowAtIndexPath method
I think you need to use this api below:-
- (void)selectRowAtIndexPath:(NSIndexPath *)indexPath animated:(BOOL)animated scrollPosition:(UITableViewScrollPosition)scrollPosition
If you are using dynamic cells, and updating your row with some kind of class variable like a NSArray, you might have set your variable to weak instead of strong.

table view containg image view

i ve got an imageview ..below the imageview is a table view..which loads the data from server.by default five fields in table view are visible ..works fine..if i m to scroll the table view to view the remaining fields..the scroller rebounces..wat i want is the table view to be fixed and not to rebounce when scrolled ..i d be so greatful if u guys cud help me out..below is the code..
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [items count];
}
- (CGFloat)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section
{
return 28.0;
}
- (UIView *) tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section
{
UIView *headerView = [[[UIView alloc] initWithFrame:CGRectMake(0, 0,
tableViewteam.bounds.size.width, 28)] autorelease];
headerView.backgroundColor=[UIColor colorWithPatternImage:[UIImage imageWithContentsOfFile:[[NSBundle mainBundle]pathForResource:#"team"ofType:#"png"]]];
return headerView;
}
- (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];
}
cell.selectionStyle=UITableViewCellSelectionStyleNone;
cell.imageView.backgroundColor=[UIColor clearColor];
cell.textLabel.text=[[items objectAtIndex:indexPath.row]objectForKey:#"title"];
cell.textLabel.textColor=[UIColor whiteColor];
cell.accessoryType=UITableViewCellAccessoryDisclosureIndicator;
return cell;
}
I didn't fully understand your problem. If you want to stop bouncing the table view you can add
yourTableView.bounces = NO;
in ViewDidLoad()
If you need your tableView to be fixed you can disable scrolling.
tableView.scrollEnabled = NO;

How to manage cellForRowAtIndexPath for tableViewIndexSearch?

how to manage cellForRowAtindexPath Value for TableViewIndexSearch my code is :
- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
alphabetDict = [NSDictionary dictionaryWithObject:tempArray forKey:#"alphabet"];
NSLog(#"alphabetDict Is: %#", alphabetDict);
[listArray addObject:alphabetDict];
NSLog(#"listArray Is: %#", listArray);
return tempArray;
}
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 26;
}
- (UIView *)tableView:(UITableView *)tableView viewForHeaderInSection:(NSInteger)section {
UIView *headerView = [[[UIView alloc] initWithFrame:CGRectMake(0,0,tableView.frame.size.width,30)] autorelease];
UILabel *headerLabel = [[UILabel alloc] initWithFrame:CGRectMake(10, -5, headerView.frame.size.width-120.0, headerView.frame.size.height)];
for(section ; section <=[self.tempArray count];section++)
{
headerLabel.textAlignment = UITextAlignmentLeft;
headerLabel.text = [self.tempArray objectAtIndex:section];
headerLabel.textColor = [UIColor whiteColor];
headerLabel.backgroundColor = [UIColor clearColor];
headerLabel.font = [UIFont fontWithName:#"Verdana Bold" size:11];
[headerView setBackgroundColor:[UIColor orangeColor]];
// NSLog(#"headerLabel.text:%#", headerLabel.text);
[headerView addSubview:headerLabel];
[headerLabel release];
return headerView;
}
return headerView;
}
-(float)tableView:(UITableView *)tableView heightForHeaderInSection:(NSInteger)section {
return 23.0;
}
// --------- TableView Delegate and DataSource-----------
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [xmlParseArray count];
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
DirectoryCustomCell *directoryCustomCell =(DirectoryCustomCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (directoryCustomCell == nil) {
directoryCustomCell = [[[DirectoryCustomCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
directoryCustomCell.selectionStyle = UITableViewCellEditingStyleNone;
}
UIImageView *searchImg = [[UIImageView alloc]initWithFrame:CGRectMake(292, 0, 28, 360)];
searchImg.image = [UIImage imageNamed:#"searchindex.png"];
[directoryCustomCell addSubview:searchImg];
NSString *companyName = [[xmlParseArray objectAtIndex:indexPath.row ]objectForKey:#"firstname"];
// NSLog(#"companyName :%#",companyName);
NSString *flName = [[xmlParseArray objectAtIndex:indexPath.row ]objectForKey:#"title"];
[directoryCustomCell setDataForEvent1:companyName venue:flName];
return directoryCustomCell;
}
- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {
return [[collation sectionTitles] objectAtIndex:section];
}
- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {
return [collation sectionForSectionIndexTitleAtIndex:index];
}
I want to show in sorted form (I mean section headertitle A have the name start from A and so on).
Between Headertitle from A to B these data are common in every section but I want only those starts from A in SectionHeadertitle A and starts from B in headertitle B.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
switch(indexPath.section)
{
// Configure based on section
// Get details corresponding to section
}
// configure cell and return cell
}
Take a look at this tutorial

Why don't tablecells get released?

I simplified my code to test with, and still on the phone my memory usage keeps climbing to a point where the table slows way down.
Can someone tell me what I'm doing wrong here?
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 40;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 100;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellID = #"Cell";
[self.tableView deselectRowAtIndexPath:indexPath animated:YES];
UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellID];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:cellID] autorelease];
}
UILabel *l=[[UILabel alloc] initWithFrame:CGRectMake(10,10,300,16)];
l.font=[UIFont boldSystemFontOfSize:15];
l.textColor=[UIColor whiteColor];
l.backgroundColor=[UIColor blackColor];
l.text=#"Just some randoom text here";
[cell.contentView addSubview:l];
[l release];
Oops. That code paste didn't work too well. Here's a straight paste:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 40;
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
return 100;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellID = #"Cell";
[self.tableView deselectRowAtIndexPath:indexPath animated:YES];
UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellID];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:cellID] autorelease];
}
UILabel *l=[[UILabel alloc] initWithFrame:CGRectMake(10,10,300,16)];
l.font=[UIFont boldSystemFontOfSize:15];
l.textColor=[UIColor whiteColor];
l.backgroundColor=[UIColor blackColor];
l.text=#"Just some randoom text here";
[cell.contentView addSubview:l];
[l release];
return cell;
}
You will want to follow a pattern like this:
#define kTagMyLabel 1
- (UITableViewCell *)tableView:(UITableView *)tableView
cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellID = #"Cell1";
UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellID];
UILabel * l;
if (cell == nil) {
// create the cell
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:cellID] autorelease];
// perform setup/functions that are common to all cells
l = [[[UILabel alloc] initWithFrame:CGRectMake(10,10,300,16)] autorelease];
l.font=[UIFont boldSystemFontOfSize:15];
l.textColor=[UIColor whiteColor];
l.backgroundColor=[UIColor blackColor];
l.tag = kTagMyLabel ;
[cell.contentView addSubview:l];
}
else
{
// find the label we previously added.
l = (UILabel*)[cell viewWithTag:kTagMyLabel];
}
// now set up the cell specific to this indexPath
l.text=#"Just some random text here";
return cell;
}
You're recycling UITableViewCell instances, but you're still creating a new UILabel instance for every row, and adding it to each and every cell. This is where the memory usage comes from. Try something like this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellID = #"Cell";
[self.tableView deselectRowAtIndexPath:indexPath animated:YES];
UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:cellID];
if (cell == nil) {
cell = [[[UITableViewCell alloc] initWithFrame:CGRectZero reuseIdentifier:cellID] autorelease];
UILabel *l=[[UILabel alloc] initWithFrame:CGRectMake(10,10,300,16)];
l.font=[UIFont boldSystemFontOfSize:15];
l.textColor=[UIColor whiteColor];
l.backgroundColor=[UIColor blackColor];
l.text=#"Just some randoom text here";
[cell.contentView addSubview:l];
[l release];
}
return cell;
}
Since every UITableViewCell has its own standard UILabel (cell.textLabel), do you really need that extra label added to the contentView? If you need custom cells, you might want to consider subclassing UITableViewCell.