UITableView displays data then crashes - objective-c

I'm making an iOS that lists the files in the Documents dictionary. I want to display this data in a UITableView, the problem is that it's not working.
It loads the data in to the view. Then the application freezes and calls EXC_BAD_ACCESSThis is my code:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
timesRun = 0;
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectoryPath = [paths objectAtIndex:0];
NSString *bundleRoot = [[NSBundle mainBundle] bundlePath];
dirContents = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:documentsDirectoryPath error:nil];
[bundleRoot release];
NSLog(#"Count: %i",[dirContents count]);
return [dirContents count];
}
- (UITableViewCell *)tableView:(UITableView *)tableViewData cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = nil;
int Locatation = indexPath.row;
Locatation++;
cell = [tableViewData dequeueReusableCellWithIdentifier:#"MyCells"];
if (cell == nil) {
cell = [[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"MyCell"]autorelease];
}
//cell.textLabel.text = [NSString stringWithFormat:#"Cell: %i",Locatation];
cell.textLabel.text = [dirContents objectAtIndex:timesRun];
timesRun++;
return cell;
NSLog(#"Did return");
}
- (void)tableView:(UITableView *)tableViewDat didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
NSLog(#"%#",cell.textLabel.text);
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}

This displays a basic misunderstanding of the concept of the table view data source.
My suggestion:
Create an array that contains the files outside any tableview methods. Then you use that array to feed the tableview.
Use array.count to return numberofrowsatindexpath.
Also, on providing the cells at cellforrowatindexpath, don't use iterations/counters. The tableview ask for each element of your array itself using the indexpath argument. You access it like this:
id object = [array objectArIndex: indexPath.row]
And you then use the objects attributes to set the labels of the cell.
Please read a tutorial on tableviews. I recommend itunesU Paul hegarty's lectures. They're really great.
Ps. You release the bundleRoot object in numberofrowsinsection, which you don't retain (or use at all) which is most likely causing your crash.
Edit:
With a little more spare time, I retouched your code:
//code not tested/written in xcode. Might contain typos
//in your .m file
//in your (private) interface
#property (nonatomic, retain, readonly) NSArray *dirContents;
//in your implementation
#synthesize dirContents=_dirContents;
-(NSArray*) dirContents {
if (!dirContents) {
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectoryPath = [paths objectAtIndex:0];
_dirContents = [[[NSFileManager defaultManager] contentsOfDirectoryAtPath:documentsDirectoryPath error:nil] retain];
}
return _dirContents;
//note that if you want to "refresh" the contents you would have to
//release _dirContents and set it to nil or implement this differently
}
-(void) dealloc {
[_dirContents release];
//....
[super dealloc];
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section{
return [[self dirContents] count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{
UITableViewCell *cell = nil;
cell = [tableView dequeueReusableCellWithIdentifier:#"MyCells"];
if (cell == nil) {
cell = [[[UITableViewCell alloc]initWithStyle:UITableViewCellStyleDefault reuseIdentifier:#"MyCells"]autorelease];
}
cell.textLabel.text = [[self dirContents] objectAtIndex: indexPath.row];
return cell;
//  NSLog(#"Did return"); //this never gets called by the way
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
NSLog(#"%#",cell.textLabel.text);
[tableView deselectRowAtIndexPath:indexPath animated:YES];
}

My problem was sort of like Mario's answer. [dirContents count] returned a higher value than the amount of times it could add an object from the array.In other words it was a Out of Bounds error.

Make sure you are not releasing dirContents while using that.I am sure you are not doing but just cross check with your code.

Related

UISearch and TableViewCell

When I searching and then select row that opens only the first letter (for example A.Others letters don't open. NSLog and breakpoint not helping. I don't understand what is the problem.
#synthesize propertyList, letters, filteredNames, searchController , arrayPlace;
- (void)viewDidLoad {
[super viewDidLoad];
............
filteredNames = [[NSMutableArray alloc]init];
searchController = [[UISearchController alloc]init];
self.searchController.searchResultsUpdater = self;
NSString *path = [[NSBundle mainBundle] pathForResource:#"names" ofType:#"plist"];
self.propertyList = [NSDictionary dictionaryWithContentsOfFile:path];
self.letters = [[self.propertyList allKeys] sortedArrayUsingSelector:#selector(compare:)];
}
#pragma mark - Table view data source
.......
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
cell.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"cell bg1.png"]];
cell.accessoryType = UITableViewCellAccessoryDetailDisclosureButton;
if (tableView.tag == 1){
NSString *letter = self.letters[indexPath.section];;
NSArray *keyValues = [[self.propertyList[letter] allKeys] sortedArrayUsingSelector:#selector(compare:)];
cell.textLabel.text = keyValues[indexPath.row];
} else{
cell.textLabel.text = filteredNames[indexPath.row];
}
return cell;
}
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
NSString *keyTitle = cell.textLabel.text;
NSDictionary *peopleUnderLetter = [self.propertyList objectForKey:self.letters[indexPath.section]];
__block NSDictionary *selectedPerson = nil;
[peopleUnderLetter enumerateKeysAndObjectsUsingBlock:^(id _Nonnull key, id _Nonnull obj, BOOL * _Nonnull stop) {
if ([key isEqualToString:keyTitle]) {
selectedPerson = obj;
*stop = YES;
}
}];
if (selectedPerson) {
DetailViewController *vc = [self.storyboard instantiateViewControllerWithIdentifier:#"DetailViewController"];
// Push the view controller.
[self.navigationController pushViewController:vc animated:YES];
[vc setDictionaryGeter:selectedPerson];
}
}
And :
#pragma mark Search Display Delegate Methods
-(void)searchDisplayController:(UISearchController *)controller didLoadSearchResultsTableView:(UITableView *)tableView {
[tableView registerClass:[UITableViewCell class] forCellReuseIdentifier:#"Cell"];
}
-(BOOL)searchDisplayController:(UISearchController *)controller shouldReloadTableForSearchString:(NSString *)searchString
{
[filteredNames removeAllObjects];
if (searchString.length > 0) {
NSPredicate *predicate = [NSPredicate predicateWithFormat:#"SELF contains [search] %#", self.searchBar.text];
for (NSString *letter in letters) {
NSArray *matches = [[self.propertyList[letter] allKeys]filteredArrayUsingPredicate:predicate];
[filteredNames addObjectsFromArray:matches];
}
}
return YES;
}
Search bar fails and he does select row after searching
If you want more information just say it to me by answers and I will edit my question and then you will edit your answer
Please explain again clearly. You search using any alphabet, it shows the result which has only "A". Is this what you're trying to say ? If so, then remove the above code and try the below approach :-
Drag a search bar into the view controller and set its delegate to self (You'll find its property in the storyboard's delegate property
to the view controller).
Add UISearchBarDelegate in the .h file that will take care of automatically calling the appropriate methods of the search bar of
which the delegate is set to self.
Use the below method to detect the search. You can filter the NSArray here and reload the table.
-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText{
}
I'd recommend you to go through some basic tutorials about iOS development before getting deeper. All the best and I hope it helps you...
Screenshot

Displaying data retrieved from Parse in UITableView

After all progress i made with your answers, my issue changed. So i am changing my question with clearer way. I have an UITableView which is showing my retrieved data from Parse.com. So i made a NSMutableArray for adding objects to that array when they are retrieved. But my problem is even i add objects to NSMutableArray, my table does not show anything but default screen of UITableView. I thing the issue is UITableView is formed before my NSMutableArray got its objects. Here is my code:
Note: The PropertyClass is the class which has the properties of my objects.
At MyTableViewController.h
#interface MyTableViewController : UITableViewController <CLLocationManagerDelegate> {
PFObject *object;
}
#property (strong, nonatomic) IBOutlet UITableView *MyTableView;
#end
At UITableViewController.m
#interface MyTableViewController ()
#property(strong)NSMutableArray *myNSMutableArray;
#end
#implementation MyTableViewController
#synthesize myNSMutableArray,MyTableView;
-(void) retrievingDataFromParse{
PFQuery *query = [PFQuery queryWithClassName:#"MyObjectsClass"];
[query whereKey:#"ObjectsNumber" lessThanOrEqualTo:10];
[query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
if (!error) {
// The find succeeded.
NSLog(#"Successfully retrieved %d scores.", objects.count);
if (objects.count==0) {
NSString *objectError = #"There no object retrieved from Parse";
PropertiesClass *PC = [[PropertiesClass alloc]initWithPropert1:objectError Propert2:nil Propert3:nil Propert4:nil];
[myNSMutableArray addObject:PC];
}
for (int i = 0; i < objects.count; i++) {
object = [objects objectAtIndex:i];
NSString *Propert1 = [object objectForKey:#"Propert1"];
NSNumber *Propert2 = [object objectForKey:#"Propert2"];
NSNumber *Propert3 = [object objectForKey:#"Propert3"];
NSString *Propert4 = [object objectForKey:#"Propert4"];
PropertiesClass *PC = [[PropertiesClass alloc]initWithPropert1:Propert1 Propert2:Propert2 Propert3:Propert3 Propert4:Propert4];
[myNSMutableArray addObject:PC];
};
} else {
// Log details of the failure
NSLog(#"Error: %# %#", error, [error userInfo]);
}
}];
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.myNSMutableArray = [NSMutableArray array];
[self retrievingDataFromParse];
[MyTableView reloadData];
}
- (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 [myNSMutableArray count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
PropertiesClass *PC= [myNSMutableArray objectAtIndex:indexPath.row];
cell.textLabel.text=PC.Propert1;
return cell;
}
Looking at your code i see that you never create a UITableViewCell, you should change this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
PropertyClass *PC = [myMutableArray objectAtIndex:indexPath.row];
cell.textLabel.text = PC.x;
return cell;
}
with this:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
if (nil == cell){
cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
PropertyClass *PC = [myMutableArray objectAtIndex:indexPath.row];
cell.textLabel.text = PC.x;
return cell;
}
the method dequeueReusableCellWithIdentifier:forIndexPath: return a UITableViewCell only if there are unused, but already allocated, cells in your table view. otherwise it returns nil.
Also when you update the mutable array containing all your data you should call [yourTableView reloadData] to force the table view to reload its content.
Your code is quite cryptic. Few suggestions here.
First, rename variables and methods with camelCaseNotation (camel case notation). For example, MyMutableArray should be myMutableArray. RetrievingDataFromParse should be retrievingDataFromParse (and so on). Start upper case letter are for classes.
Second, what does this code mean (I put comment on your code)?
for (int i = 0; i < objects.count; i++) {
// where do you have defined object?
object = [objects objectAtIndex:i];
NSString *x = [object objectForKey:#"x"];
NSNumber *y = [object objectForKey:#"y"];
NSNumber *z = [object objectForKey:#"z"];
NSString *t = [object objectForKey:#"t"];
// is Mekan a subclass of PropertiyClass or what else?
PropertiyClass *Properties = [[Mekan alloc]initWithx:x y:y z:z t:t]
// what's MekanKalibi? Maybe you need to add Properties
[MyMutableArray addObject:MekanKalibi];
}
Edit
If you don't use iOS6 - (void)registerClass:(Class)cellClass forCellReuseIdentifier:(NSString *)identifier you should alloc-init cells.
static NSString *CellIdentifier = #"Cell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
if(!cell) {
// alloc-init a new cell here...
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
// or if you don't use ARC
// cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
PropertyClass *PC = [myMutableArray objectAtIndex:indexPath.row];
cell.textLabel.text = PC.x;
return cell;
Edit 2
I don't know how parse works but I suppose it manages async requests. So, at the end of your for loop, just call reload data in the table.
Parse states:
The InBackground methods are asynchronous, so any code after this will run immediately. Any code that depends on the query result should be moved inside the completion block above.
I had the same problem. When you reload the table, you need to move it so it is inside the block. Worked for me.
I'm not 100% sure how the asynchronous parts affect it so. I know that the start of my viewDidload and the end occured then this block, hence the problem.
People should probably up this as this solves the issue.
Cheers.
All you have to do is reload tableView in the block... this will show data.
for (int i = 0; i < objects.count; i++) {
object = [objects objectAtIndex:i];
NSString *Propert1 = [object objectForKey:#"Propert1"];
NSNumber *Propert2 = [object objectForKey:#"Propert2"];
NSNumber *Propert3 = [object objectForKey:#"Propert3"];
NSString *Propert4 = [object objectForKey:#"Propert4"];
PropertiesClass *PC = [[PropertiesClass alloc]initWithPropert1:Propert1 Propert2:Propert2 Propert3:Propert3 Propert4:Propert4];
[myNSMutableArray addObject:PC];
};
} else {
// Log details of the failure
NSLog(#"Error: %# %#", error, [error userInfo]);
}
**[MyTableView reloadData];**
}];

When scrolling in my UITableView cells are disappearing

This is my sample twitter program it works but there are several errors
if I scroll up or down top and bottom cellls disappears some times I get an error saying :
BAD ACCESS CODE this happens on this row
NSDictionary *tweet = [tweets objectAtIndex:indexPath.row];
Please Advice
#import "TableViewViewController.h"
#interface TableViewViewController ()
#end
#implementation TableViewViewController
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"tweets array count : %d", tweets.count);
return tweets.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"TweetCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
NSLog(#"ROW : %d", indexPath.row);
NSDictionary *tweet = [tweets objectAtIndex:indexPath.row];
NSString *text = [tweet objectForKey:#"text"];
NSString *name = [[tweet objectForKey:#"user"] objectForKey:#"name"];
cell.textLabel.text = text;
cell.detailTextLabel.text = [NSString stringWithFormat:#"by %#", name];
return cell;
}
- (void)viewDidLoad
{
[super viewDidLoad];
[self fetchTweets];
}
- (void)fetchTweets
{
NSString *twitterURL = [NSString stringWithFormat:#"https://api.twitter.com/1/statuses/public_timeline.json"];
NSURL *fullURL = [NSURL URLWithString:twitterURL];
NSError *error = nil;
NSData *dataURL = [NSData dataWithContentsOfURL:fullURL options:0 error:&error];
tweets = [NSJSONSerialization JSONObjectWithData:dataURL
options:kNilOptions
error:&error];
}
.....
#end
I see problems in this function:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
NSLog(#"tweets array count : %d", tweets.count);
//return tweets.count;
return 11; //default returns 20 but only shows 10 indexpath.Row so 11
}
You probably shouldn't be just returning 11 -- what if tweets has a different length? The table view will try to fetch a cell at an index which doesn't exist in your array. Try returning tweets.count instead.
To elaborate a bit further: The purpose of the tableView:numberOfRowsInSection: method isn't to tell iOS how many rows there are on the screen, it's how many rows there are in the entire tableView. This includes cells which aren't shown on screen.
Found out the answer My app doesn't support ARC because I didn't check if we use a retain at the NSJSONSerialization the error is fixed.
tweets = [[NSJSONSerialization JSONObjectWithData:dataURL
options:kNilOptions
error:&error] retain];
Why is numberOfRowsInSection hardcoded to 11?
Also you should have [self.tableView reloadData] after the tweets array is set up in fetchTweets
Why don't you just uncomment return tweets.count; in your numberOfRowsInSection method?

Custom cell not showing up in tableView

I have a custom cell with identifyer 'tweetCell' I have imported this into my tableviewcontroller.h file. I have linked the class to the prototype cell in storyboard. All the UILabels are wired up to the cell but I cannot get the tableview to display the custom cell. It did work? Then overnight stopped?!! I understand that class files need to start with an upper case letter, I have changed this but to no avail. Can anyone spot my error here? Thanks in advance......
- (void)fetchTweets
{
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
NSData* data = [NSData dataWithContentsOfURL:
[NSURL URLWithString: #"http://search.twitter.com/search.json?q=%23mysearchhashtag"]];
NSError* error;
tweets = [NSJSONSerialization JSONObjectWithData:data
options:kNilOptions
error:&error];
dispatch_async(dispatch_get_main_queue(), ^{
[self.tableView reloadData];
});
});
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return tweets.count;
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = #"tweetCell";
customCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[customCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
NSDictionary *tweet = [tweets objectAtIndex:indexPath.row];
NSString *tweetText = [tweet valueForKey:#"text"];
NSArray *tweetComponents = [tweetText componentsSeparatedByString:#":"];
cell.firstDetail.text = [tweetComponents objectAtIndex:0];
cell.secondDetail.text = [tweetComponents objectAtIndex:1];
cell.thirdDetail.text = [tweetComponents objectAtIndex:2];
return cell;
}
Did you write this method - (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView? Try like this.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
return 1;
}

UITableView to detail UITableView drill down using storyboard

I am trying to develop a RSS Reader drill down table with storyboard in a Tab bar app. I have managed to populate my RootTableViewController with the parsed XML. I am now having a problem working out how to get each row in my RootTableViewController to point and to pass the data from the selected cell to another DetailTableViewController.
This is part of my code to parse the XML and to populate the RootTableViewController:
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
return [stories count];
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"AdvCurrentCelly";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
}
int storyIndex = [indexPath indexAtPosition: [indexPath length] - 1];
NSString *description = [[stories objectAtIndex: storyIndex] objectForKey: #"description"];
NSString *title = [[stories objectAtIndex: storyIndex] objectForKey: #"title"];
//This populates the prototype cell 'AdvCurrentCelly'
cell.textLabel.text = title;
//cell.textLabel.text = date;
cell.detailTextLabel.text = description
return cell;
}
In Storyboard, the name of the segue from the RootTableViewContoller cell to the DetailTableViewController is ShowADVDetail
Help much appreciated
Jan
You can pass any type of data, but I'll show you how to pass your Title string. Lets call it myString. First you need to add a property in your DetailTableViewController.h to store your string:
#property (strong, nonatomic) NSString *myString
In you RootTableViewController you need to tell the segue what to do. Use this code as an example:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
// Refer to the correct segue
if ([[segue identifier] isEqualToString:#"ShowADVDetail"]) {
// Reference to destination view controller
DetailTableViewController *vc = [segue destinationViewController];
// get the selected index
NSInteger selectedIndex = [[self.teamTable indexPathForSelectedRow] row];
// Pass the title (from your array) to myString in DetailTableViewController:
vc.myString = [NSString stringWithFormat:#"%#", [[stories objectAtIndex:selectedIndex] objectForKey: #"Title"]];
}
}