iosobjective-cuitableviewuibuttonnsuserdefaults

Reputation: 21

App crashes when button is pressed that points to table view

I've got a button pointing to a view and whenever I see press the button my app crashes. Can anyone tell me why? The code is the implementation file for the view that the button pushes to.

@implementation OpenShiftViewController

-(void)viewDidLoad
{
    [super viewDidLoad];
    NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
    myDictionary = [defaults dictionaryRepresentation];
}

-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView 
{
    return 1; 
}

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    return myDictionary.count; 
}

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath 
{
    static NSString *CellIdentifier = @"cell";
    UITableViewCell *cell = (UITableViewCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    NSArray * allKeys = [myDictionary allKeys];
    cell.textLabel.text = [myDictionary objectForKey:[allKeys objectAtIndex:indexPath.row]];
    cell.detailTextLabel.text = [myDictionary objectForKey:[allKeys     objectAtIndex:indexPath.row]];
    return cell; 
}

@end

Upvotes: 0

Answers (5)

BooRanger

Reputation: 1526

Like everyone else I would like to point out that should post your error.

Now I also see one problem with cellAtindexPath logic. Your trying to set data on null cell, see [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; will only give you something back if you've already given it something.

You've two options for loading a cell, the new way or the old way, both are kinda of same.

Option one and I recommend this one:

in your viewDidLoad (or what not) register a class for a cell identifer:

[self.tableview registerClass:[UITableViewCell class] forCellReuseIdentifier:@"cell"];

In CellForIndexPath to get the cell go:

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell" forIndexPath:indexPath];

The forIndexPath is important here, using old api will return a nil cell.

Option 2:

Load a cell and if its nil, create a it.

UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];
if (!cell) {
  cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:@"cell"];

}

Upvotes: 0

Arun Kumar

Reputation: 798

- (void)viewDidLoad

{

[super viewDidLoad];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
myDictionary = [defaults dictionaryRepresentation];


myMutableArray = [[NSMutableArray alloc]init];
[self storingObjectsFromDictionaryToArray];
// Do any additional setup after loading the view, typically from a nib.

}

-(void)storingObjectsFromDictionaryToArray

{

NSArray *arr = [myDictionary allKeys];


  [myMutableArray addObjectsFromArray:[myDictionary valueForKey:[arr objectAtIndex:0]]];
NSString *str = [NSString stringWithFormat:@"%@",[myDictionary valueForKey:[arr objectAtIndex:1]]];
[myMutableArray addObject:str];
str = [NSString stringWithFormat:@"%@",[myDictionary valueForKey:[arr objectAtIndex:2]]];
[myMutableArray addObject:str];
 [myMutableArray addObjectsFromArray:[myDictionary valueForKey:[arr objectAtIndex:3]]];
 [myMutableArray addObject:[myDictionary valueForKey:[arr objectAtIndex:4]]];
 [myMutableArray addObjectsFromArray:[myDictionary valueForKey:[arr objectAtIndex:5]]];
 [myMutableArray addObjectsFromArray:[myDictionary valueForKey:[arr objectAtIndex:6]]];
 [myMutableArray addObject:[myDictionary valueForKey:[arr objectAtIndex:7]]];

}

-(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView

{

return 1;

}

-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section

{

return myMutableArray.count;

}

-(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.textLabel.text = [myMutableArray objectAtIndex:indexPath.row];
cell.detailTextLabel.text = [myMutableArray objectAtIndex:indexPath.row];


return cell;

}

Upvotes: 1

Traze

Reputation: 180

As AlexVogel pointed out in the comments, use init method to initialize the dictionary. Alternatively, you can use lazy loading using property:

- (NSDictionary *)myLoadedDictionary{
    if (!myDictionary) {
        NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
        myDictionary = [defaults dictionaryRepresentation];
    }
    return myDictionary;
}

Now, in your class, consume [self myLoadedDictionary] instead of myDictionary.

I am not on my machine, but I am pretty much sure that you can define even myDictionary as a getter so that you can use that same name in your code and not myLoadedDictionary.

Upvotes: 0

Arun Kumar

Reputation: 798

You are not getting an error - it is just cause of you having an activated breakpoint.

If you're using Xcode 4, then you can see 'Breakpoints' as seen below. Just click on that to disable breakpoints.

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