cellForRowAtIndexPath Crash [duplicate] - iphone

Question

This question already has answers here:
cellForRowAtIndexPath: crashes when trying to access arrays objectAtIndex:indexPath.row
(2 answers)
Closed 8 years ago.
I have a NSMutable array with data.
I want in the method "cellForRowAtIndexPath" fill the individual rows.
The table view keeps crashing and I do not know why.
The problem is in this line "cell.ergebnissLabel.text = [result objectAtIndex:indexPath.row]".
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
static NSString *CellIdentifier = #"ErgebnisseCell";
ErgebnisseCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier forIndexPath:indexPath];
if (indexPath.section == 0) {
NSDictionary*filtertNew = [self.nummeriertesArray objectAtIndex:0];
NSArray *result = [[filtertNew allKeys] objectAtIndex:1]
cell.ergebnissLabel.text = [result objectAtIndex:indexPath.row];
}
return cell;
}
The error message looks like this.
2014-02-28 17:32:11.208 Info[2451:70b] -[__NSCFString objectAtIndex:]: unrecognized selector sent to instance 0x10950c110
2014-02-28 17:32:11.210 Info[2451:70b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFString objectAtIndex:]: unrecognized selector sent to instance 0x10950c110'
*** First throw call stack:
(
0 CoreFoundation 0x0000000101caf295 __exceptionPreprocess + 165
1 libobjc.A.dylib 0x0000000101a0d99e objc_exception_throw + 43
2 CoreFoundation 0x0000000101d4045d -[NSObject(NSObject) doesNotRecognizeSelector:] + 205
3 CoreFoundation 0x0000000101ca0b8d ___forwarding___ + 973
4 CoreFoundation 0x0000000101ca0738 _CF_forwarding_prep_0 + 120
5 Info 0x000000010001f0da -[ErgebnisseTableViewController tableView:cellForRowAtIndexPath:] + 394
6 UIKit 0x000000010069574a -[UITableView _createPreparedCellForGlobalRow:withIndexPath:] + 348
7 UIKit 0x000000010067bb1b -[UITableView _updateVisibleCellsNow:] + 2337
8 UIKit 0x000000010068cfc1 -[UITableView layoutSubviews] + 207
9 UIKit 0x0000000100621943 -[UIView(CALayerDelegate) layoutSublayersOfLayer:] + 354
10 QuartzCore 0x000000010021cdf2 -[CALayer layoutSublayers] + 151
11 QuartzCore 0x0000000100211959 _ZN2CA5Layer16layout_if_neededEPNS_11TransactionE + 363
12 QuartzCore 0x00000001002117da _ZN2CA5Layer28layout_and_display_if_neededEPNS_11TransactionE + 24
13 QuartzCore 0x00000001001856e4 _ZN2CA7Context18commit_transactionEPNS_11TransactionE + 252
14 QuartzCore 0x000000010018675c _ZN2CA11Transaction6commitEv + 394
15 UIKit 0x00000001005c01f1 _UIApplicationHandleEventQueue + 10863
16 CoreFoundation 0x0000000101c3eb21 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 17
17 CoreFoundation 0x0000000101c3e3f2 __CFRunLoopDoSources0 + 242
18 CoreFoundation 0x0000000101c5a26f __CFRunLoopRun + 767
19 CoreFoundation 0x0000000101c59b83 CFRunLoopRunSpecific + 467
20 GraphicsServices 0x0000000103587df5 GSEventRunModal + 161
21 UIKit 0x00000001005c2003 UIApplicationMain + 1010
22 Info 0x0000000100036143 main + 115
23 libdyld.dylib 0x00000001025a35fd start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
Thanks.

Answer 1

This two line gives you an error:
NSArray *result = [[filtertNew allKeys] objectAtIndex:1]
[result objectAtIndex:indexPath.row];
// This gives you array of string
[filtertNew allKeys]
// This gives you string (second in array)
[[filtertNew allKeys] objectAtIndex:1]
//When you call that line you call
[result objectAtIndex:indexPath.row]
//You call objectAtIndex: method on NSString object but there is not method like that on NSString
I believe you want to do:
cell.ergebnissLabel.text = [[filtertNew allKeys] objectAtIndex:row]

Answer 2

Here's the problem. First, your code obtains an instance of NSDictionary from an array:
NSDictionary *filtertNew = [self.nummeriertesArray objectAtIndex:0];
On the next line, you obtain an array of the dictionary's keys, which in all likelihood are instances of NSString. You then access the second key in the array and store it in a variable named result.
NSArray *result = [[filtertNew allKeys] objectAtIndex:1]
Unfortunately, although the result variable is typed NSArray *, the value you're assigning is a string, not an array. Next, you send objectAtIndex: to that string, which crashes the app because NSString doesn't have an objectAtIndex: method.
cell.ergebnissLabel.text = [result objectAtIndex:indexPath.row];
That's why you're seeing the following error message on the console:
*** Terminating app due to uncaught exception 'NSInvalidArgumentException',
reason: '-[__NSCFString objectAtIndex:]: unrecognized selector sent to instance 0x10950c110'
This tells you that an instance of NSString was sent an objectAtIndex: message, and that since the instance didn't recognize the selector (i.e., the method name), it threw an exception.
However, you haven't included any information on what it is you're trying to do, so i would be difficult to tell you exactly what you'd need to do to get it working correctly.