iOS: Use of undeclared identifiers with NSMutableArray - ios

Question

I am very new to iOS, but I am on the verge of completing my app if I can get this error to go away. I'm experienced in C and C++, but objective-c has been rather confusing to me in the way in which things are done.
Header File:
#interface ThirdTableViewController : UITableViewController<MFMailComposeViewControllerDelegate>
-(id) init;
#property (strong, nonatomic) NSMutableArray *csvFileNames;
#property (strong, nonatomic) NSMutableArray *csvFilePaths;
- (IBAction)refreshTableButton:(id)sender;
- (IBAction)sendEmailButton:(id)sender;
void refreshTable();
#end
Implementation File:
void refreshTable(){
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSArray *documentArray = [[NSFileManager defaultManager] contentsOfDirectoryAtPath:documentsDirectory error:nil];
NSArray *csvFiles = [documentArray filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(NSString *evaluatedObject, NSDictionary *bindings) {
return [evaluatedObject hasSuffix:#".csv"];
}]];
_csvFileNames = csvFiles;
for (NSString *fileName in csvFiles) {
[_csvFilePaths addObject:[documentsDirectory stringByAppendingPathComponent:fileName]];
}
//NSLog(#"files array %#", _fileNamesArray);
//NSLog(#"files array %#", _filePathsArray);
}
I'm getting the errors where my two NSMutableArrays declared in the .h file are used in the .m file. These are the specific lines:
_csvFileNames = csvFiles;
[_csvFilePaths addObject:[documentsDirectory stringByAppendingPathComponent:fileName]];
These are the specific errors: Use of undeclared identifier '_csvFileNames', Use of undeclared identifier '_csvFilePaths'
In C++ if we are to implement a class function we do something like class::myfunction(parameters...). I assume my issue is somewhere along these lines.

Answer 1

The problem is with your refreshTable function. It's a function, not an instance method. Such a function has no access to any instance methods or variable of the class.
In the .h, change:
void refreshTable();
to:
- (void)refreshTable;
Update the .m:
void refreshTable(){
to:
- (void)refreshTable {
Then where ever you call it, change:
refreshTable();
to:
[self refreshTable];
Once you do that you will have other problems. You are attempting to assign an NSArray to a variable of type NSMutableArray. Change this code:
NSArray *csvFiles = [documentArray filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(NSString *evaluatedObject, NSDictionary *bindings) {
return [evaluatedObject hasSuffix:#".csv"];
}]];
_csvFileNames = csvFiles;
for (NSString *fileName in csvFiles) {
[_csvFilePaths addObject:[documentsDirectory stringByAppendingPathComponent:fileName]];
}
to:
NSArray *csvFiles = [documentArray filteredArrayUsingPredicate:[NSPredicate predicateWithBlock:^BOOL(NSString *evaluatedObject, NSDictionary *bindings) {
return [evaluatedObject hasSuffix:#".csv"];
}]];
_csvFileNames = [NSMutableArray array];
for (NSString *fileName in csvFiles) {
[_csvFilePaths addObject:[documentsDirectory stringByAppendingPathComponent:fileName]];
}
Better yet, use your properties:
self.csvFileNames = [NSMutableArray array];
for (NSString *fileName in csvFiles) {
[self.csvFilePaths addObject:[documentsDirectory stringByAppendingPathComponent:fileName]];
}

Answer 2

In your refreshTable method, you declared csvFiles as NSArray and tried to assign it to _csvFileNames which is NSMutableArray.
You can't assign an variable NSArray to a NSMutableArray variable.