Problem adding custom objects to Mutable Array - iphone

quick question regarding Array's in xcode. I have ht efollowing code, which is supposed to go through an array of strings which it has got through php and JSON, and trun these strings into a custom object with the strings as the ivars for the object then add that object to a new array:
for (int i = 0; i<[list count]; i++) {
Article *article = [[Article alloc] init]; //creates custom object
article.uid = [[list objectAtIndex:i] objectAtIndex:0];
article.title = [[list objectAtIndex:i] objectAtIndex:1]; //adds string as ivars
article.description = [[list objectAtIndex:i] objectAtIndex:2];
articleArray = [[NSMutableArray alloc] init]; //inits the new array
[articleArray addObject:article]; //should add the object but seems to fail
[article release]; //releases the object
NSLog(#"%#", article.description);
}
NSLog(#"%d", [articleArray count]);
NSLog([articleArray description]);
}
The code does return the correct values using NSLog(#"%#", article.description); but not the correct length for the new array and it only adds one value to the array which is the string for article.description which makes no sense to me. The list array contains 2 elements each of which are arrays in themselves containing the strings.

You're recreating the articleArray in every loop. Declarate it outside, and it will work:
NSMutableArray *articleArray = [[NSMutableArray alloc] init]; //inits the new array
for (int i = 0; i<[list count]; i++) {
Article *article = [[Article alloc] init]; //creates custom object
article.uid = [[list objectAtIndex:i] objectAtIndex:0];
article.title = [[list objectAtIndex:i] objectAtIndex:1]; //adds string as ivars
article.description = [[list objectAtIndex:i] objectAtIndex:2];
[articleArray addObject:article]; //should add the object but seems to fail
[article release]; //releases the object
NSLog(#"%#", article.description);
}
NSLog(#"%d", [articleArray count]);
NSLog([articleArray description]);
}
You also may want to use the nicer for(NSArray *listElement in list) syntax instead.

Related

iphone: addObjectsFromArray not adding after reinitializing nsmutable array

i have the following code
inAppKeys = [[MKStoreManager sharedManager] purchasableObjectsDescription ];
NSMutableArray * unremovableArray = [[NSMutableArray alloc] init];
for(int i = 0; i<[inAppKeys count]; i++){
for (int j=0; j< [categories count]; j++) {
NSString * inAppKey = [[categories objectAtIndex:j] valueForKey:#"inAppKey"];
if([inAppKey isEqualToString: [inAppKeys objectAtIndex:i]]){
[unremovableArray addObject:[categories objectAtIndex:j]];
}
}
}
categories = [[NSMutableArray alloc] init];
[categories addObjectsFromArray:unremovableArray];
where categories is nsmutablearray .. the thing is addObjectsFromArray leave the categories empty .. what do i do wrong?
Looks to me like you're referring to [categories count] and [categories objectAtIndex:j] before you even alloc/init categories.
Having re-read your title ("reinitializing") which suggests you've previously inited categories, I'm now assuming that you have a master set of categories that you're trying to reduce to the ones actually purchased. If so, I wouldn't re-use the variable "categories" as that's confusing. (I assume categories was auto-released, or else you've got a leak). How 'bout using unremovableArray instead of leaking it?
I'd also use fast enumerators for clarity and speed...
NSLog(#"categories: %#", categories);
inAppKeys = [[MKStoreManager sharedManager] purchasableObjectsDescription ];
NSLog(#"inAppKeys:%#", inAppKeys);
NSMutableArray * unremovableCategories = [[NSMutableArray alloc] init];
for(NSString* thisAppKey in inAppKeys) {
for (NSDictionary* thisCategory in categories) {
if ([[thisCategory valueForKey:#"inAppKey"] isEqualToString: thisAppKey]){
[unremovableCategories addObject:thisCategory];
break; //having added this category; no reason to continue looking at it
}
}
}
//now use unremovableCategories...

how to create an array of string or float in Objective-C

i need some help here, i need to know how to create an array of string retrieved from an array. i'm using powerplot for graph and it only accept float or string array.
i need to create something something like this dynamically.
NSString * sourceData[7] = {#"2", #"1", #"4", #"8", #"14", #"15", #"10"};
Below are my code to find out the numbers in strings.
NSInteger drunked = [appDelegate.drinksOnDayArray count];
NSMutableArray * dayArray = [[NSMutableArray alloc] init];
NSMutableArray * sdArray = [[NSMutableArray alloc] init];
//float *sdArray[7];
for (int i=0; i<drunked; i++) {
DayOfDrinks *drinksOnDay = [appDelegate.drinksOnDayArray objectAtIndex:i];
NSString * dayString= [NSDate stringForDisplayFromDateForChart:drinksOnDay.dateConsumed];
[dayArray addObject:dayString];
NSLog(#"%#",[dayArray objectAtIndex:i]);
drinksOnDay.isDetailViewHydrated = NO;
[drinksOnDay hydrateDetailViewData];
NSString * sdString= [NSString stringWithFormat:#"%#", drinksOnDay.standardDrinks];
[sdArray addObject:sdString];
NSString *tempstring;
NSLog(#"%#",[sdArray objectAtIndex:i]);
}
thanks for the help :)
Array's in Objectice-C aren't that hard to work with:
NSMutableArray *myArray = [NSMutableArray array];
[myArray addObject:#"first string"]; // same with float values
[myArray addObject:#"second string"];
[myArray addObject:#"third string"];
int i;
int count;
for (i = 0, count = [myArray count]; i < count; i = i + 1)
{
NSString *element = [myArray objectAtIndex:i];
NSLog(#"The element at index %d in the array is: %#", i, element); // just replace the %# by %d
}
You can either use NSArray or NSMutableArray - depending on your needs, they offer different functionality.
Following tutorial covers exactly what you are looking after:
http://www.cocoalab.com/?q=node/19
You can also add the elements to the array when you init (and optionally add them later only if you are using the Mutable version of a collection class:
NSMutableArray *myArray = [[NSMutableArray alloc] initWithObjects:#"2", #"1", #"4", #"8", #"14", #"15", #"10", nil];
[myArray addObject:#"22"];
[myArray addObject:#"50"];
//do something
[myArray release];
You can use malloc to create a C-style array. something like this should work:
NSString **array = malloc(numElements * sizeof(NSString *))
some code here
free(array)
Be aware that unlike NSMutable array, c arrays won't do a retain, so you have to manage it if needed. And don't forget the free

Problem with arrays (add and copy)

I've got a problem. I'm trying to sort the items from 1 array (name: mps) into an other array (name: totalArray), but every item should be in a new array. In short: the items in mps should move into a new array, but every item should be in a new array, so the totalArray is an array of arrays. After that, totalArray should be copied back into mps.
To clarify, here is the code:
NSMutableString *oud = [[NSMutableString alloc] init];
NSMutableString *nieuw = [[NSMutableString alloc] init];
NSMutableArray *tempArray = [[NSMutableArray alloc] init];
[tempArray removeAllObjects];
NSMutableArray *totalArray = [[NSMutableArray alloc] init];
[totalArray removeAllObjects];
tempArray = [[NSMutableArray alloc] init];
[tempArray removeAllObjects];
for (int j = 0; j < [mps count]; j++)
{
nieuw = [[mps objectAtIndex:j] valueForKey:#"ConfigurationAlias"];
if (j != 0)
{
if ([oud rangeOfString:nieuw].location == NSNotFound)
{
NSLog(#"ADDED!");
[totalArray addObjectsFromArray:tempArray];
[oud setString:nieuw];
[tempArray removeAllObjects];
[tempArray addObject:[mps objectAtIndex:j]];
}
else
{
[tempArray addObject:[mps objectAtIndex:j]];
}
}
else {
[oud setString:nieuw];
[tempArray addObject:[mps objectAtIndex:j]];
}
}
//En de array weer laden in de tabel
//NSLog(#"%#", totalArray);
NSLog(#"%i", [mps count]);
[mps removeAllObjects];
NSLog(#"REMOVED!!!");
NSLog(#"%i", [mps count]);
[mps addObjectsFromArray:totalArray];
NSLog(#"Added totalArray: %i", [totalArray count]);
NSLog(#"%i", [mps count]);
[tempArray release];
[totalArray release];
[tabelView reloadData];
}
Now, here comes my problem:
The log gives the line 2011-04-07 10:02:46.368 Fleet Manager[901:40b] ADDED! 11 times, then it posts 16 (mps count, this is correct), then the line REMOVED!, then 0 (mps count, also correct), but then the line: Added totalArray: 15. This can't be correct, it added 11 times but it counts 15?
This a problem for me, in the first place because it's plain incorrect, but the tableview gets screwed up as well because of the section-amount not being correct either (15 sections). Anybody has any idea what's going on?
EDIT: all the objects in mps are dictionaries, and all of them have a value for the key "ConfigurationAlias".
First, I would like to suggest using debugging mode instead of bunch of NSLog functions to track down what's actually happening inside your objects and variables. Try using breakpoints. Set one for [totalArray addObjectsFromArray:tempArray]; line so every time this line of code is reached the execution would stop and let you look around, check different fields' states inside totalArray and tempArray objects.
Concerning your problem... Since you are using addObjectsFromArray: that means that passed array may pass not one but several objects (thus the plural in method name). I guess one of those "11 times" added more than one element - that should explain the actual count being more than the times you've called this method. Again, please check tempArray contents.
Good luck!
If you want to end up with an array of arrays, you need to be allocating temp arrays inside the loop. It also seems like you are overdoing it with clearing out the arrays.
It appears you are trying to add the value from mps to totalArray regardless of the conditions, so it would make sense to only do that in one place (outside of the conditions).
Also, if you are not mutating the arrays (such as tempArray), you can use NSArray instead, which should be smaller and faster.
Finally, you should be able to assign the new array to mps instead of doing the expensive array copying. Not sure if that is somehow referenced as the table delegate, though.
I would try something like:
NSMutableString *oud = [[NSMutableString alloc] init];
NSMutableString *nieuw = [[NSMutableString alloc] init];
NSMutableArray *tempArray;
NSMutableArray *totalArray = [[NSMutableArray alloc] init];
for (int j = 0; j < [mps count]; j++)
{
tempArray = [[NSMutableArray alloc] init];
[totalArray addObject:tempArray];
[tempArray release];
nieuw = [[mps objectAtIndex:j] valueForKey:#"ConfigurationAlias"];
if (j != 0)
{
if ([oud rangeOfString:nieuw].location == NSNotFound)
{
NSLog(#"ADDED!");
[oud setString:nieuw];
}
}
else {
[oud setString:nieuw];
}
}
NSLog(#"%i", [mps count]);
[mps removeAllObjects];
NSLog(#"REMOVED!!!");
NSLog(#"%i", [mps count]);
[mps addObjectsFromArray:totalArray];
NSLog(#"Added totalArray: %i", [totalArray count]);
NSLog(#"%i", [mps count]);
[totalArray release];
[tabelView reloadData];
}
You should
sort the base array in a tempArray
create an empty resultArray
iterate through tempArray and for each item create an itemArray containing the item on the first position and add this array to resutArray
don't forget to release all alloc-ed temporary data
Check this out for sorting easily: Sorting arrays via Apple

Converting table view to have sections

I have a table view, which has its data source from an array that contains names of people.
Now to make it easy to find people, I want to section the table view so that it has the letter A-Z on the right hand side, just like the Address Book app.
But my current array just contains a collection of NSStrings. How do I split them so that they are grouped by the first letter of the names? Is there any convenient way to do it?
EDIT: If anyone's interested in my final code:
NSMutableArray *arrayChars = [[NSMutableArray alloc] init];
for (char i = 'A'; i <= 'Z' ; i++) {
NSMutableDictionary *characterDict = [[NSMutableDictionary alloc]init];
NSMutableArray *tempArray = [[NSMutableArray alloc] init];
for (int k = 0; k < [myList count]; k++) {
NSString *currentName = [[friends objectAtIndex:k] objectForKey:#"name"];
char heading = [currentName characterAtIndex:0];
heading = toupper(heading);
if (heading == i) {
[tempArray addObject:[friends objectAtIndex:k]];
}
}
[characterDict setObject:tempArray forKey:#"rowValues"];
[characterDict setObject:[NSString stringWithFormat:#"%c",i] forKey:#"headerTitle"];
[arrayChars addObject:characterDict];
[characterDict release];
[tempArray release];
}
At the end of the function I'll have:
arrayChars [0] = dictionary(headerTitle = 'A', rowValues = {"adam", "alice", etc})
arrayChars[1] = dictionary(headerTitle = 'B', rowValues = {"Bob", etc})
Thank you everyone for your help!
You can use a dictionary to sort them, so create an array with all the letters you want to sort and a array with nil objects to initialize the dictionary
NSArray *names = #[#"javier",#"juan", #"pedro", #"juan", #"diego"];
NSArray *letters = #[#"j", #"p", #"d"];
NSMutableArray *objects = [[NSMutableArray alloc] init];
for (NSInteger i = 0; i < [letters count]; ++i)
{
[objects addObject:[[NSMutableArray alloc] init]];
}
NSDictionary *dictionary = [[NSDictionary alloc] initWithObjects:objects forKeys:letters];
Then you must find the first letter if the word and put that word into the corresponding key in the dictionary
for (NSString *name in names) {
NSString *firstLetter = [name substringToIndex:1];
for (NSString *letter in letters) {
if ([firstLetter isEqualToString:letter]) {
NSMutableArray *currentObjects = [dictionary objectForKey:letter];
[currentObjects addObject:name];
}
}
}
To check you can print directly the dictionary
NSLog(#"%#", dictionary);
Then is your work to fill your sections in the tableview using the dictionary

NSArray objects go out of scope after returning pointer

I am attempting to use the below code in a function to return an array of dictionary objects. Unfortunately, after the return to the next function in the stack all of the rows in the mutable array have become 'out of scope'. From my understanding, the array should retain the row (dictionary) object automatically so even after the return, where the row pointer goes out of scope, the row objects should still have a retain count of 1. What am I doing wrong here? How do I build this array in such a way that the objects it contains don't get released?
for (int i = 1; i < nRows; i++)
{
NSMutableDictionary* row = [[[NSMutableDictionary alloc] initWithCapacity:nColumns] ];
for(int j = 0; j < nColumns; j++)
{
NSString* key = [[NSString stringWithUTF8String:azResult[j]] ];
NSString* value = [[NSString stringWithUTF8String:azResult[(i*nColumns)+j]] ];
[row setValue:value forKey:key];
}
[dataTable addObject:row];
}
return dataTable;
This line:
NSMutableDictionary* row = [[NSMutableDictionary alloc] initWithCapacity:nColumns] ];
should use the autorelease:
NSMutableDictionary* row = [[[NSMutableDictionary alloc] initWithCapacity:nColumns] ] autorelease];
From what i understand:
-(NSMutableArray*) getArrayOfDictionaries{
int nRows=somenumber;
int nColumns=someOthernumber;
char **azResult=someArrayOfStrings;
NSMutableArray *dataTable=[[NSMutableArray alloc] init];
for (int i = 1; i < nRows; i++)
{
NSMutableDictionary* row = [[[NSMutableDictionary alloc] initWithCapacity:nColumns]];
for(int j = 0; j < nColumns; j++)
{
NSString* key = [[NSString stringWithUTF8String:azResult[j]] ];
NSString* value = [[NSString stringWithUTF8String:azResult[(i*nColumns)+j]] ];
[row setValue:value forKey:key];
}
[dataTable addObject:row];
//you should add the following line to avoid leaking
[row release];
}
//watch for leaks
return [dataTable autorelease];
//beyond this point dataTable will be out of scope
}
-(void) callingMethod {
//dataTable is out of scope here, you should look into arrayOfDictionaries variable
NSMutableArray* arrayOfDictionaries=[self getArrayOfDictionaries];
}
You should look into the local variable in callingMethod instead of dataTable which is local to the method I called getArrayOfDictionaries