NSArray losing value at the end of method - ios

I have a project I am working on, to learn some more about JSON and restkit. It all is working great, however I am having trouble with an array losing it's values.
This is the last method that is executed in my network request.
SHRetrieveStoresWS.m
- (void)objectLoader:(RKObjectLoader *)objectLoader didLoadObjects:(NSArray *)objects
{
self.stores = [[NSArray alloc] initWithArray:objects];
StoresViewController *viewController = [[StoresViewController alloc] init];
[viewController didLoadObjects:objects];
for (Store *aStore in stores) {
NSLog(#"%#", [aStore longName]);
}
}
Which calls this method in my view controller.
StoresViewController.m
#property (strong, nonatomic) NSArray *data;
- (void)didLoadObjects:(NSArray *)aArray
{
NSLog(#"%d", aArray.count);
self.data = [[NSArray alloc] initWithArray:aArray];
NSLog(#"%d", data.count);
[self.tableView reloadData];
}
The values are correct when I ask for the values within this method, but the array shows 0 objects immediately afterwards. Am I missing something here?
I am later checking the value with this method.
- (IBAction)pushMe:(id)sender
{
NSLog(#"Data: %d", self.data.count);
}

You should pass the data in the segue...
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender{
if ([segue.identifier isEqualToString: #"MY_IDENTIFIER"]){
StoresViewController *viewController = segue.destinationViewController;
[viewController didLoadObjects: objects];
}
}
That should work for you! Just change MY_IDENTIFIER to whatever the identifier of your segue is.

StoresViewController is initialised as a local variable which is only accessible in the method that it was declared (aka objectLoader). After objectLoader has completed, the local variable is no longer valid.

The problem is most likely that you're creating multiple instances of StoresViewController instead of giving your network controller a reference to the original instance.
You can demonstrate it to yourself by printing out self in -viewDidLoad and again in didLoadObjects:. You'll see that the pointer addresses are different.
This line is the culprit:
StoresViewController *viewController = [[StoresViewController alloc] init];
Instead of instantiating StoresViewController again, add a property to your SHRetrieveStoresWS class and use it to hold a reference to your view controller.
#property (strong) StoresViewController *viewController;
You'll need to set that property before -didLoadObjects: is invoked.

Related

Using Text Field to add String to NSMutableArray

I am looking to get an NSString value from a Text Field and add it to an array, I want to build an array with many strings in it ex:
[hello, goodbye, too soon].
This is my current solution:
- (IBAction)submitButton:(id)sender {
NSMutableArray *wordArray = [[NSMutableArray alloc] init];
NSString *input = textField.text;
[wordArray insertObject:input atIndex:arrayIndex];
arrayIndex++;
}
This works for the first item in the array, but when I press submit again it reinitializes.My issue is how do I initialize the NSMutableArray to use in the button function, without having it in there so that it doesn't initialize every time. Thank you
Your are using a local array that disappears as soon as the submitButton method is finished.
Make your wordArray an instance variable and initialize it once in viewDidLoad. Then in your submitButton: method (and any others), you reference the instance variable instead of creating local arrays.
Honey's answer is almost, but not, correct.
Your code uses a local variable in your submitButton method, and creates a new, empty array each time the method gets called. Both of those things are wrong.
Honey's answer has you create a different local variable in viewDidLoad. That's also wrong.
You need to make wordArray an instance variable or property of your class. If you class is called ViewController, say, it might look like this
#interface ViewController: UIViewController;
#property (nonatomic, strong) NSMutableArray *wordArray
...
#end
And then initialize it in viewDidLoad:
- (void)viewDidLoad {
[super viewDidLoad];
self.wordArray = [[NSMutableArray alloc] init];
}
Then in the rest of your program refer to self.wordArray, the property.
Here's the solution,
#implementation ViewController{
NSMutableArray *_wordArray;
}
- (void)viewDidLoad {
[super viewDidLoad];
_wordArray = [[NSMutableArray alloc] init];
}
- (IBAction)submitButton:(id)sender {
NSString *input = textField.text;
[wordArray addObject:input];
}
You was re init the array each time you make the action, which will let you always save the last value of the textfield.
but this creates an array as global variable so that you can add all the values entered in textfield.
Hope this help you :)

How to store value in NSMutableArray from ViewControllers

I'm tying to solve my problem which is, i don't know how to store value from (for ex) 4 viewControllers and keep it in the last one. It should be like the scorecard, in first quarter I earned 4pt (and write it in TextField), in second quarter 5pt etc. In the last one it should be summed and sorted etc.
i stared from the last ViewController called it Result, another four called first, second etc.
In Result i created
#property(strong, nonatomic) NSMutableArray *array;
first, second etc inherits array from result and for First I created:
-(void) prepereForSegue:(UIStoryboardSegue*)segue sender :(id)sender
{
if ([segue.identifier isEqualToString:#"id1"]) {
NSString *str1 = [_firstResult text];
Result *Result1 = [segue destinationViewController];
Result1.array = [[NSMutableArray alloc]init];
[Result1.array addObject:str1];
}
}
for second:
-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if([segue.identifier isEqualToString:#"id2"]) {
NSString *str2 = [_SecondResult text];
Result *Result1 = [segue destinationViewController];
Result1.array = [[NSMutableArray alloc]init];
[Result1.array addObject:str2];
}
}
When I run the project in array is just the last score from fourth quarter.
I think that i shouldn't alloc and init NSMutableArray in each viewController but i don't know how make it work..
Please Help me.
Appreciate!
Yup, you are, every time creating a new array which have its current and single object.
Create a shared object and call that array to save and fetch values.
Or just create a array in appdelegate.
Each time you are creating a new array that's why array contains only last value. create an array in appDelegate or use shared object to save the results.

Adding to a NSMutableArray

I can't find an obvious answer this. I'm trying to add things to an array, so I assume I need to use an NSMutableArray
I have a ViewController (CVDownload) and and a TableViewController(CVTableViewController). The NSMutableArray is declared in CVTableViewController.h
#property (strong, nonatomic) NSMutableArray *cvFiles;
I then try to add a string to it in the CVDownload.m
-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
CVTableViewController *controller = (CVTableViewController *)segue.destinationViewController;
[controller.cvFiles addObject:(#"sdsd")];
}
That doesn't work. I'm assuming because I haven't initialised the array. I've tried initialising the array in CVDownload.m
NSMutableArray *cvFiles = [NSMutableArray array];
but that doesn't work either. In debug, the array is still nil. I don't understand where I'm going wrong.
Basically, my goal is to have an array in CVTableViewController that is used to populate a Table, and I want to be able to add to the array in CVDownload. Is there something I'm missing? Does NSArray have a similar method to NSString's stringByAppendingString?
In the init method of CVTableViewController write this:
self.cvFiles = [NSMutableArray new];
CVTableViewController *controller = (CVTableViewController *)segue.destinationViewController;
if(nil == controller.cvFiles)
{
controller.cvFiles = [[NSMutableArray alloc] init];
}
[controller.cvFiles addObject:(#"sdsd")];
Where are you initializing the array? Are you sure that it is created before prepareForSegue: is called?
// Edit: I ask because, as confirmed in the comments, the array is initialized after prepareForSegue: is called. The fix, as mentioned there, is to initialize the array in -awakeFromNib instead of -viewDidLoad.

Passing a MutableArray between ViewControllers

BookingDocumentsViewController *bdVc = [self.storyboard instantiateViewControllerWithIdentifier:#"BookingDocs"];
bdVc.orId = rl_id;
bdVc.docsArray = self.documentsArray;
[self.navigationController pushViewController:bdVc animated:YES];
I have Above code snippet. I'm trying to load a new viewcontroller and assign its Mutable Array (docsArray) object to current view's mutableArray (documentsArray <=this is not nil)
Whenever I execute above code I get EXC_BAD_ACCESS error.
but if I comment the 3rd line. It works but I can't get my array to the new view. I even tried with [[NSMutableArray alloc] initWithArray:self.documentsArray]; this doesnt work either.
But if I use bdVc.docsArray =[[[NSMutableArray alloc] init]; it works but again I can't get my mutable array to the new view.
Edit:
However 2nd line has NSString values. And they can be passed without a problem.
What am I doing wrong here?
I'm not getting any errors in console, instead I get this.
Maybe consider using a Segue. It instantiates the destination viewcontroller for you. Then in your source view controller implement
- (void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
Get a reference to your destination viewcontroller and set its data.
BookingDocumentsViewController *bdVc = [segue destinationViewController];
bdVc.docsArray = self.documentsArray;
in BookingDocumentsViewController.h
#property(nonatomic, retain)NSmutableArray *docsArray;
You do can do in your BookingDocumentsViewController.m:
#synthesize docsArray;
- (void)viewDidLoad
{
NSmutableArray *array = [NSmutableArray alloc]initWithArray:docsArray];
[super viewDidLoad];
}
then when you are pushing the view
BookingDocumentsViewController *bdVc = [self.storyboard instantiateViewControllerWithIdentifier:#"BookingDocs"];
bdVc.orId = rl_id;
bdVc.docsArray = self.documentsArray;
[self.navigationController pushViewController:bdVc animated:YES];
[bdVc Release];
I think I found the issue. A very basic mistake. In bdVc's viewDidLoad I had the following line,
NSLog(#"Booking Documents viewDidLoad : %#",self.docsArray.count);
This was causing the error. that %# instead of %d. I wonder why xcode didn't show proper reason for the error.
Thank you all for the help. :)

Detail View filled with plist information

I've been following a tutorial on iOS development - specifically drill-down UITableViews. I have my own custom plist established, but I can't seem to get the DetailViewController to populate with my plist information. I could really use some help here, I'm a bit over my head!
edit: Here's some details...
The app works through a plist-populated RootViewController, which is a UITableView. When there aren't any children left in the plist, it changes to a Detail view:
AppDelegate.m
NSDictionary *tempDict = [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:#"Data" ofType:#"plist"]];
self.data = tempDict;
RootViewController.m
- (void)viewDidLoad
{
[super viewDidLoad];
if(CurrentLevel == 0) { // At the 'root' of the plist
//Initilalize our table data source
NSArray *tempArray = [[NSArray alloc] init];
self.tableDataSource = tempArray;
AppDelegate *AppDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
self.tableDataSource = [AppDelegate.data objectForKey:#"Rows"];
self.navigationItem.title = #"PedalTome";
}
else
self.navigationItem.title = CurrentTitle;
}
later on...
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
//Get the dictionary of the selected data source.
NSDictionary *dictionary = [self.tableDataSource objectAtIndex:indexPath.row];
//Get the children of the present item.
NSArray *Children = [dictionary objectForKey:#"Children"];
if([Children count] == 0) {
DetailViewController *dvController = [[DetailViewController alloc] initWithNibName:#"DetailView" bundle:[NSBundle mainBundle]];
[self.navigationController pushViewController:dvController animated:YES];
}
else {
//Prepare to tableview.
RootViewController *rvController = [[RootViewController alloc] initWithNibName:#"RootViewController" bundle:[NSBundle mainBundle]];
//Increment the Current View
rvController.CurrentLevel += 1;
//Set the title;
rvController.CurrentTitle = [dictionary objectForKey:#"Title"];
//Push the new table view on the stack
[self.navigationController pushViewController:rvController animated:YES];
rvController.tableDataSource = Children;
}
}
My DetailViewController.m is empty, with the exception of a placeholder self.navigationController.title.
If I'm understanding correctly, I need to pass information from RootViewController to DetailViewController - the location and implementation of the plist, the index level (is that what it's called) in the plist, and the string inside that index level (under the key Detail).
At this point, any progress is amazing progress. Thanks in advance.
You can pass whatever information you need to your DetailViewController by setting up a synthesized property in your DetailViewController, and then passing your data to it inside your if-block.
For example, in your DetailViewController.h you would have the following (without ARC):
#property (retain, nonatomic) NSDictionary *myAwesomeDictionary;
Or, with ARC enabled:
#property (strong, nonatomic) NSDictionary *myAwesomeDictionary;
Then in DetailViewController.m you would have the following:
#synthesize myAwesomeDictionary;
Then you would change your code block to the following:
if([Children count] == 0) {
DetailViewController *dvController = [[DetailViewController alloc] initWithNibName:#"DetailView" bundle:[NSBundle mainBundle]];
[dvController setMyAwesomeDictionary:dictionary];
[self.navigationController pushViewController:dvController animated:YES];
}
This assumes that the NSDictionary called dictionary that you created a few lines above is the data that you'd like to show in your DetailViewController.
Then in your DetailViewController's viewDidLoad: method you can access that dictionary using self.myAwesomeDictionary and do whatever you need to do with it.
Disclaimer:
Two things seem to go against Apple's code style standards in your code:
Your AppDelegate stores your model (your plist). - Apple says that you shouldn't crowd your AppDelegate with global data/logic. In general, only write code that pertains specifically to a class, in that specific class.
You aren't parsing your plist into custom objects. - This makes it hard to code because you constantly have to figure out what your generic Array and Dictionary objects represent, and make your code totally unreadable for other people.
Some of your instance variable names are capitalized. For example, NSArray *Children should be NSArray *children and CurrentLevel should be currentLevel. Only Class names have the first letter capitalized.
Check out http://jlawr3nc3.github.com - specifically my CompanyRecords example code for information on how to make a class and FunWithArrays for how to parse a plist into custom objects. MusicLibraryiOS then delves into how to take a plist, parse it into custom objects, and then display it in a UITableView along with a detail view.
Table View Specifier May do what you need.
Specified Table View is an iOS table view that has its contents specified
via a plist file. Its purpose is largely demonstrative but is also designed
to be used in a live product (useful for credits pages). Can be used with
iOS version 4.2 and above.
A dig through their code will most likely be enlightening.

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