I have a class that retrieves data from core data and stores it into a NSMutablearray. It also has a function that returns this array.
datamanager.h:
#interface DataManager : NSObject {
NSMutableArray *feedItems;
...
}
#property (nonatomic, retain) NSMutableArray *feedItems;
...
datamanager.m:
...
-(void)loadNews{
(load data from core data and put it in self.feedItems)
....
}
-(NSMutableArray*)getAllItems{
return self.feedItems;
}
Now i Have a UIViewController with 2 UIviews (View1 and View2) as IBOutlets. When a button in View1 is clicked it fetches the data from the datamanager class sets it as a NSMutablearray for use for a UItableviewController (tableView1).
After allocating and initializing tableView1 and setting up the Nsmutablearray to populate the table, I add its view as subview to View 2. Now my problem is when I release tableview1 after this procedure I get a EXEC_BAD_ACCESS.
View1 Button IBAction code:
-(void)loadItems{
if ([[dataManager getAllNews] count] > 0) {
ItemTableViewController *tableView1 = [[ItemTableViewController alloc] initWithNibName:#"ItemTableViewController" bundle:nil];
[tableView1 setItemList:[sectionManager getAllItems]];
for (UIView *view in View2.subviews) {
[view removeFromSuperview];
}
[View2 addSubview:tableView1.view];
[tableView1 release]; // if this is not released it works properly else EXEC_BAD_ACCESS
}
}
tableView1 setItemList function:
-(void)setItemList:(NSMutableArray *)list{
self.ItemList = list; //self.ItemList is a NSMutableArray
}
How do I properly release tableView1? Ive tried autorelease too, still doesn't work.
If you are using UIViewController this way, you have to keep your tableView1 retained and then release it later when it is not used anymore. This could be done by placing
[tableView1.view removeFromSuperview];
[tableView1 release];
in your dealloc.
There is a difference between the UITableView and the UITableViewController. The controller should stick around as long as the view is used, so you shouldn't release the UITableViewController (tableView1) there.
Release it in the dealloc method for example.
Also, why do you have a -(NSMutableArray*)getAllItems method? This is an unnecessary step, as a synthesized property already generates getters and setters.
UITableViewControllers are designed to be used with UINavigationControllers and/or UITabBarControllers. They are not meant to be used the way you're doing this.
You CAN make this work, but you're really fighting the OS.
You should either switch to a UINavigationControllers setup, or just use a straight UITableView (without going through a UITableViewController).
Related
My problem is that in ProductNote class UIButton Action I did initWithNibName Notes Class to show the popOver with a UITableView in Notes Class. I am fetching data from sqlite and then load it to UITableView in tableViewDidSelectRowAtindexPath:. I got the selectedNote and creates object of ProductNote Class to call selectedNote instance method that only set IBOutlet's textview.text but its nil. Thats my problem, Below is the code please help me to knowing why i face this type of issue. I am using Xcode 4.3.3 and not using ARC. Manually I defined dealloc method on every ViewController
//**ProductNote.h Class****************************
#import <UIKit/UIKit.h>
#class Notes;
#interface ProductNote : UIViewController<UIPopoverControllerDelegate>
{
UIPopoverController *popOverController;
UITextView *txtmesssagenotes;
Notes *objNotes;
}
#property (retain, nonatomic) IBOutlet UITextView *txtmesssagenotes; //It is Connected to ProductNote.xib
#property (retain,nonatomic) UIPopoverController *popOverController;
#property (retain,nonatomic) Notes *objNotes;
-(IBAction)presentPopOver:(UIButton*)sender;
-(void)selectedNote:(NSString*)note;
#end
//ProductNote.m Class
#implementation ProductNote
#synthesize txtmesssagenotes,popOverController,objNotes;
-(IBAction)presentPopOver:(UIButton*)sender
{
self.objNotes=[[Notes alloc]initWithNibName:#"Notes"bundle:nil];
UIPopoverController *popOver=[[[UIPopoverController alloc]initWithContentViewController:objNotes]autorelease];
self.popOverController=popOver;
self.popOverController.delegate=self;
self.popOverController.popoverContentSize=objNotes.view.frame.size;
CGRect rect=[self.view convertRect:objNotes.view.frame fromView:self.view];
rect.origin.y+=110;
rect.origin.x+=23;
[self.popOverController presentPopoverFromRect:rect inView:self.view permittedArrowDirections:0 animated:YES];
//Then I get popOver with tableview
}
-(void)selectedNote:(NSString*)note
{
self.txtmesssagenotes.text=note;
//Here I am getting txtmesssagenotes=0X0 or nil. Using self or without self Please tell me the reason.
}
- (void)dealloc {
[txtmesssagenotes release];
[popOverController release];
[objNotes release];
[super dealloc];
}
#end
#interface Notes : UITableViewController
{
NSMutableArray *arrNotes;
NSString *selectedNote;
UITableView *tblNotes;
}
#property(nonatomic,retain)NSMutableArray *arrNotes;
#property(nonatomic,retain)NSString *selectedNote;
#property(nonatomic,retain)IBOutlet UITableView *tblNotes;
#end
//Actually I skip the other methods that makes larger program to read . other methods only used to fetch data from sqlite and fill up the arrNotes that is used to fill all rows in the tableview.
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
self.selectedNote=[self.arrNotes objectAtIndex:indexPath.row];
//Here self.arrNotes valid object and contains the data, and assigns NSString object to self.selectedNote
ProductNote *productNote=[[ProductNote alloc]init];
[productNote selectedNote:self.selectedNote]; //after calling selectedNote i goto to selectedNote implementation or definition above.
[productNote release];
}
-(void)dealloc
{
[arrNotes release];
[selectedNote release];
[tblNotes release];
[super dealloc];
}
It is because just as you stated that txtmesssagenotes was created using IB. And you never presented your ProductNote UIViewController instant productNote. So the txtmesssagenotes was never allocated and initialized properly.
Are you calling selectedNote: before your view has loaded?
Just because you created a view controller with a xib doesn't mean that it loads all your subviews immediately.
The xib is parsed and all your views are created the first time that the view controller's view property is asked for - this is usually just before it appears for the first time.
Until then, all the IBOutlet connections will be nil.
You need to store the text for your note as an NSString property of you view controller. Then, inside either viewDidLoad you need to call self.txtmesssagenotes.text=self.note; - viewDidLoad is automatically called just after your view is loaded so you are guaranteed to have all your IBOutlets set by then.
You shouldn't rely on your view objects to store the state of your app (in this case, the text of the note). If a low memory warning is received while your view controller isn't visible then all your view objects will be deleted - they will only be recreated when your view controller becomes visible again - if you are storing your note string inside a UITextView then it might no be there the next time you ask for it :) You should always store data in a property of your view controller (or somewhere else you control) and create your views using it.
im new to IOS and Objective-C and the whole MVC paradigm and i'm stuck with the following.
I am working on (replica) Contact app, also available in iphone as build in app. i want to pass data through another view controller and the data is pass (null) :(.
My Question is, How do I transfer the data from one view to another?
As most the answers you got, passing data between one controller and another just means to assign a variable from one controller to the other one.
If you have one controller to list your contacts and another one to show a contact details and the flow is starting from the list and going to detail after selecting a contact, you may assign the contact variable (may be an object from the array that is displayed in your list) and assign it to the detail view controller just before showing this one.
- (void)goToDetailViewControllerForContact:(Contact *)c
{
ContactDetailViewController *detailVC = [[[ContactDetailViewController alloc] init] autorelease];
detailVC.contact = c;
[self.navigationController pushViewController:c animated:YES];
//[self presentModalViewController:detailVC animated:YES]; //in case you don't have a navigation controller
}
On the other hand, if you want to insert a new contact from the detail controller to the list controller, I guess the best approach would be to assign the list controller as a delegate to the detail one, so when a contact is added the delegate is notified and act as expected (insert the contact to the array and reload the table view?).
#protocol ContactDelegate <NSObject>
- (void)contactWasCreated:(Contact *)c;
// - (void)contactWasDeleted:(Contact *)c; //may be useful too...
#end
#interface ContactListViewController : UIViewController <ContactDelegate>
#property (nonatomic, retain) NSArray *contacts;
...
#end
#implementation ContactListViewController
#synthesize contacts;
...
- (void)goToDetailViewControllerForContact:(Contact *)c
{
ContactDetailViewController *detailVC = [[[ContactDetailViewController alloc] init] autorelease];
detailVC.contact = c;
detailVC.delegate = self;
[self.navigationController pushViewController:c animated:YES];
//[self presentModalViewController:detailVC animated:YES]; //in case you don't have a navigation controller
}
- (void)contactWasCreated:(Contact *)c
{
self.contacts = [self.contacts arrayByAddingObject:c]; //I'm not sure this is the correct method signature...
[self reloadContacts]; //may be [self.tableView reloadData];
}
...
#end
#interface ContactDetailViewController : UIViewController
#property (nonatomic, assign) id<ContactDelegate> delegate;
...
#end
#implementation ContactDetailViewController
#synthesize delegate; //remember to don't release it on dealloc as it is an assigned property
...
- (void)createContactAction
{
Contact *c = [[[Contact alloc] init] autorelease];
[c configure];
[self.delegate contactWasCreated:c];
}
...
#end
Technically, you shouldn't!
The whole idea is not for "views" to control what happens to the data.
What you want to do is to pass data between controllers (which I imagine is exactly what you are planning to do anyway).
You can have shared model (an instance of an object that both view controllers would access) keeping the data you want to share,
You can use notifications to pass data (it is best suited for certain cases).
You can write something to disk and read it again later.
You can use NSUserDefaults.
You can use KeyChain.
...
The best way is:
declare the appropriate #property in the second view controller
when you create it, simply set the property with
viewController.property = valueYouWantToPass;
I'm a big fan of delegates and protocols.
And in some occasions use a Singleton pattern.
two ways to pass/share data between view controller
create an object and sent the data like this
QGraduteYr *tableverify=[[QGraduteYr alloc]initWithStyle:UITableViewStyleGrouped];
tableverify.mystring=myString
[self.navigationController pushViewController:tableverify animated:YES];
another method is stor it in the delegates and use it via shared delegates
MedicalAppDelegate *appdelegate=(MedicalAppDelegate *)[[UIApplication sharedApplication]delegate];
appdelegate.collnameStr=collStr;
and ust this appdelegates value whereever you need
I've got an array populating a small tableView in a DetailView class, and when the user presses a button I need the array to be sent to another View Controller, to populate a tableView there, but I'm having some difficulty getting it working. This is what I've been trying to do so far:
*DetailViewController.m*
#import "DetailViewController.h"
#import "OtherViewController.h"
-(IBAction) toCart:(id)sender {
OtherViewController *oVC = [[OtherViewController alloc] init];
oVC.shoppingList = sList;
NSLog(#"Ingredients count %d", [sList count]); //This returns a number, so the sList definitely contains values, and the method is definitely being called.
[oVC release];
}
*OtherViewController.m*
#import "OtherViewController.h"
#import "DetailViewController.h"
#synthesize shoppingList;
-(void) viewWillAppear: (BOOL)animated {
NSLog(#"list count: %d", [shoppingList count]); // This returns 0
}
sList is populated elsewhere in the class, and sList and shoppingList are both declared in their respective .h files, with #property (nonatomic, retain)...
Any help much appreciated!
As you are having taBbarcontroller, so you can proceed as follows :
Create references of your you viewControllers(which are associated with tabbar as topViewController) in your appDelegate.
otherViewController = [[tabBarController.viewControllers objectAtIndex:<tabIndex>] topViewController];
make it as #property in appDelegate so that you can access it anywhere in your app.
now,
-(IBAction) toCart:(id)sender {
//appDelegate <--- get reference to your application delegate using [[UIApplication sharedApplicaiton]delegate] do not forget to properly type cast it.
OtherViewController *oVC = [appDelegate otherViewController];
oVC.shoppingList = sList;
NSLog(#"Ingredients count %d", [sList count]);
//This returns a number, so the sList definitely contains values, and the method is definitely being called.
// [oVC release]; no need to release it...
}
//also make sure you do not initialize shoppingList of otherViewController in viewDidLoad(or any other method) of otherViewController, else it will be overwritten(lost its previous reference).
in your appDelegate's .h write
#property OtherViewController *otherViewController;
in appDelegate's.m
#synthesize otherViewController;
in appDelegates's .m (method didFinishLaunchingWithOptions: ) write
otherViewController = [[tabBarController.viewControllers objectAtIndex:<tabIndex>] topViewController];
Thanks
In toCart:, you are creating an OtherViewController and then immediately throwing it away. Whatever OtherViewController is calling -viewWillAppear, it isn't the one you're creating in toCart:. How is that object created and put on the screen? You need a pointer to it to modify it.
Better, though, would be to move your model data out of the view controllers and put it in a single ShoppingCart object. Then all your view controllers would have a reference to it (or you can make ShoppingCart a singleton if that makes sense in your program). This way, any time you change the shopping cart from anywhere, all views will correctly update without having to tell every view controller about every other view controller.
I am getting data from NSTextField, and saving data in NSMutableArray. I want to show the same data in another class which in child of UITableViewController.
How can I show data of NSMutableArray to myTableView which is another class??
Help me out, please
Surely, I will appraise if I found proper way.
Your tableView is in a MyViewController class. You need to create a NSMutableArray *sourceArray attribute on that class, as well as the associated property, using for instance:
#property (nonatomic, retain) NSMutableArray *sourceArray;
Then when you instantiate this View Controller or whenever you make it appear, assign the results to sourceArray :
MyViewController *mvc = [[MyViewController alloc] initWith...];
mvc.sourceArray = theResult;
[self presentModalViewController:mvc animated:YES];
[mvc release];
Then use the sourceArray as the Table View datasource.
Make a property of NSMutableArray in app delegate class and assign the result of the source array to it as soon as you fetch any result, because you can access its instance all over your project.
I have an NSMutableArray in my MainViewController classes.. I added 10 Objects to NSMutableArray.When i Click subview button in my MainViewController classes, I push SubviewController (UIViewController)classes.... In subviewcontroller classes i want to use MainViewController Values of NSMutableArray. And also i Want to add or remove objects from that NSMutableArray...
My aim is I want to use the NSMutableArray Values to all UIViewController classes to my project with an same name of the variable.
If I understand you right - you want to access the NSMutableArray in MainViewController from all your (subview) controllers?
You can store the handle to your MainViewController in all you subviews and access the array using that handle.
I think better idea would be move the data to some globally accessible instance (e.g. to ApplicationDelegate class or wrap it into singleton class)
What you want to do is add a Cocoa property in your main view controller that references the NSMutableArray instance which you instantiate and populate with elements.
In the header:
#interface MainViewController : UIViewController {
NSMutableArray *myMutableArray;
}
#property (nonatomic, retain) NSMutableArray *myMutableArray;
#end
In the implementation, add the #synthesize directive and remember to release the array in -dealloc:
#implementation MainViewController
#synthesize myMutableArray;
...
- (void) dealloc {
[myMutableArray release];
[super dealloc];
}
#end
You also want to add this property to view controllers that are subordinate to the main view controller, in the exact same way.
In your main view controller, when you are ready to push the subordinate view controller, you set the subordinate view controller's property accordingly:
- (void) pushSubordinateViewController {
SubordinateViewController *subVC = [[SubordinateViewController alloc] initWithNibName:#"SubordinateViewController" bundle:nil];
subVC.myMutableArray = self.myMutableArray; // this sets the sub view controller's mutable array property
[self.navigationController pushViewController:subVC animated:YES];
[subVC release];
}
Likewise in your subordinate view controller, it will need to set its subordinate's mutable array property accordingly, when it pushes its own view controller.
By setting references in this way, each view controller is pointed at the same mutable array, containing the desired elements.
To use the array, just call self.myMutableArray, e.g. [self.myMutableArray addObject:object].