I am getting error:use of undeclared identifier
here is the code for view controller where I am accessing the object of model class mapMembersData
for (NSMutableDictionary *getMemberElements in arData)
{
mapMembersData *notModelObject = [mapMembersData sharedInstance];//showing error
[notModelObject assignMemberData:getMemberElements];
[memberArray addObject:notModelObject];
}
Here is the code of model class:
#import <CoreLocation/CoreLocation.h>
#import <Google-Maps-iOS-Utils/GMUMarkerClustering.h>
#interface mapMembersData : NSObject<GMUClusterItem>
#property(nonatomic,retain) NSString *chatToken;
#property(nonatomic,retain) NSString *address;
+ (mapMembersData *)sharedInstance;
- (mapMembersData *)assignMemberData:
#end
#import "mapMembersData.h"
#import "Constants.h"
#implementation mapMembersData
#synthesize chatToken,
address,
static mapMembersData *instance;
+(mapMembersData *)sharedInstance{
#synchronized(self)
{
instance = [[super alloc] init];
}
return instance;
}
- (mapMembersData *)assignMemberData:(NSMutableDictionary*)getMemberElements
{
chatToken = [objdelegate checkIfStringIsEmpty:[getMemberElements
objectForKey:#"chatToken"]];
address = [objdelegate checkIfStringIsEmpty:[getMemberElements
objectForKey:#"address"]];
return self;
}
#end
What am I doing wrong?
In your storyboard there must be a controller, in which you had set a class with storyboard id, and you removed that class from that storyboard but the storyboard id is still addressing it, like below image:
So you have to remove that Storyboard ID and uncheck that "Use Story Board ID".
That's all.
After scratching my head for a day. I manage to get ride off the bizarre errors.
Finding starts from below:
1.mapMembersData-class were residing in two different folders of the workspace (In XYZ-folder and one at outside the folder). mapMembersData- the class was referenced by project i.e inside XYZ and other was just placed.
the controller from where I was accessing the mapMembersData, was at outside XYZ-folder, thus creating ambiguity.
I deleted unused referenced classed and confirm controller should access correctly.
Related
I am having difficulty passing variable from one class file to another. I have tried the Global Variable creator extern, but that also doesn't work.
Specifically, I am trying to pass a variable from a new class file I created called NDSClassSiteViewController to the master controller NDSClassMasterViewController.
I have added the #property into the .h file as follows:
#interface NDSClassSiteViewController : UITableViewController {
NSArray *sitesMenu;
}
#property (nonatomic, retain) NSString *siteid;
#end
And then the #synthesize into the .m file as follows:
#import "NDSClassSiteViewController.h"
#import "NDSClassMasterViewController.h"
#interface NDSClassSiteViewController () {
NSMutableArray *_objects;
}
#end
#implementation NDSClassSiteViewController
#synthesize siteid;
I set the variable in the .m file as follows:
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.identifier isEqualToString:#"showMenu"]) {
NSInteger row = [[self tableView].indexPathForSelectedRow row];
//NSArray *appcell = [sitesMenu objectForKey:#"Table"];
NSLog(#"AppCell %#", sitesMenu);
NSDictionary *entry = [sitesMenu objectAtIndex:row];
self.siteid = [entry objectForKey:#"SITEID"];
NSLog(#" sample SiteView %#", siteid);
//NDSClassMasterViewController *detailController = segue.destinationViewController;
//detailController.detailItemTwo = siteid;
}
}
Then I try and access it in the Master View controller using the following:
- (void)viewDidLoad
{
[super viewDidLoad];
globalid = siteid;
}
But I get an error: use of undeclared identifier siteid
I don't really know why it won't allow me to use the variable? Am I missing something?
You've declared a property on NDSClassSiteViewController. To access the property you need an instance of an NDSClassSiteViewController within scope, and you also must access it using the syntax for properties - either dot syntax or standard method call syntax.
To read the property:
aSiteViewController.siteID
[aSiteViewController siteID]
To set it:
aSiteViewController.siteID = #"Site ID here";
[aSiteViewController setSiteID:#"Site ID Here"]
When you are in a method of NDSClassSiteViewController then self points to the instance you likely want to use. Otherwise, you'll probably either create it in the method or have it passed in as a parameter. Also, when you are in an instance method of NDSClassSiteViewController you can access the instance variable that backs the property directly - usually this would be _siteID but you manually synthesized so just siteID should work. Note that I did siteID instead of the siteid you're using. I did this for readability and to follow established Objective-C naming conventions.
I have a singleton that I'd like to use to manage the onscreen animation of my views. Here's my.
#import <Foundation/Foundation.h>
#interface OAI_AnimationManager : NSObject {
NSMutableDictionary* sectionData;
}
#property (nonatomic, retain) NSMutableDictionary* sectionData;
+(OAI_AnimationManager* )sharedAnimationManager;
- (void) checkToggleStatus : (UIView* ) thisSection;
#end
.m file
#import "OAI_AnimationManager.h"
#implementation OAI_AnimationManager
#synthesize sectionData;
+(OAI_AnimationManager *)sharedAnimationManager {
static OAI_AnimationManager* sharedAnimationManager;
#synchronized(self) {
if (!sharedAnimationManager)
sharedAnimationManager = [[OAI_AnimationManager alloc] init];
return sharedAnimationManager;
}
}
- (void) checkToggleStatus : (UIView* ) thisSection {
//get the section data dictionary
NSLog(#"%#", sectionData);
}
#end
You'll see in the .h file I added a NSMutableDictionary and am using #property/#synthesize for it's getter and setter.
In my ViewController I instantiate the animation manager as well as a series of subclasses of UIView called Section. With each one I store the data (x/y w/h, title, etc.) in a dictionary and pass that to the dictionary delcared in animation manager. In the Section class I also instantiate animation manager and add a UITapGestureRecognizer which calls a method, which passes along which section was tapped to a method (checkToggleStatus) in animation manager.
As you can I see in the method I am just logging sectionData. Problem is I am getting null for the value.
Maybe my understanding of singletons is wrong. My assumption was the class would only be instantiated once, if it was already instantiated then that existing object would be returned.
I do need all the other Section classes data as if one animates others animate in response and I can get around it by passing the tapped Section to the animation manager and doing [[Section superview] subviews] and then looping and getting the data from each that way but it seems redundant since that data is available in the ViewController when they are created.
Am I doing something wrong in trying to transfer that data? Is there a better solution? I am open to suggestions and criticisms.
Thanks
h file
#interface OAI_AnimationManager : NSObject
#property (nonatomic, retain) NSMutableDictionary* sectionData;
+(OAI_AnimationManager* )sharedAnimationManager;
- (void) checkToggleStatus : (UIView* ) thisSection;
#end
m file
static OAI_AnimationManager* _sharedAnimationManager;
#implementation OAI_AnimationManager
#synthesize sectionData = _sectionData;
+(OAI_AnimationManager *)sharedAnimationManager {
#synchronized(self) {
if (!_sharedAnimationManager) {
_sharedAnimationManager = [[OAI_AnimationManager alloc] init];
}
}
return _sharedAnimationManager;
}
- (void) checkToggleStatus : (UIView* ) thisSection {
//get the section data dictionary
NSLog(#"%#", _sectionData);
}
#end
Notice I moved your sectionData variable from the header and moved it to the implementation file. A while back, they changed it to where you can synthesize properties and specify their instance variable names along side it... hence:
sectionData = _sectionData;
I also added and underscore to the instance variable... this is a universal convention for private variables and it also will throw a compile error now if you try to type just sectionData as you did in the return statement of checkToggleStatus:. Now you either have to type self.sectionData or _sectionData.
You didn't include the code that creates an instance of your dictionary but I bet you didn't set it as self.sectionData = [[NSDictionary alloc] init] which means it would not retain the value and you would get null the next time you called it. Classic memory management mistake... I know it well because I learned the hard way hehehe
this is a follow-up question to my last one here: iOS: Initialise object at start of application for all controllers to use .
I have set my application up as follows (ignore the DB Prefix):
DBFactoryClass // Built a DataManaging Object for later use in the app
DBDataModel // Is created by the factory, holds all data & access methods
DBViewControllerA // Will show some of the data that DBDataModel holds
moreViewControllers that will need access to the same DBDataModel Object
i will go step by step through the application, and then post the problem in the end
AppDelegate.h
#import "DBFactoryClass.h"
AppDelegate.m
- (BOOL)...didFinishLaunching...
{
DBFactoryClass *FACTORY = [[DBFactoryClass alloc ]init ];
return YES;
}
DBFactoryClass.h
#import <Foundation/Foundation.h>
#import "DBDataModel.h"
#interface DBFactoryClass : NSObject
#property (strong) DBDataModel *DATAMODEL;
#end
DBFactoryClass.m
#import "DBFactoryClass.h"
#implementation DBFactoryClass
#synthesize DATAMODEL;
-(id)init{
self = [super init];
[self setDATAMODEL:[[DBDataModel alloc]init ]];
return self;
}
#end
ViewControllerA.h
#import <UIKit/UIKit.h>
#import "DBDataModel.h"
#class DBDataModel;
#interface todayViewController : UIViewController
#property (strong)DBDataModel *DATAMODEL;
#property (weak, nonatomic) IBOutlet UILabel *testLabel;
#end
ViewControllerA.m
#import "todayViewController.h"
#implementation todayViewController
#synthesize testLabel;
#synthesize DATAMODEL;
- (void)viewDidLoad
{
todaySpentLabel.text = [[DATAMODEL test]stringValue]; // read testdata
}
#end
DBDataModel.h
#import <Foundation/Foundation.h>
#interface DBDataModel : NSObject
#property (nonatomic, retain) NSNumber* test;
#end
DBDataModel.m
#import "DBDataModel.h"
#implementation DBDataModel
#synthesize test;
-(id)init{
test = [[NSNumber alloc]initWithInt:4]; // only a testvalue
return self;
}
#end
the app builds fine, and starts up but the label stays blank. so either the object does not exist (but i guess this would result in an error message), or something else is wrong with my setup. any thoughts?
Two notes:
Your have a shotgun approach to asking questions: everytime you hit a stumbling block, you ask a question and if the answer does not work immediately, you ask another one. You have to spend some energy in between the questions debugging and poking into the code on your own, otherwise you will depend on the external help forever.
Use the common coding style please. CAPS are reserved for macros.
Now to the code:
- (BOOL) …didFinishLaunching…
{
DBFactoryClass *factory = [[DBFactoryClass alloc] init];
return YES;
}
This simply creates an instance of the DBFactoryClass and then throws it away. In other words, it’s essentially a no-op. Judging by the comments in the previous answer you create the controllers using the Storyboard feature. How are they supposed to receive the reference to the data model? The reference isn’t going to show up by magic, you have to assign it somewhere.
I’m not familiar with the Storyboard feature. The way I would do it is to create the view controllers using separate XIB files, then you can create the controller instances in the Factory class and pass them the needed reference to the model. In the end the application delegate would create the factory, ask it to assemble the main controller and then set it as the root view controller for the window. Just like in my sample project. It’s possible that there’s a way to make it work with storyboards, but as I said, I am not familiar with them.
I have a Cocoa project with an object that holds information from a SQLite database.
By now the information is stored in memory by this object and is used in the user interface to read and write new information.
But now I came to a small problem... I decided to create a new controller class to handle the actions of an NSTableView and I want to access this same database object that was declared elsewhere.
Which is the best option to access this information? I wish to avoid loading the information more than once in memory and also avoid use pure C/C++ codes with global variables.
It is better to understand my point by looking at the code.
I accept other solutions as well, naturally.
My idea of code is currently like this:
FirstClass.h
#import <Foundation/Foundation.h>
#import "DatabaseModel.h"
#interface FirstClass : NSObject {
IBOutlet NSScrollView *informationListTable;
NSMutableArray *informationList;
}
#end
FirstClass.m
#import "FirstClass.h"
#implementation FirstClass
- (void)awakeFromNib{
DatabaseModel *list = [[DatabaseModel alloc] init];
informationList = [[NSMutableArray alloc] initWithArray:[list loadList]];
[list release];
[machinesListTable reloadData];
}
SecondClass.h
#import <Foundation/Foundation.h>
#interface SecondClass : NSObject {
IBOutlet NSTextField *labelName;
NSString *name;
}
- (IBAction)showName:(id)sender;
#end
SecondClass.m
#import "FirstClass.h"
#import "SecondClass.h"
#implementation SecondClass
- (IBAction)showName:(id)sender{
/*
Here name must get something like:
[[FirstClass.informationList objectAtIndex:3] name]
Here labelName must display name.
*/
}
#end
you can either create the object once then pass the object around, with each controller retaining it as needed. Or you can use a singleton instance. I would say the singleton instance is easier to read, but it depends on the application
One solution would be to make FirstClass a singleton. Then, anywhere else in your code, you could call [FirstClass sharedInstance] (replace sharedInstance with the name you'll give to your class method) and use this object. You'll have to be careful about concurrency issues though.
In a first controller, I create an instance variable for my model, because I want to edit its content from a controller and then access the same object from another controller.
In the second controller, I get an error when trying to access the object:
Property 'levels' not found on object of type FirstController.
Model.h
#imports....
#property (readwrite,copy) NSMutableString *answersString;
FirstController.h
#import <UIKit/UIKit.h>
#import "Model.h"
#interface FirstController : UIViewController{
// some declarations
}
#property (nonatomic, retain) LevelsCompleted *levels;
#end
FirstController.m
#import "FirstController.h"
#interface FirstController(){
//stuff
}
#end
#implementation FirstController
#synthesize levels;
//stuff
- (IBAction)backButton:(id)sender { // This is the changeAnswerString method
if (levels ==nil) self.levels = [[LevelsCompleted alloc]init];
self.levels.answersString=#"1";
[self dismissModalViewControllerAnimated:NO];
}
#end
SecondController.m
#import "SecondController.h"
#import "FirstController.h"
#interface SecondController(){
//stuff
}
#end
#implementation SecondController
-(void) viewWillAppear:(BOOL)animated{
NSLog(#"%#",FirstController.levels.answersString);
// the line above gives me the error "Property 'levels' not found on object of type FirstController
}
#end
Can someone tell me what I am doing wrong here? I have tried to create a FirstController object in the SecondController.h, but this does not give me the same property and hence I do not get the right value of the NSString I modified in the first view.
levels is a instance variable so you cannot access it without instantiating an object first.
You should do something like
FirstController *controller = [[FirstController alloc] initWithNibName:#"First" bundle:nil];
NSLog(#"%#",controller.levels.answersString);
[controller release]
You cannot access another viewcontroller from current viewcontroller directly. Define Level in AppDelagte method and then you can access it from anywhere.
What about moving/adding the LevelsCompleted *levels property to the secondviewcontroller and fill SecondViewcontroller.levels.answerstring when you use backbutton: in you first controller?
As a advice try NSUSERDEFAULT to access it,.,
By Doing Things As Below you can Achive as You want
Ddeclare NSMutableString As in your viewController Class As Global variable.
1) LevelsCompleted.h Class
#import <UIKit/UIKit.h>
NSMutableString *answersString;// In this way this answersString would accessible through out the Application and No Need to make property & synthesiz answersString .
#interface LevelsCompleted : UIViewController{
}
LevelsCompleted.m Class
//First create that NSMutableString object in its LevelsCompleted.m class
#import"LevelsCompleted.h"
#interface LevelsCompleted
-(void)viewDidLoad{
answersString=[NSMutableString alloc]init];//here created answersString object
}
#end //end of LevelsCompleted
2)FirstController.h class
#import <UIKit/UIKit.h>
extern NSMutableString *answersString;
#interface FirstController : UIViewController{
// some declarations
}
#end
FirstController.m class
#import "FirstController.h"
#implementation FirstController
- (IBAction)backButton:(id)sender {
// Because i have created that answersString Global in LevelsCompleted.h class
//we can directly Access and can set the any string Value to that answersString as Below
answersString=#"1";
[self dismissModalViewControllerAnimated:NO];
}
#end
SecondController.h class
extern NSMutableString *answersString;// please do this carefully fro getting access the answersString instance
#interface SecondController:UIViewController{
//stuff
}
#end
SecondController.m class
#implementation SecondController
-(void) viewWillAppear:(BOOL)animated{
NSLog(#"%#",answersString);//here you may access easily.
}
#end
In above code everything would work because i have done the same thing in my app
just try to catch the concept of extern, global variable .