I know theres a better solution using arc4random (it's on my to-try-out-function list), but I wanted to try out using the rand() and stand(time(NULL)) function first. I've created a NSMutableArray and chuck it with 5 data. Testing out how many number it has was fine. But when I tried to use the button function to load the object it return me with object <sampleData: 0x9a2f0e0>
- (IBAction)generateNumber:(id)sender {
srand(time(NULL));
NSInteger number =rand()% ds.count ;
label.text = [NSString stringWithFormat:#"object %#", [ds objectAtIndex:number] ];
NSLog(#"%#",label.text);
}
While I feel the main cause is the method itself, I've paste the rest of the code below just incase i made any error somewhere.
ViewController.h
#import <UIKit/UIKit.h>
#import "sampleData.h"
#import "sampleDataDAO.h"
#interface ViewController : UIViewController
#property (weak, nonatomic) IBOutlet UILabel *label;
#property (weak, nonatomic) IBOutlet UIButton *onHitMePressed;
- (IBAction)generateNumber:(id)sender;
#property(nonatomic, strong) sampleDataDAO *daoDS;
#property(nonatomic, strong) NSMutableArray *ds;
#end
ViewController.m
#import "ViewController.h"
#interface ViewController ()
#end
#implementation ViewController
#synthesize label;
#synthesize onHitMePressed;
#synthesize daoDS,ds;
- (void)viewDidLoad
{
[super viewDidLoad];
daoDS = [[sampleDataDAO alloc] init];
self.ds = daoDS.PopulateDataSource;
// Do any additional setup after loading the view, typically from a nib.
}
- (void)viewDidUnload
{
[self setLabel:nil];
[self setOnHitMePressed:nil];
[super viewDidUnload];
// Release any retained subviews of the main view.
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation != UIInterfaceOrientationPortraitUpsideDown);
}
- (IBAction)generateNumber:(id)sender {
srand(time(NULL));
NSInteger number =rand()% ds.count ;
label.text = [NSString stringWithFormat:#"object %#", [ds objectAtIndex:number] ];
NSLog(#"%#",label.text);
}
#end
sampleData.h
#import <Foundation/Foundation.h>
#interface sampleData : NSObject
#property (strong,nonatomic) NSString * object;
#end
sampleData.m
#import "sampleData.h"
#implementation sampleData
#synthesize object;
#end
sampleDataDAO.h
#import <Foundation/Foundation.h>
#import "sampleData.h"
#interface sampleDataDAO : NSObject
#property(strong,nonatomic)NSMutableArray*someDataArray;
-(NSMutableArray *)PopulateDataSource;
#end
sampleDataDAO.m
#import "sampleDataDAO.h"
#implementation sampleDataDAO
#synthesize someDataArray;
-(NSMutableArray *)PopulateDataSource
{
someDataArray = [[NSMutableArray alloc]init];
sampleData * myData = [[sampleData alloc]init];
myData.object= #"object 1";
[someDataArray addObject:myData];
myData=nil;
myData = [[sampleData alloc] init];
myData.object= #"object 2";
[someDataArray addObject:myData];
myData=nil;
myData = [[sampleData alloc] init];
myData.object= #"object 3";
[someDataArray addObject:myData];
myData=nil;
myData = [[sampleData alloc] init];
myData.object= #"object 4";
[someDataArray addObject:myData];
myData=nil;
myData = [[sampleData alloc] init];
myData.object= #"object 5";
[someDataArray addObject:myData];
myData=nil;
return someDataArray;
}
#end
what i guess is going on is that nslog function cant print the data inside your sample data class because its not a standard class. not standard classes must implement the "description" method. What you get when you print out your class is the pointer to it, because nslog has no way of knowing how to print out the data in your class.
if what you want to print on that label/nslog is the nsstring inside your class "sampledata" you should access the property.
this can be done in the following way:
SampleData *instanceOfSampleData = (SampleData*)[ds objectAtIndex:number];
label.text = [NSString stringWithFormat:#"object %#", instanceOfSampleData.object];
Related
I am new to Objective C, I'm trying to add objects to NSMutableArray that I can use multiple times on my project. I have a Model class as
History.h
import
#interface History : NSObject
#property (nonatomic) NSString *itemName;
#property (nonatomic) int quantity;
#property (nonatomic) double total;
#property (nonatomic) NSDate *purchaseDate;
- (instancetype)initWithName: (NSString*)itemName withQuantity:(int)quantity withTotal:(double) total withPurchaseDate:(NSDate*) purchaseDate;
#end
History.m
#import "History.h"
#implementation History
-(instancetype)initWithName: (NSString*)iName withQuantity:(int)iQuantity withTotal:(double) iTotal withPurchaseDate:(NSDate*) iPdate {
self = [super init];
if(self) {
self.itemName = iName;
self.quantity = iQuantity;
self.quantity = iQuantity;
self.purchaseDate = iPdate;
}
return self;
}
#end
Repository.h
#import <Foundation/Foundation.h>
#interface Repository : NSObject
#property (nonatomic) NSMutableArray *itemHistory;
-(void) pushToArray:(NSString *)name withQuantity:(int)qty withTotal:(double) total withPurchaseDate:(NSDate*) pDate;
#end
Repository.m
#import "Repository.h"
#import "History.h"
#interface Repository()
//#property (nonatomic) NSMutableArray *itemHistory;
#end
#implementation Repository
-(NSMutableArray *) itemHistory {
if(_itemHistory == nil) {
_itemHistory = [[NSMutableArray alloc] init];
}
return _itemHistory;
}
This is my method that I want to use to add objects to the MutableArray.
-(void) pushToArray:(NSString *)name withQuantity:(int)qty withTotal:(double) total withPurchaseDate:(NSDate*) pDate {
self.itemHistory = [[NSMutableArray alloc] init];
History *obj = [[History alloc] init];
obj.itemName = name;
obj.quantity = qty;
obj.total = total;
obj.purchaseDate = pDate;
[self.itemHistory addObject:obj];
}
#end
Thank you for your help in advance.
Every time you call pushToArray:... you are replacing the existing itemHistory with a new, empty, mutable array. You'll only ever see the last item to be pushed in that array.
However, you also don't need to lazily initialize _itemHistory. Just create an instance in your init method and be done with it. Saves confusion and refactoring hell.
In your Repository class, simply implement the designated initializer:
- (instancetype) init
{
if (self=[super init]) {
_itemHistory = [[NSMutableArray alloc] init];
}
return self;
}
Uncomment the property:
#interface Repository()
#property (nonatomic) NSMutableArray *itemHistory;
#end
And remove this from the -pushToArry:... method:
//self.itemHistory = [[NSMutableArray alloc] init];
If it still doesn't work, you need to show how you are logging the failure.
I have quick question regarding my code:
This is my Animal.h header file:
#import <Foundation/Foundation.h>
#interface Animal : NSObject
#property (nonatomic) int age;
#property (nonatomic, strong) NSString *name;
#property (nonatomic,strong) NSString *breed;
#property (retain, nonatomic) UIImage *image;
-(void) bark;
-(void)barkNumTimes: (int)numOfTimesToBark;
-(void)barknumTimes:(int)numberOfTimes loudly:(bool) isLoud;
-(int) ageInDogYears: (int)humanYears;
#end
For some reason at the line:
#property (retain, nonatomic) UIImage *image;
I get an error saying that "Property with 'retain (or strong)' attribute must be of object type".
My ViewController.m class is where I created three Animal objects and used the UIImage property which I created in Animal.h and set each of the Animal objects UIImage property to a certain image I have in my supporting files:
#import "ViewController.h"
#import "Animal.h"
#import "Puppy.h"
#interface ViewController ()
#end
#implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
self.whichDog = 0;
Animal *whiteDog = [[Animal alloc]init];
[whiteDog setName:#"white"];
[whiteDog setBreed:#"White Dog"];
whiteDog.image = [UIImage imageNamed:#"whitedog.jpeg"];
Animal *brownDog = [[Animal alloc] init];
[brownDog setName:#"brown"];
[brownDog setBreed:#"Brown Dog"];
brownDog.image = [UIImage imageNamed:#"browndog.jpeg"];
Animal *husky = [[Animal alloc] init];
[husky setName:#"husky"];
[husky setBreed:#"Husky Dog"];
husky.image = [UIImage imageNamed:#"husky.jpeg"];
self.myAnimals = [[NSMutableArray alloc] init];
[self.myAnimals addObject:whiteDog];
[self.myAnimals addObject:brownDog];
[self.myAnimals addObject:husky];
Puppy *pup = [[Puppy alloc]init];
[pup setName:#"coby"];
[pup setBreed:#"Portuguese Water Dog"];
pup.image = [UIImage imageNamed:#"puppy.jpeg"];
}
- (IBAction)newDogBarButton:(UIBarButtonItem *)sender{
int numOfDogs = (int)[self.myAnimals count];
int randomIndex = arc4random() % numOfDogs;
Animal *randomAnimal = [self.myAnimals objectAtIndex:randomIndex];
[UIView transitionWithView:self.view duration:1.5 options:UIViewAnimationOptionTransitionCurlDown animations:^{
self.imageView.image = randomAnimal.image;
self.carNAme.text = randomAnimal.name;
self.extra.text = [randomAnimal breed];
} completion:^(BOOL finished) {
}];
sender.title = #"And Another";
self.whichDog = randomIndex;
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
#end
For some reason in Animal.h I keep getting that error which says "Property with 'retain (or strong)' attribute must be of object type". I am not very sure on what this retain or strong means in the properties, but can someone please explain to me what I am doing wrong in my code. Thank you so much for the help.
UIImage belongs to UIKit, so import UIKit instead of Foundation
So I'm creating an array called fruits which I would like to share between multiple views. This is my code:
#import <foundation/Foundation.h>
#interface MyManager : NSObject {
NSMutableArray *fruits;
}
#property (nonatomic, retain) NSMutableArray *fruits;
+ (id)sharedManager;
#end
#import "MyManager.h"
static MyManager *sharedMyManager = nil;
#implementation MyManager
#synthesize fruits;
#pragma mark Singleton Methods
+ (id)sharedManager {
#synchronized(self) {
if (sharedMyManager == nil)
sharedMyManager = [[self alloc] init];
}
return sharedMyManager;
}
- (id)init {
if ((self = [super init])) {
fruits = [[NSMutableArray alloc] init];
}
return self;
}
-(void) dealloc{
self.fruits = nil;
[super dealloc];
}
#end
Now I'm using the following code so that I can use workouts in the new view
#import "MyManager.h"
#interface Chest : UIViewController {
IBOutlet MyManager *fruits;
}
#property (nonatomic, retain) IBOutlet MyManager *fruits;
-(IBAction) goToList: (id) sender;
#end
When a button is clicked, goToList is called, and I populate my array, fruits
#import "Chest.h"
#implementation Chest
#synthesize fruits;
-(IBAction) goToList:(id)sender{
MyManager *fruits = [MyManager sharedManager];
NSString *filePath;
NSString *fileContents;
filePath = [[NSBundle mainBundle] pathForResource:#"chest_strength" ofType:#"csv"];
fileContents = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:nil];
fruits = [fileContents componentsSeparatedByString:#"\n"];
}
When I output the elements of *fruits in this view, everything works fine. Now when I try to access this same variable in the other view, it says the array is null. Here's the code for the second view:
#interface List : UIViewController {
IBOutlet MyManager *fruits;
}
#property (nonatomic, retain) IBOutlet MyManager *fruits;
#end
#import "List.h"
#import "MyManager.h"
#implementation List
#synthesize fruits
NSLog(#"%#", fruits); //This is the part that isn't displaying correctly. I'm getting a null here
So my question is, how do I do this so that I can get the array fruits that I populated in Chest and use it in List so that I can display the contents of the array in that view?
Thank you to everybody who answers. This problem is seriously bogging me down and I need to finish this project ASAP. Much appreciated.
You've changed a few things in this question but the fundamental problem remains: the array is a property of your singleton, and you are not treating it as such.
Whenever you refer to the array, outside of the singleton, do it like this:
[MyManager sharedManager].fruits
If you are accessing it frequently, you can create a local ivar, but you certainly wouldn't have it as an IBOutlet, which you are doing in your last code sample. How is that ever going to be set?
I have a small piece of code that sets the NSString (strUsername) of the class Username to the value which is typed into a UITextField and then a button is pressed. This works fine:
UsernameViewController.m
#import <UIKit/UIKit.h>
#import "Username.h"
#interface UsernameViewController : UIViewController
{
Username *username;
__weak IBOutlet UITextField *test;
}
#property (nonatomic, retain)IBOutlet UITextField *txtUsername;
#property (nonatomic, retain) IBOutlet UITextField *test;
-(IBAction)setUsername;
#end
#import "UsernameViewController.h"
#import "Username.h"
#implementation UsernameViewController
#synthesize test=_test;
- (void)viewDidLoad
{
[super viewDidLoad];
username = [[Username alloc] init];
}
-(IBAction)setUsername
{
NSString *inputUsername = self.test.text;
NSLog(#"inputUsername is: %#", inputUsername);
username.strUsername = inputUsername;
NSLog(#"the username.strUsername is now: %#", username.strUsername);
}
My NSLog output shows that the UItextfield input and NSString setter are working:
LocNews1[6699:707] inputUsername is: Harry brown
LocNews1[6699:707] the username.strUsername is now: Harry brown
Now when it hit the back button on this view it return me back to a UITableViewController. I then perform a pull down to refresh action and its called the following method:
TestViewController.m (UITableViewController type)
#import "TestViewController.h"
#import "ViewController.h"
#import "DetailViewController.h"
#import "AppDelegate.h"
#import "NewsArticle.h"
#import "ResultsCustomCell.h"
#import "XMLParser.h"
#implementation TestViewController
//some code
- (void)addItem
{
username = [[Username alloc] init];
// Use XMLparser to check for updated new feeds.
if(username.strUsername != NULL)
{
NSLog(#"ViewController username.strUsername is:%#",username.strUsername);
activeUsername = username.strUsername;
}
else
{
NSLog(#"%#",username.strUsername);
activeUsername = #"";
}
NSString *myLat = [[NSString alloc] initWithFormat:#"%f", locationManager.location.coordinate.latitude];
NSString *mylong = [[NSString alloc] initWithFormat:#"%f", locationManager.location.coordinate.longitude];
XMLParser *parseQuestionnaire = [[XMLParser alloc] init];
NSLog(#"username %#",activeUsername);
newsArticle = [parseQuestionnaire parseXML:myLat:mylong:activeUsername];
[self.tableView reloadData];
[self stopLoading];
}
However this shows the NSLog output as:
LocNews1[6699:707] ViewController username.strUsername is:
As you can see the string has been set in UsernameViewController.m but when I try and call the string back in TestViewController.m is appears to be blank (there is no null in the NSLog, just blank);
What could be causing this?
EDIT: Username.h/m
#import <Foundation/Foundation.h>
#interface Username : NSObject
{
NSString *strUsername;
}
#property (nonatomic, retain) NSString *strUsername;
#end
#import "Username.h"
#implementation Username
#synthesize strUsername;
-(id)init
{
strUsername = [[NSString alloc] init];
return self;
}
#end
Note: Username is declared in both TestViewController.h and UsernameViewController.h like: Username *username;
The username instance variable in that instance of UsernameViewController is completely unrelated to the username instance variable in the instance of TestViewController. You'll need to store the variable in a place that both controllers know about or pass it between them if you want them both to have access. Simply having two variables with the same name doesn't connect them in any way.
This is a sample from book "Cocoa Programming For Mac Os X 3rd(HD)" chapter 7 "Key-Value Coding. Key-Vaule Observing
Here is the code:
Person.h:
#import <Foundation/Foundation.h>
#interface Person : NSObject {
NSString *personName;
float expectedRaise;
}
#property (readwrite, copy) NSString *personName;
#property (readwrite) float expectedRaise;
#end
Person.mm:
#import "Person.h"
#implementation Person
#synthesize expectedRaise;
#synthesize personName;
- (id)init
{
[super init];
expectedRaise = 0.05;
personName = #"New Person";
return self;
}
- (void)dealloc
{
[personName release];
[super dealloc];
}
#end
MyDocument.h:
#import <Cocoa/Cocoa.h>
#interface MyDocument : NSDocument
{
NSMutableArray *employees;
}
#property (retain) NSMutableArray *employees;
#end
MyDocument.mm:
#import "MyDocument.h"
#import "Person.h"
#implementation MyDocument
#synthesize employees;
- (id)init
{
if (![super init])
return nil;
employees = [[NSMutableArray alloc] init];
return self;
}
- (void)dealloc
{
[employees release];
[super dealloc];
}
- (void)windowControllerDidLoadNib:(NSWindowController *) aController
#end
And the sample works fine.(A blank table at first and you can add or delete record).
Now I tried to add some records to the array so that the blank table would have
someting in it at first.
Here's what I'v tried(inside the init method):
[self willChangeValueForKey:#"employees"];
Person *p1 = [[Person alloc] init];
[employees addObject: [NSData dataWithBytes: &p1 length: sizeof(p1)]];
[self didChangeValueForKey:#"employees"];
But when I build and wrong I got the error msg:
[<NSConcreteData 0x422bf0> valueForUndefinedKey:]: this class is not key value coding-compliant for the key personName.
......
Can any one help me out of here? Thanks in advance ^_^
That seems like a very reasonable response... you added NSData to your array named employees; guessing from the names, and from the KVC, you probably meant to add p1 to your array instead. So, try:
[employees addObject:p1];