I have OJTest.h containing:
#property (nonatomic) int testVal;
In ViewController.h:
#import "OJTest.h"
#property (strong, nonatomic) OJTest *testObject;
In ViewController.m:
-(void)viewDidLoad
{
[super viewDidLoad];
self.testObject.testVal = 100;
NSLog(#"%i", self.testObject.testVal);
}
Yet the console prints 0. What am I missing/misunderstanding?
Your testObject is not being created.
Try the following in your viewDidLoad:
self.testObject = [[OJTest alloc] init];
self.testObject.testVal = 100;
Related
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
I'm trying to make a very simple iOS app where an integer is created within a MutableArray.
The integer must present itself in an label in a Custom ViewController. Here is my code:
#interface Photo : NSObject
#property (nonatomic) NSString *name;
#property (nonatomic) NSString *filename;
#property (nonatomic) NSString *naam;
#property (nonatomic) int leeftijd;
#property (nonatomic) NSString *herkomst;
#property (nonatomic) NSString *club;
#end
My Custom TableViewController with an mutableArray.
#interface PhotosTableViewController () {
NSMutableArray *photos;
}
#end
#implementation PhotosTableViewController
- (id)initWithStyle:(UITableViewStyle)style
{
self = [super initWithStyle:style];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
self.title = #"Soccer Players";
// Create an array
photos = [[NSMutableArray alloc]init];
Photo *pic = [[Photo alloc]init];
pic.name = #"Ronaldo";
pic.filename = #"ronaldo";
pic.naam = #"Christano Ronaldo";
pic.leeftijd = 29;
pic.herkomst = #"Portugal";
pic.club = #"Real Madrid";
[photos addObject:pic];
And at last my Custom ViewController
#interface DisplayViewController ()
#property (weak, nonatomic) IBOutlet UIImageView *currentImage;
#property (weak, nonatomic) IBOutlet UILabel *nameLabel;
#property (weak, nonatomic) IBOutlet UILabel *ageLabel;
#property (weak, nonatomic) IBOutlet UILabel *countryLabel;
#property (weak, nonatomic) IBOutlet UILabel *clubLabel;
#end
#implementation DisplayViewController
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[super viewDidLoad];
UIImage *image = [UIImage imageNamed:self.currentPhoto.filename];
[self.currentImage setImage:image];
self.nameLabel.text = [self.currentPhoto naam];
self.ageLabel.text = [self.currentPhoto leeftijd];
self.countryLabel.text = [self.currentPhoto herkomst];
self.clubLabel.text = [self.currentPhoto club];
}
Not sure what i'm doing wrong. I gave the integer a Property , gave it a amount en declared it in a label. Must be something very stupid, but can't see the solution on the web.
Thanks for your help!
You should 'convert' int to string:
self.ageLabel.text = [NSString stringWithFormat:#"%d", [self.currentPhoto leeftijd]];
Integer is not auto converted to NSString. Change
self.ageLabel.text = [self.currentPhoto leeftijd];
to
self.ageLabel.text = [[self.currentPhoto leeftijd] description];
or to
self.ageLabel.text = [NSString stringWithFormat:#"%i", [self.currentPhoto leeftijd]];
Lable only show NSString so you convert your int to NSString..
self.ageLabel.text = [NSString stringWithFormat:#"%d", [self.currentPhoto leeftijd]];
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];
In my viewController.m I have this code:
self.movie = [[myMovie alloc]init];
self.movie.name = #"Iron man 2"; \\this line leaks
...
nameLbl = [[UILabel alloc] initWithFrame:CGRectMake(30, 20, 200, 20)]; \\this line leaks
nameLbl.backgroundColor = [UIColor clearColor];
In viewController.h I have this code:
#interface ViewController : UIViewController
{
myMovie * movie;
UILabel * nameLbl;
}
#property (nonatomic, retain) myMovie * movie;
#property (nonatomic, retain) UILabel * nameLbl;
And myMovie.h:
{
NSString* name;
}
#property (nonatomic, retain) NSString* name;
myMovie.m:
#import "myMovie.h"
#implementation myMovie
#synthesize name, gross, desc;
-(void) dealloc
{
self.name = nil;
self.gross = nil;
self.desc = nil;
[super dealloc];
}
#end
Of course this is only the necessary code. I can't figure out why it is leaking. I don't know if this is the cause but my application crashes.
The line that's leaking is the one above: self.movie = [[myMovie alloc]init];
Change it to self.movie = [[[myMovie alloc]init] autorelease]; or add [self.movie release]; as the line immediately afterwards.
i tried to follow this tutorial:
http://www.youtube.com/watch?v=L-FK1TrpUng&feature=related
around 00:39:00.
Theres a counter which recognizes every switch to the second view controller and counts it.
The number of view switches should be shown on the second view controller.
But it doesn't work, thats the code:
Test2ViewController.h
#interface Test2ViewController : UIViewController <UITextFieldDelegate> {
UINavigationController *navController;
Test21ViewController *test21View;
NSString *text;
IBOutlet UITextField *textField1;
}
#property(nonatomic, retain) UITextField *textField1;
#property (nonatomic, retain) UINavigationController *navController;
#property (copy) NSString *text;
-(IBAction)pushViewController:(id)sender;
#end
Test2ViewController.m:
#import "Test2ViewController.h"
#import "Test21ViewController.h"
#implementation Test2ViewController
#synthesize textField1, navController, text;
-(IBAction)pushViewController:(id)sender {
static int count = 1;
Test21ViewController *test21ViewController = [[Test21ViewController alloc] init];
[self.navigationController pushViewController:test21ViewController animated:YES];
test21ViewController.label = [NSString stringWithFormat:#"Pushed %d", count];
count++;
}
Test21ViewController.h:
#interface Test21ViewController : UIViewController {
UINavigationController *navController;
NSString *label;
IBOutlet UILabel *textLabel;
UITextField *tF1;
}
#property (copy) NSString *label;
#property (nonatomic, retain) UINavigationController *navController;
#property(nonatomic,retain)UITextField *tF1;
-(IBAction)feldeingabe:(id)Sender;
#end
Test21ViewController.m:
#implementation Test21ViewController
#synthesize label;
- (void)viewDidLoad {
textLabel.text = label;
}
Any ideas why it doesn't work?
Thanks in advance
Code for the second question:
static int count = 1;
Test2ViewController *test2ViewController;
test2ViewController.label = [NSString stringWithFormat:#"Pushed %d !!!!!", count];
[[self navigationController] popViewControllerAnimated:NO];
count++;
CURRENT CODE:
#import "Test21ViewController.h"
#implementation Test21ViewController
#synthesize navController, text, parentView;
-(IBAction)pushViewController2:(id)sender {
Test2ViewController *test2ViewController;
static int count = 1;
test2ViewController.parentView = self;
test2ViewController.label = [NSString stringWithFormat:#"Pushed %d !!!!!", count];
[self.navigationController pushViewController:test2ViewController animated:YES]; count++;
}
For the second problem (passing a string from child to parent);
Test2ViewController.h
#interface Test2ViewController : UIViewController <UITextFieldDelegate> {
NSString *receiverPropertyFromChild;
}
#property(nonatomic, retain) NSString *receiverPropertyFromChild;
Test2ViewController.m:
-(IBAction)pushViewController:(id)sender {
static int count = 1;
Test21ViewController *test21ViewController = [[Test21ViewController alloc] init];
test21ViewController.label = [NSString stringWithFormat:#"Pushed %d", count];
test21ViewController.parentView = self;
[self.navigationController pushViewController:test21ViewController animated:YES];
count++;
}
Test21ViewController.h:
#class Test2ViewController;
#interface Test21ViewController : UIViewController {
Test2ViewController *parentView;
}
#property (nonatomic, assign) Test2ViewController *parentView;
Test21ViewController.m
-(IBAction)goToTest2ViewController:(id)sender {
parentView.receiverPropertyFromChild = #"the text you want to pass";
[self.navigationController popViewControllerAnimated:YES];
count++;
}
can you try:
Test21ViewController *test21ViewController = [[Test21ViewController alloc] init];
test21ViewController.label = [NSString stringWithFormat:#"Pushed %d", count];
[self.navigationController pushViewController:test21ViewController animated:YES];
I swapped the last two lines. It could be that you are setting the label after viewDidLoad has already been called, thus not setting the value in the label.
That said, it is better to pass the string as an init parameter, not as a property and then set in viewDidLoad.
edit:
To set it as init parameter, you need to create a new init method to accept that parameter.
- (id) initWithString:(NSString *)labelParam {
self = [super init];
if (self) {
this.label = labelParam;
}
return self;
}