Can't NSLog my objects in an array

Question

I have an array(taskDays) which I have stored in to class
which contains an array(datedTask) and a NSdate(deadline), in the class array I store another class(datedTask obj) which contains a
NSString(title) and a NSDate(duedate).
When I try to NSLog deadline from main it works but when I try to NSLog
title or duedate xcode crashes.
I have included a picture so you guys can check it out.
If you want I can upload my code somewhere because I really don't know
which code to include here.

Thanks in advance!

diagram

Included the NSLog code since I think it might be the problem there:

NSLog(@"%@", [taskDay[0] title); //Makes stuff crash
NSLog(@"%@", [taskDay[0] datedTask); //How would I code to access the
                                     //title in dated task?

LIUTaskDay.h

#import <Foundation/Foundation.h>
@class LIUDatedTask;

@interface LIUTaskDay : NSObject

@property (nonatomic, copy) NSArray *datedTask;
@property (nonatomic) NSDate *deadline;
- (void)addDatedTask:(LIUDatedTask *)d;



@end

LIUTaskDay.m

#import "LIUTaskDay.h"
#import "LIUDatedTask.h"

@interface LIUTaskDay ()
{
    NSMutableArray *_datedTask;
}

@end



@implementation LIUTaskDay

- (void)setDatedTask:(NSArray *)d {
    _datedTask = [d mutableCopy];
}

- (NSArray *)datedTask {
    return [_datedTask copy];
}

- (void)addDatedTask:(LIUDatedTask *)d {
    // Is datedTask nil?
    if (!_datedTask) {
        //Create the array
        _datedTask = [[NSMutableArray alloc]init];
    }
    [_datedTask addObject:d];
    d.taskDay = self;

}

@end

LIUDatedTask.h

#import <Foundation/Foundation.h>
#import "LIUSimpleTask.h"
@class LIUTaskDay;

@interface LIUDatedTask : LIUSimpleTask

@property (nonatomic) NSDate *dueDate;
@property (nonatomic) NSDate *completedDate;
@property (nonatomic, weak) LIUTaskDay *taskDay;


- (instancetype) initWithTitle:(NSString *)t
                 initWithDueDate:(NSDate *)dd;

@end

LIUDatedTask.m

#import "LIUDatedTask.h"
#import "LIUTaskDay.h"

@implementation LIUDatedTask

- (instancetype) initWithTitle:(NSString *)t
               initWithDueDate:(NSDate *)dd;
{

    if (self = [super initWithTitle:t]) {
        _dueDate = [dd copy];
    }

    return self;



}

- (void)taskCompleted
{
    [super taskCompleted];

    _completedDate = [NSDate date];

}


@end

main.m

#import <Foundation/Foundation.h>
#import "LIUDatedTask.h"
#import "LIUTaskDay.h"

int main(int argc, const char * argv[]) {
    @autoreleasepool {

        NSDateComponents *components;

        NSDate *date;

        NSCalendar *gregorian;

        NSMutableArray *taskDay = [NSMutableArray array];

        NSString *string = [NSString stringWithFormat:@"Bok1"];

        components = [NSDateComponents new];
        [components setYear:2016];
        [components setDay:21];
        [components setMonth:1];

        gregorian = [[NSCalendar alloc]initWithCalendarIdentifier:NSCalendarIdentifierGregorian];

        date = [gregorian dateFromComponents:components];

        LIUDatedTask *tmpLIUDatedTask = [[LIUDatedTask alloc]initWithTitle:string initWithDueDate:date];

        LIUTaskDay *tmpLIUTaskDay = [[LIUTaskDay alloc]init];

        [tmpLIUTaskDay addDatedTask:tmpLIUDatedTask];


        components = [NSDateComponents new];
        [components setYear:2017];
        [components setDay:2];
        [components setMonth:2];

        gregorian = [[NSCalendar alloc]initWithCalendarIdentifier:NSCalendarIdentifierGregorian];

        date = [gregorian dateFromComponents:components];

        tmpLIUTaskDay.deadline = date;

        [taskDay addObject:tmpLIUTaskDay];

        //NSLog(@"%@, %@, %@", [day1[0] title],[day1[0] dueDate],[day1[0] deadline]);
        NSLog(@"%@", [taskDay[0] title]);



    }
    return 0;
}

Here is the crash log:

2016-01-10 13:26:41.749 chrjo564_Ny[1072:41244] -[LIUTaskDay title]: unrecognized selector sent to instance 0x100603220
2016-01-10 13:26:41.751 chrjo564_Ny[1072:41244] * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '- [LIUTaskDay title]: unrecognized selector sent to instance 0x100603220'
* First throw call stack:
(
0 CoreFoundation 0x00007fff8bd2003c exceptionPreprocess + 172
1 libobjc.A.dylib 0x00007fff8a2fe76e objc_exception_throw + 43
2 CoreFoundation 0x00007fff8bd230ad - [NSObject(NSObject) doesNotRecognizeSelector:] + 205
3 CoreFoundation 0x00007fff8bc68e24 ___forwarding_ + 1028
4 CoreFoundation 0x00007fff8bc68998 _CF_forwarding_prep_0 + 120 5 objclabb4-chrjo564_Ny 0x0000000100002090 main + 816
6 libdyld.dylib 0x00007fff8a4ee5c9 start + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException
(lldb)

The most significant information is [LIUTaskDay title]: unrecognized selector sent. That means somewhere the message title is sent to LIUTaskDay which doesn't respond to that message.What is LIUTaskDay? — vadian
LIUTaskDay is the class that contains an array and NSDate, In the array I will store the class which contains the title and due date. I have update with my NSLog which might be the problem. — MrNaitX
The object at index 0 of the taskDay array obviously doesn't have a method or property title. — vadian
no the title lies in the datedTask which lies in the array in taskDay. But how do I access title in datedTask then? — MrNaitX
Don't say no, the compiler isn't mistaken. Maybe it's` [[taskDay[0] datedTask] title]` — vadian

xi.lin xi.lin · Accepted Answer · 2016-01-10T13:54:12

You taskDay is an array for LIUTaskDay class.

Your LIUDatedTask is stored in the _datedTask array of LIUTaskDay.

To access LIUDatedTask object, you need to call datedTask method of LIUTaskDay.

So taskDay[0] is tmpLIUTaskDay.

[taskDay[0] datedTask] is the task array.

[taskDay[0] datedTask][0] is the tmpLIUDatedTask.

NSLog(@"%@", [[taskDay[0] datedTask][0] title]) is what you want.

You may use generic type for the NSArray to help you. Something like NSMutableArray<LIUDatedTask *>.

And you may want to follow some naming convention.

Can't NSLog my objects in an array

2 Answers