Problem adding objects to array in iPhone SDK

Question

I'm having a problem with adding objects to an NSArray in iPhone SDK. The problem is that it only adds the last object of my NSDictionary. This is the code:

NSArray * processes = [[UIDevice currentDevice] runningProcesses];
for (NSDictionary * dict in processes){
    runningprocesses = [[NSMutableArray alloc] init];
    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

When I NSLog [dict objectForKey:@"ProcessName"] it shows me all the processes but if I try to add them it only adds the last one. What could be happening?

because In your code, each time the loop iterates, the runningprocesses array is pointing to a new instance. — Mohit
– Mohit, Commented May 14, 2014 at 10:29

Nils Munch · Accepted Answer · 2011-06-24 11:52:38Z

2

I reedited your code as I would suggest you try instead :

NSArray * processes = [[UIDevice currentDevice] runningProcesses];
NSMutableArray *runningprocesses = [[NSMutableArray alloc] initWithCapacity:[processes count]];
for (NSDictionary * dict in processes){
    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

This works for me when I try it :]

answered Jun 24, 2011 at 11:52

Nils Munch

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2 Comments

redent84 Over a year ago

+1: The only answer that uses initWithCapacity: for NSArray creation

Nils Munch Over a year ago

Yes, I'm a "capacity-nazi"... its the only way I can truly trust mutable data on not acting weird.

ageektrapped · Accepted Answer · 2011-06-24 11:54:15Z

0

In your code, each time the loop iterates, the runningprocesses array is pointing to a new instance.

To fix it move your array instantiation outside the for loop:

NSArray * processes = [[UIDevice currentDevice] runningProcesses];
NSMutableArray *runningprocesses = [[NSMutableArray alloc] init];
for (NSDictionary * dict in processes){

    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

answered Jun 24, 2011 at 11:54

ageektrapped

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Comments

Deepak Danduprolu · Accepted Answer · 2011-06-24 12:01:52Z

0

You are trying to allocating "runningprocesses" array every time in the for loop. That is why it would have only one object at the end of for loop. Try replacing this code.

NSArray * processes = [[UIDevice currentDevice] runningProcesses];
runningprocesses = [[NSMutableArray alloc] init];
for (NSDictionary * dict in processes){
    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

This should work.

edited Jun 24, 2011 at 12:01

Deepak Danduprolu

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answered Jun 24, 2011 at 11:55

Deeps

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Comments

Deepak Danduprolu · Accepted Answer · 2011-06-24 12:03:01Z

0

You should move your alloc-init statement outside the for loop. Here is the following code

runningprocesses = [[NSMutableArray alloc] init];
NSArray * processes = [[UIDevice currentDevice] runningProcesses];

for (NSDictionary * dict in processes)
{
    NSString *process = [dict objectForKey:@"ProcessName"];
    [runningprocesses addObject:process];
}

edited Jun 24, 2011 at 12:03

Deepak Danduprolu

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answered Jun 24, 2011 at 12:01

santosh

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