NSUserDefaults返回（空）

Question

I'm a newcomer to NSUserDefaults and am struggling to get my head around something I imagine is probably straightforward for most reading this.

I'm trying to retrieve a mutable array of strings if it exists in NSUserDefaults with the following code:

NSMutableArray *globalAppsArray;

if([[NSUserDefaults standardUserDefaults] objectForKey:@"globalAppsArray"] != nil)
{
    NSLog(@"Array found. Contents: %@", globalAppsArray);        
}
else
{
    globalAppsArray = [[NSMutableArray alloc] initWithCapacity:0];
}

After adding any new data to it I then want to save it:

[[NSUserDefaults standardUserDefaults] setObject:globalAppsArray forKey:@"globalAppsArray"];
[[NSUserDefaults standardUserDefaults] synchronize];

When I relaunch the app, the mutable array is found OK but the contents are null .

Can someone tell me what I'm missing?

Answer 1

It should be something like this:

NSMutableArray *globalAppsArray = [[NSUserDefaults standardUserDefaults] objectForKey:@"globalAppsArray"];

if(globalAppsArray != nil)
{
    NSLog(@"Array found. Contents: %@", globalAppsArray);
}
else
{
    globalAppsArray = [[NSMutableArray alloc] initWithCapacity:0];
}

Answer 2

check your code once,

NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSMutableArray *globalAppsArray = [[defaults objectForKey:@"globalAppsArray"] mutableCopy];
if(globalAppsArray)
    NSLog(@"Array found. Contents: %@", globalAppsArray);
else
    globalAppsArray = [NSMutableArray array];