Save string to the NSUserDefaults?

Question

How to save a string into the NSUserDefaults?

Solution 1

NSString *valueToSave = @"someValue";
[[NSUserDefaults standardUserDefaults] setObject:valueToSave forKey:@"preferenceName"];
[[NSUserDefaults standardUserDefaults] synchronize];

to get it back later

NSString *savedValue = [[NSUserDefaults standardUserDefaults]
    stringForKey:@"preferenceName"];

Solution 2

more precisely

-(void)saveToUserDefaults:(NSString*)myString
{
    NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];

    if (standardUserDefaults) {
        [standardUserDefaults setObject:myString forKey:@"timestamps"];
        [standardUserDefaults synchronize];
    }
}

Solution 3

Here's how to do the same with Swift;

var valueToSave = "someValue"
NSUserDefaults.standardUserDefaults().setObject(valueToSave, forKey: "preferenceName")

To get it back later;

if let savedValue = NSUserDefaults.standardUserDefaults().stringForKey("preferenceName") {
    // Do something with savedValue
}

In Swift 3.0

var valueToSave = "someValue"
UserDefaults.standard.set(valueToSave, forKey: "preferenceName")

if let savedValue = UserDefaults.standard.string(forKey: "preferenceName") {

}

Solution 4

Something like this:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// saving an NSString
[prefs setObject:@"TextToSave" forKey:@"keyToLookupString"];

Then to retrieve:

NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];

// getting an NSString
NSString *myString = [prefs stringForKey:@"keyToLookupString"];

You should really check out Apple's NSUserDefaults Class Reference and also maybe this tutorial: iPhone Programming Tutorial – Saving/Retrieving Data Using NSUserDefaults

Solution 5

Do not forget this statement because otherwise it may not always work:

[standardUserDefaults synchronize];

View more solutions

Comments

[Jayprakash Dubey]

Try this : jayprakashdubey.blogspot.in/2014/07/nsuserdefault-usage.html

[Ε Г И І И О]

If you are looking for Swift, then I have added an answer.

[jbrennan]

There is no need to perform the nil check for standardUserDefaults object. It is perfectly fine to send messages to nil in Objective-C.

[PostCodeism]

But more importantly he included "synchronize" - NSUserDefaults is very erratic if you don't call this!

[iOS.Lover]

Is there any way to save this string base on specific date ? thanks but your code works as same as mine , I create a custom calendar app which user can write their notes in it , for example in 3 Feb user writes something and this text should be saved in 3 Feb , and when user move to the another days he/she could write something else accruing to thad day date

[Scott Roepnack]

standardUserDefaults synchronize fixed some strange bugs for me, thanks!

[eliocs]

The reference talks about the synchronize method: "use this method only if you cannot wait for the automatic synchronization (for example, if your application is about to exit)" - NSUserDefaults Class Reference

[fs_tigre]

For some reason the saving part didn't work properly until I called the synchronize method. NSString *valueToSave = @"someValue";[[NSUserDefaults standardUserDefaults]setObject:valueToSave forKey:@"preferenceName"]; [[NSUserDefaults standardUserDefaults]synchronize

[Basil Bourque]

@jbrennan While your comment is technically correct, this answer is helpful in case you are writing something important and want to be sure it was saved successfully. Furthermore, in that regard, it would be good to test (rather than ignore) the return value of synchronize. The doc says: YES if the data was saved successfully to disk, otherwise NO.

[Juan Boero]

[[NSUserDefaults standardUserDefaults] synchronize]; is getting deprecated

[Akshansh Thakur]

Thanks, since the original question was for swift, +1

[Roy Falk]

I'm having trouble with my cynicism detector after lunch. The original question was asked in 2010. I therefore upvoted this since Swift is the way to go today.

[deniz]

As of iOS 12, calling synchronize is no longer needed: stackoverflow.com/a/57218546/12484