I have switches in my app that stores position by standardUserDefaults, but when app starts for first time all my switches are in OFF position. How can I set them to ON by default?
Save
NSUserDefaults *defs1 = [NSUserDefaults standardUserDefaults];
[defs1 setBool: blackSwitch.on forKey: #"blackKey"];
[[NSUserDefaults standardUserDefaults] synchronize];
Load
NSUserDefaults *defs1 = [NSUserDefaults standardUserDefaults];
blackSwitch.on = [defs1 boolForKey: #"blackKey"];
First of all
Do the following
NSUserDefaults *defs1 = [NSUserDefaults standardUserDefaults];
BOOL isOn = [defs1 boolForKey: #"blackKey"];
if(isOn) NSLog(#"isOn");
Second asure that blackSwitch is not nil
if(blackSwitch) NSLog(#"blackSwitch is not nil");
If blackswitch is nil, that means that you are still in early stage of view controller initialization, you should move the code that sets it on to viewDidLoad or viewWillAppear
For setting default values please use this code
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSNumber *testValue = [NSNumber numberWithBool:YES];
NSDictionary *appDefaults = [[NSDictionary alloc] initWithObjectsAndKeys:
testValue, #"blackKey", nil];
[defaults registerDefaults:appDefaults];
[appDefaults release];
Use the NSUserDefaults method registerDefaults to pass a default value of 'true' along with your #"blackKey" key. This will ensure that #"blackKey" is set to ON until the user makes a change to it themselves.
Related
I am using NSUserDefaults to store my app settings/configuration.
The code responsible to saving defaults is below:
NSUserDefaults * standardUserDefaults = [NSUserDefaults standardUserDefaults];
// saving settings
[standardUserDefaults setObject:address.text forKey:#"URL"];
[standardUserDefaults setObject:username.text forKey:#"username"];
[standardUserDefaults setObject:password.text forKey:#"password"];
// synchronize the settings
[standardUserDefaults synchronize];
Indeed, the settings seem to have been saved. I open plist file from Libary/Preferences and see that the values are saved. I see those after my method is finished working and [even after] after closing the app.
My problem: whenever I start my app again, the saved values are gone from the plist file[the keys are still present], and I obviously cannot load my preferences.
Please advise.
You can use to save Settings:
NSMutableDictionary *dictSetting = [[NSMutableDictionary alloc] init];
[dictSetting setValue:address.text forKey:#"URL"];
[dictSetting setValue:username.text forKey:#"username"];
[dictSetting setValue:password.text forKey:#"password"];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:dictSetting forKey:#"SETTINGS"];
[defaults synchronize];
to Retrive Setting:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSDictionary *dictSettingData = [defaults objectForKey:#"SETTINGS"];
NSString *url = [dictSettingData valueForKey:#"URL"];
NSString *username = [dictSettingData valueForKey:#"username"];
NSString *password = [dictSettingData valueForKey:#"password"];
I have two completely separate tasks being carried out but somehow they seem to connect.
In ViewController 1, I have:
NSString *foo = #"foo";
NSUserDefaults *default1 = [NSUserDefaults standardUserDefaults]
[default1 setObject:foo forKey:#"foo"];
[default1 synchronize];
and when I do:
NSLog(#"%#", [[NSUserDefaults standardUserDefaults] objectForKey:#"foo"]);
The value printed is what I expect it to be.
In ViewController 2, I have:
NSString *bar = #"bar";
NSUserDefaults *default2 = [NSUserDefaults standardUserDefaults]
[default2 setObject:bar forKey:#"bar"];
[default2 synchronize];
And same again when I NSLog it, the value is what I expect it to be.
But somehow when i try to print object #"foo" again it gives me the value for the second object, in this case #"bar"
Any guidance on why my original value is being overridden by the second value even tough the variable/key names are different in the 2 classes?
You are doing this for both:
[foo setObject:bar forKey:#"bar"];
Shouldn't it be:
[defaults1 setObject:foo forKey:#"foo"];
And
[defaults2 setObject:bar forKey:#"bar"];
There is however, a greater problem:
NSString *foo = #"foo";
NSUserDefaults *default1 = [NSUserDefaults standardUserDefaults];
[default1 setObject:foo forKey:#"foo"];
[default1 synchronize];
NSLog(#"%#", [[NSUserDefaults standardUserDefaults] objectForKey:#"foo"]);
NSString *bar = #"bar";
NSUserDefaults *default2 = [NSUserDefaults standardUserDefaults];
[default2 setObject:bar forKey:#"bar"];
[default2 synchronize];
NSLog(#"%#", [[NSUserDefaults standardUserDefaults] objectForKey:#"bar"]);
Will work properly, however you're creating defaults1 and defaults2 which are both instances of standard defaults, so:
NSUserDefaults * defaults1 = [NSUserDefaults standardUserDefaults];
NSUserDefaults * defaults2 = [NSUserDefaults standardUserDefaults];
[NSUserDefaults standardUserDefaults];
Are all pointers to the standardUserDefaults singleton. So they are identical instances. You could simply do:
NSUserDefaults *standardDefaults = [NSUserDefaults standardUserDefaults];
NSString *foo = #"foo";
[standardDefaults setObject:foo forKey:#"foo"];
NSString *bar = #"bar";
[standardDefaults setObject:bar forKey:#"bar"];
[standardDefaults synchronize];
NSLog(#"%#", [[NSUserDefaults standardUserDefaults] objectForKey:#"foo"]);
NSLog(#"%#", [[NSUserDefaults standardUserDefaults] objectForKey:#"bar"]);
You can print out the entire set of user defaults with code like this
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSDictionary *dictionary = [defaults dictionaryRepresentation];
NSLog( #"%#", dictionary );
Note that Apple puts lots of garbage in the user defaults, so you'll have to scroll to the end to see foo and bar. I'm guessing that you have a typo in code that you haven't shown us, and either foo is being overwritten, or foo simply isn't being displayed properly.
The current code in your question (after 1 edit) is all good and should work correctly.
Hi I am using uislider and get the values in label. now i try to save the slider values. I don't know how to do this. If anybody knows please share the code. This is my code for slider changed.
-(IBAction)sliderChanged:(id)sender
{
UISlider *slider = (UISlider *)sender;
if((int)slider.value % 10 == 0)
{
sliderLabel.text = [[NSString alloc] initWithFormat:#"Value of:%d", (int)slider.value];
}
}
You can use NSUserDefault for storing the slider value.
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:sliderLabel.text forKey:#"Slider"];
[defaults synchronize];
You can retrieve the data like:
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
NSString *strValue = [defaults objectForKey:#"Slider"];
myLabel.text = strValue != nil ? strValue : #"No Value";
The above code is saving the sliderLabel to the NSUserDefault. If you want to store the slider value in the form of float then use:
[defaults setObject:[NSNumber numberWithFloat:slider.value] forKey:#"Slider"];
Retreive it like:
NSNumber *strValue = [defaults objectForKey:#"Slider"];
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:[NSNumber numberWithFloat:slider.value] forKey:#"sliderValue"];
I believe you should store the value as a float (the original type for a UISlider value), it's just cleaner, and you'll probably want to reuse the float value to set back your slider when reopening the screen with something like:
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
[self.slider setValue:[[defaults objectForKey#"sliderValue"] floatValue]];
How to know whether NSUserDefaults contains any value?How to check whether its empty?
There isn't a way to check whether an object within NSUserDefaults is empty or not.
However, you can check whether a value for particular key is nil or not.
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
NSObject * object = [prefs objectForKey:#"your_particular_key"];
if(object != nil){
//object is there
}
NSUserDefaults *data = [NSUserDefaults standardUserDefaults];
NSString *string = [data objectForKey:#"yourKey"];
if(string==nil)
NSlog(#"nil")
Take a look at NSUserDefault documentation
// For saving the values
NSUserDefaults *userDefaults = [NSUserDefaults standardUserDefaults];
// saving an NSString
[userDefaults setObject:#"Ttest" forKey:#"key"];
// --- For Retrieving
NSUserDefaults * userDefaults = [NSUserDefaults standardUserDefaults];
// getting an NSString
NSString *myString = [userDefaults stringForKey:#"key"];
To check whether a specific value is set or not, no matter of its location (global or application's), check the returned value of -[NSUserDefaults objectForKey:]
id obj = [[NSUserDefaults standardUserDefaults] objectForKey:#"My-Key-Name"];
if (obj != nil) {...}
To check if the application (bundle) has any settings stored in user defaults:
NSUserDefaults* sdu = [NSUserDefaults standardUserDefaults];
NSString* bundleId = [[NSBundle mainBundle] bundleIdentifier];
NSDictionary* mainBundleSettings = [sdu persistentDomainForName:bundleId];
NSLog(#"%#", mainBundleSettings);
If you are interested in all possible values for which -[NSUserDefaults objectForKey:] will return something, including system global settings, simply call
NSDictionary* allPossibleSettings = [sdu dictionaryRepresentation];
NSUserDefaults is never empty. It combines global settings, bundle's settings, temporary data and maybe something else. For example, if you call:
[[NSUserDefaults standardUserDefaults] objectForKey:#"NSBoldSystemFont"]
you will get the #"LucidaGrande-Bold" string value which will be taken from global settings, even when your application has never set this value.
This question already has answers here:
Closed 11 years ago.
Possible Duplicate:
How can I save and load the alpha values of a UIButton in an app?
I would like to save the state of the UIButton (e.g. its alpha value and whether it is hidden or not) and this would then load up when the user quits and reloads the app.
I've tried some bits of code with NSUserDefaults but with no luck.
Could somebody help with some sample code so that I can save and load the button's state?
Thanks,
James
Related to Shaharyar's answer (i don't know how to comment):
in this case you need to use NSNumber.
[[NSUserDefaults standardUserDefaults] setValue:[NSNumber numberWithFloat:SOME_FLOAT] forKey:KEY];
because float is not an object, but NSNumber is one.
EDITED:
1) To make sure your defaults are created after the application runs at first time:
in your AppDelegate's initialize-method:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSDictionary *appDefaults = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithFloat:SOME_FLOAT], #"YOUR_KEY",
nil];
[defaults registerDefaults:appDefaults];
2) Updating defaults after:
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[prefs setFloat:FLOAT_VALUE forKey:#"YOUR_KEY"];
[prefs synchronize];
3) Read defaults:
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
float FLOAT_VALUE = [prefs floatForKey:#"YOUR_KEY"];
Can you post some of the code?
NSUserDefaults is the place to store such information..
Assumption:
Did you make a call to [NSUserDefaults synchronize] after setting the values?
Code:
// Setting a value
[[NSUserDefaults standardUserDefaults] setValue:VALUE forKey:KEY];
[[NSUserDefaults standardUserDefaults] synchronize];
// Getting a value
NSString *var1 = [[NSUserDefaults standardUserDefaults] valueForKey:KEY];
In your case it would be:
// Setting a value
[[NSUserDefaults standardUserDefaults] setFloat:VALUE forKey:KEY];
[[NSUserDefaults standardUserDefaults] synchronize];