I have a check box type application, kinda like notes on the iPhone. When the user closes the application and double tabs the home button and deletes the application from the background, the things they have typed also get deleted or reset. I was thinking of calling
[self saveContext];
But that didn't work. WHat should I be calling?
You can usual use something such as NSUserDefaults to save information. Or, you can go another route and save the information in a data structure and write that to a file. There are many easy ways of doing this. For instance, if you want to preserve a checked value, you could do the following:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setBool:YES forKey:"checked"];
[defaults synchronize];
Very simple, and then can be queried across app exits, like so:
if( [defaults boolForKey:"checked"] ) {
//do stuff here
}
Related
I've made a simple save and load app for contacts (first name, second name and phone number) using NSUserDefaults but i need to show this information in a scroll view. could someone please guide me how to do this? code for each IBAction is this:
//this is to save a contact - where does it go? trying to figure that out...
- (IBAction)save:(id)sender {
NSString*saveString = firstName.text;
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:saveString forKey:#"saveString"];
[defaults synchronize];
this is to load the last contact that was saved. where does it load from, i don't know. how to add to it dynamically, need to figure that out. how to log everything on a UIScrollView, pls advise!
- (IBAction)load:(id)sender {
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSString *loadString = [defaults objectForKey:#"saveString"];
[firstName setText:loadString];
NSLog(#"%#", theArray);
basically i need to make a simple phoneBook app for class and make the contact show up as a button on a scroll view once saved. everything works fine except for making contact show up as a button!
i have been working on a app, and needed to store a string. I used this code to set the default:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setValue:CertificateKey.stringValue forKey:#"SavedKey"];
[[NSUserDefaults standardUserDefaults] synchronize];
NSLog(#"%#",[defaults objectForKey:#"SavedKey"]);
I loged it, so i know it saved...well, it showed me the value.
When i open my application, I use this to retrieve the default:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[CertificateKey setStringValue:[defaults objectForKey:#"SavedKey"]];
[CertificateKey setTitleWithMnemonic:[defaults objectForKey:#"SavedKey"]];
[[NSUserDefaults standardUserDefaults] synchronize];
Why will it not get the default value? Did i not completely save it?
Don't quit the application by pressing the stop button in xcode. Instead, quit it by right clicking on the application icon and selecting "Quit".
Edit
Maybe the first time that you execute the application, you want to save some defaults but you don't want to set them the second+ time that the application runs.
For this purpose in some class initialize method register the defaults, like this:
+ (void) initialize
{
NSUserDefaults* defaults= [NSUserDefaults standardUserDefaults];
[defaults registerDefaults: #{} ];
// This case it's an empty dictionary, but you can put whatever you want inside it.
// just convert it to data if it's not an object storable to a plist file.
}
Also, you're using setValue:forKey: , that method is inherited from NSObject. Use setObject:forKey: .
And use finalize if you want to save the defaults at the end:
- (void) finalize
{
// Save the defaults here
}
You might have a problem because you are creating an instance of NSUserDefaults. From what I understand you are supposed to access it like so: [[NSUserDefaults standardUserDefaults] setValue:#"Pikachu" forKey:#"Best Pokemon Ever"]; [[NSUserDefaults standardDefaults] objectForKey:#"Best Pokemon Ever"]; Rather than actually creating an instance of it.
I'm doing an app that lets user to choose language and change it during runtime. I have an issue trying to store desired language. It runs correctly during the same execution the user changes language, but then in next execution, it always gets spanish language (system language). Here is the code I use to store language:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if (sender.tag==1){
[defaults setObject:[NSArray arrayWithObjects:#"ca",#"es", nil] forKey:#"AppleLanguages"];
}else{
[defaults setObject:[NSArray arrayWithObjects:#"es",#"ca", nil] forKey:#"AppleLanguages"];
}
[defaults synchronize];
Many thanks
The system will override the value of AppleLanguages every time your app gets started.
A solution would be to store your desired languages in a separate NSUserDefaults entry and load them (write them into AppleLanguages) at every app startup.
Hope this helps
How would I check if it is the first launch of of my application using NSUserDefaults and running some code for the first time my app opens?
This should point you in the right direction:
static NSString* const hasRunAppOnceKey = #"hasRunAppOnceKey";
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
if ([defaults boolForKey:hasRunAppOnceKey] == NO)
{
// Some code you want to run on first use...
[defaults setBool:YES forKey:hasRunAppOnceKey];
}
The NSUserDefaults answer is the first thing that popped in my head, but upon reflection I will make another suggestion. A bit more work, but it's worth considering. The motive is: sometimes when troubleshooting an app, Apple recommends deleting that app's plist file. It's a fairly ubiquitous troubleshooting technique. I would recommend storing your boolean in your plist file instead of NSUserDefaults.
Disclaimer: I only do iOS development, so I'm not sure how NSUserDefaults and plists interact on the Mac, and I don't know what all is involved in getting your plist to live in ~/Library/Application\ Support/Preferences/com.mycompany.MyAppName.plist
Anyway, I imagine what this requires is having some code which can actually author a "fresh" plist (probably a copy from a template file in your bundle), and you app does this if it launches and does not see a plist. The default plist should not include the flag which lets your users skip the 'first time' code, but if they have opened the app before, and then delete the plist, they should get default behavior back.
This is an important behavior to support where possible, to aide our users if our app ever gives them trouble.
if (![[NSUserDefaults standardUserDefaults] boolForKey:#"hasBeenLaunched"]) {
// Run code on the first launch only ...
[defaults setBool:YES forKey:#"hasBeenLaunched"];
}
You can use NSUserDefaults to save bools, integers, objects into the program and have them available whenever you open it. You can use 'boolForKey' to set a flag called "hasBeenLaunched". By default, this value will be NO when not set. Once you change it to YES, the code in the if condition will never be executed again.
In your main controller class, implement something like this:
static NSString * const MDFirstRunKey = #"MDFirstRun";
#implementation MDAppController
+ (void)initialize {
NSMutableDictionary *defaults = [NSMutableDictionary dictionary];
[defaults setObject:[NSNumber numberWithBool:YES] forKey:MDFirstRunKey];
[[NSUserDefaults standardUserDefaults] registerDefaults:defaults];
// the following if on Mac and is necessary:
[[NSUserDefaultsController sharedUserDefaultsController] setInitialValues:defaults];
}
- (void)applicationDidFinishLaunching:(NSNotification *)notification {
BOOL firstRun = [[[NSUserDefaults standardUserDefaults]
objectForKey:MDFirstRunKey] boolValue];
if (firstRun) {
// do something
[[NSUserDefaults standardUserDefaults] setObject:
[NSNumber numberWithBool:NO] forKey:MDFirstRunKey];
} else {
// do something else
}
}
#end
The +initialize class method is called before an instance of the class it's found in is created; in other words, it is called very early on, and is a good place to set up your default values.
See Preferences and Settings Programming Guide: Registering Your App's Default Preferences for more info.
I am trying to use NSUser Deafault in my application user have tp fillup 4 UITextFields. I am trying to save the fields so that on subsequent runs of the program that whatever they previously put will already be displayed in those UITextFields so the wont have to re-input it in - unless they want to edit something in which case they still have that option. I think that I have figured out a good way to save the strings using NSUserDefaults but now I am trying to figure out how to have those fields populate a UITextField - it doesnt seem as easy as if they were UILabels. This is the route I am attempting:
Now my value is being saved in nsuserDefalut,but hot how to fetch dat value next time(when i re start application (null appear on the uitext field)) ..I am trying this cods
NSUserDefaults *userData = [NSUserDefaults standardUserDefaults]; //Hooks.
NSString *placeHolderName = [userData stringForKey:#"name"];
urltextFieldNormal.text = placeHolderName;
Do you remember to sync NSUserDefaults when you save the strings?
[[NSUserDefaults standardUserDefaults] setObject:#"Hello mister nick" forKey:#"alarmsArray"];
[[NSUserDefaults standardUserDefaults] synchronize];
Cheers mate...