I've got some settings saved in my Settings.bundle, and I try to use them in application:didFinishLaunchingWithOptions, but on a first run on the simulator accessing objects by key always returns nil (or 0 in the case of ints). Once I go to the settings screen and then exit, they work fine for every run thereafter.
What's going on? Isn't the point of using default values in the Settings.bundle to be able to use them without requiring the user to enter them first?
If I got your question right, in your app delegate's - (void)applicationDidFinishLaunching:(UIApplication *)application, set the default values for your settings by calling
registerDefaults:dictionaryWithYourDefaultValues
on [NSUserDefaults standardUserDefaults]
- (void)applicationDidFinishLaunching:(UIApplication *)application {
NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
NSDictionary *dict = [NSDictionary dictionaryWithObjectsAndKeys:
[NSNumber numberWithInt:3], #"SomeSettingKey",
#"Some string value", #"SomeOtherSettingKey",
nil];
[ud registerDefaults:dict];
}
These values will only by used if those settings haven't been set or changed by previous executions of your application.
As coneybeare said "You should detect if it is the first load, then store all your defaults initially."
On applicationDidFinishLaunching try to set default value in your preference.
Here is the sample:
NSUserDefaults *defaults =[NSUserDefaults standardUserDefaults];
if([defaults objectForKey:#"YOUR_KEY"] == nil)
{
[defaults setValue:#"KEY_VALUE" forKey:#"YOUR_KEY"];
}
When application will run second time it will come with KEY_VALUE for YOUR_KEY.
Thanks,
Jim.
Isn't the point of using default
values in the Settings.bundle to be
able to use them without requiring the
user to enter them first?
No. The point of the settings bundle is to give the user a place to edit all 3rd Party app settings in a convenient place. Whether or not this centralization is really a good idea is a User Experience issue that is off topic.
To answer your question, you should detect if it is the first load, then store all your defaults initially.
And while we are on the subject, I would also check out In App Settings Kit as it provides your app with a simple way to display your app settings in both places (in-app and Settings.app) with minimal code.
The values in the Settings.bundle are intended for the Settings app to able to fill in default values for your app. They are not used by your own app.
But you can set defaults yourself with the registerDefaults: method of NSUserDefaults. This will not actually set them on disk but just give "defaults for the defaults": they are used when no value has been set by the user yet.
Setting registerDefaults: must be done before any use of the default values. The "applicationDidFinishLaunching:" method that others suggested for this, is too late in most cases. By the time "applicationDidFinishLaunching:" is called, your views have already been loaded from the nib files, and their "viewDidLoad:" methods have been called. And they may typically read user defaults.
To guarantee that the defaults are set before first use, I use the following utility class, which loads the values from the Root.plist file and sets them with "registerDefaults:". You use this class to read user defaults instead of "[NSUserDefaults standardUserDefaults]". Use "[Settings get]" instead.
As a bonus, it also contains a registration method for user default change notifications, because I always forget how that is done.
#import "Settings.h"
#implementation Settings
static bool initialized = NO;
+ (void) setDefaults
{
NSString *bundlePath = [[NSBundle mainBundle] bundlePath];
NSString *settingsBundlePath = [bundlePath stringByAppendingPathComponent:#"Settings.bundle"];
NSBundle *settingsBundle = [NSBundle bundleWithPath:settingsBundlePath];
NSString *settingsPath = [settingsBundle pathForResource:#"Root" ofType:#"plist"];
NSDictionary *settingsDict = [NSDictionary dictionaryWithContentsOfFile:settingsPath];
NSArray *prefSpecifierArray = [settingsDict objectForKey:#"PreferenceSpecifiers"];
NSMutableDictionary *appDefaults = [[NSMutableDictionary alloc] init];
for (NSDictionary *prefItem in prefSpecifierArray)
{
NSString *key = [prefItem objectForKey:#"Key"];
if (key != nil) {
id defaultValue = [prefItem objectForKey:#"DefaultValue"];
[appDefaults setObject:defaultValue forKey:key];
}
}
// set them in the standard user defaults
[[NSUserDefaults standardUserDefaults] registerDefaults:appDefaults];
if (![[NSUserDefaults standardUserDefaults] synchronize]) {
NSLog(#"Settings setDefaults: Unsuccessful in writing the default settings");
}
}
+ (NSUserDefaults *)get
{
if (!initialized) {
[Settings setDefaults];
initialized = YES;
}
return [NSUserDefaults standardUserDefaults];
}
+ (void) registerForChange:(id)observer selector:(SEL)method
{
[[NSNotificationCenter defaultCenter] addObserver:observer selector:method name:NSUserDefaultsDidChangeNotification object:nil];
}
+ (void) unregisterForChange:(id)observer
{
[[NSNotificationCenter defaultCenter] removeObserver:observer name:NSUserDefaultsDidChangeNotification object:nil];
}
Related
I am trying to access the nsstring data out side the function and also outside the class.
How can I access useridStr outside the function and class? This is my code:
-(id)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSString *loginStatus = [[NSString alloc] initWithBytes:[webData mutableBytes]
length:[webData length] encoding:NSUTF8StringEncoding];
NSDictionary *loginDict = [[loginStatus JSONValue] objectForKey:#"UserDetails"];
NSArray *userId = [loginDict valueForKey: #"userid"];
NSString *useridStr = [userId lastObject];
NSLog(#"--------------....%#", useridStr);
}
NSUserDefaults *pre = [NSUserDefaults standardUserDefaults];
[pre setObject:useridStr forKey:#"useridStr"];
where you want to need string:
NSUserDefaults *pre =[NSUserDefaults standardUserDefaults];
NSString * useridStr =[pre stringForKey:#"useridStr"];
OR
In .h file of anotherView
-(id)initUserInfo:(NSString *)string;
In .m file of anotherView
-(id)initUserInfo:(NSString *)string{
if (self = [super initWithNibName:#"nextView" bundle:nil]) {
useridStr=string
}
return self;
}
In .m File of firstView
-(IBAction)btnNext_TouchUpInside:(id)sender{
nextView *second =[[nextView alloc]initUserInfo:useridStr];
[self presentModalViewController:second animated:NO];
}
What Piyush suggested is also correct. But there is also another way to achieve it.
As he suggested NSUserDefaults to save data you should keep in mind that NSUserDefaults is generally used to save data like preferences which you want it to be stored even after Application is closed by user and you want those data again when you start your application.
So if you want to save data like preferences go for NSUserDefaults. If you want your data to be available throughout your application while its running and you do not need to save them like preferences I would recommend you declare that object globally in Appdelegate file and access them whenever you need. You should not store them as NSUserDefaults because as Apple document says whatever you store in NSUserDefaults it will be saved in user's default database. So that will consume memory of your device. So in short saving everything to NSUserDefaults won't be a good idea if we consider memory managent concepts.
Please help! I'm a newbie to programming and I'm having the following trouble. I am trying to write my first iphone app and I would like it to do the following.
When the app launches user enters name, presses button and goes to new view. Their name is saved to file and used through out the app. That much I have managed.
I would like the app to check to see if there is a saved file when it is launched and go directly to second view instead of the first view. I'm have search for days looking for an answer and I'm still not sure how to do this.
At the risk of seeming stupid do I use an IF statement and how do I write it. Please help.
Thanking you in advance.
You have to use NSUserDefaults for storing the user name and pass words. If you want to store more data's, have to use plist(Documents Directory) or core data or SQLite.
// Store the data
[[NSUserDefaults standardUserDefaults] setObject:#"yourPasswordString" forKey:#"YourKey"];
// Retrieve the data
NSString *passWord = [[NSUserDefaults standardUserDefaults] objectForKey:#"YourKey"];
Once you retrieved the data, you have to check the conditions like,
if(passWord == nil)
{
//load first view
}
else
{
// load second view
}
Thanks!
if you're using NSUserDefaults to save it then all you have to do is try reading the value into a string, then check if it is nil, if it is, then the files isn't there and you would load your first view, if it was, then load your second view.
NSString *tempStr = [[NSUserDefaults standardUserDefaults] objectForKey:#"yourKey"];
if(tempStr == nil)
{
//load your first view
}
else
{
// load your second view
}
You need to read your key back out in order to test if it is nil, the way you are doing this, you will never be nil and will always use the else choice, you need to set your object elsewhere, probably in the if statement.
-(IBAction)LogInButton:(id)sender
{
NSString *tempStr = [[NSUserDefaults standardUserDefaults] objectForKey:#"UserName"];
if (tempStr == nil || [tempStr isEqualToString:""])
{
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[prefs setObject:Name.text forKey:#"UserName"];
[prefs synchronize];
ClubSearchViewController *CSearch = [[ClubSearchViewController alloc]initWithNibName:#"ClubSearchViewController" bundle:Nil];
[self presentModalViewController:CSearch animated:YES];
}
else
{
SearchMenu *SMenu = [[SearchMenu alloc]initWithNibName:#"SearchMenu" bundle:nil];
[self presentModalViewController:SMenu animated:YES];
}
}
-(IBAction)LogOutButton:(id)sender
{
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[prefs setObject:#"" forKey:#"UserName"];
[prefs synchronize];
}
I have NSUserDefaults storing a number of string variables for things like name, date of birth, address, etc. What I would like to know is how to write a code that will create a new object for each new user. For example, I have a spinning wheel that shows up immediately after the first time the user runs the app. What I want, is for that wheel to have one single option - "New User". Once that New User fills out a bunch of text fields that I am using NSUserDefaults to save, I want that user to be saved on that spinning wheel so that the next time they open up the app they have the option of returning to all of the variables that they previously put in, or creating a new user so they can input all new variables.
I know how to do everything except write the code to create new users automatically. Potentially, the program should allow for a limitless number of these user objects and then just use something arbitrary like their last name to input into the spinning wheel. I would assume that the code would need to be put somewhere in the following code used to save the NSUserDefaults:
NSUserDefaults *userData = [NSUserDefaults standardUserDefaults];
[userData setObject:txtName.text forKey:#"name"];
---EDIT FOR CLARIFICATION ----
I am able to put multiple strings into this 'userData' object already by simply adding more lines like the 2nd line from above. What I want to know is how to add 'user2Data', 'user3Data', 'user4Data', 'usernData'..........to make a potentially limitless amount of user objects to store these variables?
You can add NSArray objects to NSUserDefaults.
NSUserDefaults *userData = [NSUserDefaults standardUserDefaults];
NSMutableArray *users = [NSMutableArray mutableArrayWithArray:[userData objectForKey:#"users"];
[users addObject:txtName.text];
[userData setObject:[NSArray arrayWithArray:users] forKey:#"name"];
[userData setObject:txtName.text forKey:#"name"];
If you need more than a single string for user data, you can look at using an NSDictionary object.
All that said, if you're going to be storing a lot of data, you should look at maybe saving .plist files in your app's Library directory.
You could modify the following to meet your needs, to be put into your app delegate:
+ (void) initialize
{
if ([self class] == [MyAppDelegate class]) {
// initialize user defaults dictionary
BOOL isFirstTimeRun = YES;
...
NSMutableDictionary *resourceDict = [NSMutableDictionary dictionary];
[resourceDict setObject:[NSNumber numberWithBool:isFirstTimeRun] forKey:kIsFirstTimeRunKey];
...
[[NSUserDefaults standardUserDefaults] registerDefaults:resourceDict];
}
}
...
- (void) applicationDidFinishLaunching:(UIApplication *)application
{
if ([[[NSUserDefaults standardUserDefaults] objectForKey:kIsFirstTimeRunKey] boolValue]) {
// you could do first-time-run stuff here, such as initializing
// other data model elements...
}
...
}
...
- (void) applicationWillTerminate:(UIApplication *)application
{
// if we're quitting the app, it must have been run at least once
if ([[[NSUserDefaults standardUserDefaults] objectForKey:kIsFirstTimeRunKey] boolValue])
[[NSUserDefaults standardUserDefaults] setObject:[NSNumber numberWithBool:NO] forKey:kIsFirstTimeRunKey];
...
}
What you probably want to do is create a property list for each user, and save the list of users in your NSUserDefaults. Once a user has been selected, you can then load the contents of the property list for that specific user and load/store all data in that particular property list. The basics of this approach is to use an NSDictionary* wherever you need to read from the property list and an NSMutableDictionary* whenever you need to both read and write to it. When you first construct the property list, you simply instantiate an NSMutableDictionary. When you want to save it or load it, you can use the NSPropertyListSerialization class in order to save or load the dictionary from/to a property list.
How can I make my application display something only when they first launch the application for the first time. Example: They open up my app, an alert comes up, saying something like, "Do you want to play the tutorial?" Then, if they close the app, then re-open it, it won't show up again.
Thanks
I'd recommend using NSUserDefaults:
- (void)openOneTime
{
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
static const NSString* kKey = #"One Time Key";
NSObject* keyValue = [defaults objectForKey:kKey];
if (keyValue == nil)
{
[self doMyOneTimeThing]; // pop a dialog, etc...
}
// Adds an object for our key which will get found the next time around,
// bypassing the above code block. The type and value of the object is
// not important; what matters more is that an object exists for that
// key at all.
[defaults setBool:YES forKey:kKey];
}
More tips on storing data persistently:
Method 1: Use the global user preferences system. You can do this, but it might be considered slightly hacky because it is designed to store user preferences, and I think this is a gray area, since the user doesn't have explicit control here. In any case, check out the docs for NSUserDefaults to find out how to do that.
Method 2: Write to a file whose existence indicates whether or not the tutorial has been viewed. You can easily create a file with an NSData object by calling its writeToFile:atomically: method. Later, you can use the NSFileManager class to check if that file exists or not.
Sample code:
- (NSString*) filename {
NSArray* paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory,
NSUserDomainMask, YES);
NSString* documentsDirectory = [paths objectAtIndex:0];
return [documentsDirectory stringByAppendingPathComponent:#"notFirstTime"];
}
- (void) setNotFirstTime {
NSData* data = [[[NSData alloc] init] autorelease];
[data writeToFile:[self filename] atomically:YES];
}
- (BOOL) isNotFirstTime {
return [[NSFileManager defaultManager] fileExistsAtPath:[self filename]];
}
You could store in your property store a boolean value saying whether it's the first time or not, then check that on application start.
I want to check if my iPhone app is running for the first time. I can create a file in the documents folder and check that file to see if this is the first time the app is running, but I wanted to know if there is a better way to do this.
I like to use NSUserDefaults to store an indication of the the first run.
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if (![defaults objectForKey:#"firstRun"])
[defaults setObject:[NSDate date] forKey:#"firstRun"];
[[NSUserDefaults standardUserDefaults] synchronize];
You can then test for it later...
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if([defaults objectForKey:#"firstRun"])
{
// do something or not...
}
Ok what confuses the hell out of me about User Defaults.
WHERE are they stored?
you dont care it varies per iOS/Mac.
you just getVALUE by KEY
setVALUE by KEY + synchronize
iOS/Mac does the rest.
This is the common use case:
Checking for the existence of a value e.g firstRun.
The first time it will NOT EXIST so usually followed by setting the value.
2nd Run
- on next loop it does exist and other use case/else stmt is triggered
---- .h
#interface MyAppDelegate : UIResponder <UIApplicationDelegate>
//flag to denote if this is first time the app is run
#property(nonatomic) BOOL firstRun;
------ .m
#implementation MyAppDelegate
#synthesize firstRun = _firstRun;
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
//==============
//Check to see if this is first time app is run by checking flag we set in the defaults
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
if (![defaults objectForKey:#"firstRun"]){
//flag doesnt exist then this IS the first run
self.firstRun = TRUE;
//store the flag so it exists the next time the app starts
[defaults setObject:[NSDate date] forKey:#"firstRun"];
}else{
//flag does exist so this ISNT the first run
self.firstRun = FALSE;
}
//call synchronize to save default - where its saved is managed by iOS - varies by device and iOS/Mac
[[NSUserDefaults standardUserDefaults] synchronize];
//TO TEST: delete the app on the device/simulator
//run it - should be the first run
//close it - make sure you kill it and its not just in the background else didFinishLaunchingWithOptions wont be called
//just applicationDidBecomeActive
//2nd run it should self.firstRun = FALSE;
//=============
//NOTE IMPORTANT IF YOURE ROOTVIEWCONTROLLER checks appDelegate.firstRun then make sure you do the check above BEFORE setting self.window.rootViewController here
self.window.rootViewController = self.navController;
[self.window makeKeyAndVisible];
return YES;
}
---- USING THE FLAG
MyAppDelegate *appDelegate = (MyAppDelegate *)[[UIApplication sharedApplication] delegate];
if (appDelegate.firstRun){
NSLog(#"IS FIRST RUN - Do something: e.g. set up password");
}else {
NSLog(#"FPMyMusicScreenViewController: IS NOT FIRST RUN - Prompt for password");
}
The examples above confused me a bit as they show how to check for it the first time but then mention how to 'check for it later' in the same comment.
The problem is when we find it doesnt exist we immediately create it and synchronize.
So checking for it late actually mean when you RESTART THE APP not in same run as first run.
In your app delegate register a default value:
NSDictionary *defaultsDict =
[[NSDictionary alloc] initWithObjectsAndKeys:[NSNumber numberWithBool:YES], #"FirstLaunch", nil];
[[NSUserDefaults standardUserDefaults] registerDefaults:defaultsDict];
[defaultsDict release];
Then where you want to check it:
NSUserDefaults *sharedDefaults = [NSUserDefaults standardUserDefaults];
if ([sharedDefaults boolForKey:#"FirstLaunch"]) {
//Do the stuff you want to do on first launch
[sharedDefaults setBool:NO forKey:#"FirstLaunch"];
[sharedDefaults synchronize];
}
You can implement it with the static method below. I think it's better since you can call this method as many times as you like, unlike the other solutions. enjoy: (Keep in mind that it's not thread-safe)
+ (BOOL)isFirstTime{
static BOOL flag=NO;
static BOOL result;
if(!flag){
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"hasLaunchedOnce"])
{
result=NO;
} else
{
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:#"hasLaunchedOnce"];
[[NSUserDefaults standardUserDefaults] synchronize];
result=YES;
}
flag=YES;
}
return result;
}
You can use a custom category method isFirstLaunch with UIViewController+FirstLaunch.
- (BOOL)isFirstLaunch
{
if ([[NSUserDefaults standardUserDefaults] boolForKey:#"kFirstLaunch"]) {
return YES;
}
else {
[[NSUserDefaults standardUserDefaults] setBool:YES forKey:#"kFirstLaunch"];
[[NSUserDefaults standardUserDefaults] synchronize];
return NO;
}
}
And when you need to use it in controller
BOOL launched = [self isFirstLaunch];
if (launched) {
//if launched
}
else {
//if not launched
}
Use NSUserDefaults. If the sharedDefault has a key for your app, its run before. Of course, you'll have to have the app create at least one default entry the first time the app runs.
Swift:
var isFirstLaunch: Bool {
get {
if (NSUserDefaults.standardUserDefaults().objectForKey("firstLaunchDate") == nil) {
NSUserDefaults.standardUserDefaults().setObject(NSDate(), forKey: "firstLaunchDate")
NSUserDefaults.standardUserDefaults().synchronize()
return true
}
return false
}
}
Another tip:
When using NSUserDefaults, these settings will be wiped if the app is ever deleted. If for some reason you require these settings to still hang around, you can store them in the Keychain.