I have some data that's been stored using NSUserDefaults in one view and then being displayed in another view. The issue I'm having is that when the user changes the data and then returns to the view where the data is displayed (in a UILabel), the data that was first saved is displayed instead of the newer saved text.
I think I need to do something with viewDidAppear perhaps, so that every time the view appears the newest saved data is displayed.
here's the code that Im displaying the NSUserDefaults stored info on a UILabel:
NSString *aValue = [[NSUserDefaults standardUserDefaults] objectForKey:#"myTextFieldKey"];
NSLog(#"Value from standardUserDefaults: %#", aValue);
NSLog(#"Label: %#", myLabel);
myLabel.text = aValue;
if someone could point me in the right direction that would be great,
thanks
Put this text in
- (void) viewWillAppear:(BOOL)animated
{
[super viewWillAppear: animated];
NSString *aValue = [[NSUserDefaults standardUserDefaults] objectForKey:#"myTextFieldKey"];
NSLog(#"Value from standardUserDefaults: %#", aValue);
NSLog(#"Label: %#", myLabel);
myLabel.text = aValue;
}
And in your "edit" view in - viewWillDisappear: save changes in NSUserDefaults
When saving data to NSUserDefaults, it doesnt immediately write to the Persistent Storage. When you save data in NSUserDefaults, make sure you call:
[[NSUserDefaults standardUserDefaults] synchronize];
This way, the value(s) saved will immediately be written to Storage and each subsequent read from the UserDefaults will yield the updated value.
Do not forget the use synchronize when you set some value
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:YOUR_VALUE forKey:#"KEY_NAME"];
[defaults synchronize];
Now you can place your code in viewWillAppear method to retrieve the value from defaults, this will help you fetch the currentsaved value for your desired key.
NSUserDefaults* defaults = [NSUserDefaults standardUserDefaults];
NSString* strValue = [defaults objectForKey:#"KEY_NAME"];
myLabel.text = strValue != nil ? strValue : #"No Value";
Hope it helps
In Swift we can do it following way:
To save value:
let defaults = UserDefaults.standard
defaults.set(YOUR_VALUE, forKey: "YOUR_KEY_NAME")
To get value:
let defaults = UserDefaults.standard
let data = defaults.objectForKey("YOUR_KEY_NAME")
For more details visit:
https://www.hackingwithswift.com/example-code/system/how-to-save-user-settings-using-userdefaults
Related
So I have an app that lets you put in a title and an author on the front page, then you hit enter and it will go into the actual features of the app. I want to save the data with NSUserDefaults, so that when they click the enter button, it saves it *AND goes into the next view. I have it setup with the storybord already to go into the next view, but when I use this code:
-(IBAction)enter:(id)sender {
titleString = [[NSString alloc] initWithFormat:[title text]];
[title setText:titleString];
NSUserDefaults *titleDefault = [NSUserDefaults standardUserDefaults];
[titleDefault setObject:titleString forKey:#"stringkey"];
authorString = [[NSString alloc] initWithFormat:[author text]];
[title setText:authorString];
NSUserDefaults *authorDefault = [NSUserDefaults standardUserDefaults];
[authorDefault setObject:authorString forKey:#"stringkey2"];
}
It will always crash when you hit the button. I have all the NSStrings defined and such, so I don't see what the problem is. I also have it loading with:
title.text = [[NSUserDefaults standardUserDefaults] objectForKey:#"stringkey"];
author.text = [[NSUserDefaults standardUserDefaults] objectForKey:#"stringkey2"];
Under the viewdidload, so can I have some help as to why this wouldn't work?
Just to optimize your -enter:method:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:title.text forKey:#"stringkey"];
[defaults setObject:author.text forKey:#"stringkey2"];
[defaults synchronize]; // this will store them instantly!
For the crash: can you please provide us with the exact crash log? Maybe your Button is linked to an unknown selector...
First, there are a few questions about this: here, here. Try searching around first, and at least let people know why the duplicate questions you found didn't work for you.
Secondly, I think you might benefit from adding a synchronize. Use this:
titleString = [[NSString alloc] initWithFormat:[title text]];
[title setText:titleString];
NSUserDefaults *titleDefault = [NSUserDefaults standardUserDefaults];
[titleDefault setObject:titleString forKey:#"stringkey"];
[titleDefault synchronize];
authorString = [[NSString alloc] initWithFormat:[author text]];
[author setText:authorString];
NSUserDefaults *authorDefault = [NSUserDefaults standardUserDefaults];
[authorDefault setObject:authorString forKey:#"stringkey2"];
[authorDefault synchronize];
I also changed the [title setText:authorString]; line to [author setText:authorString];. I do, however, think it is a bit redundant the way you are allocating the NSStrings to the value of the text fields and then setting the text back to the value of the string you created. I don't get the need. Anyway, hope this helps.
I am making an app in which the user can select a song in a settings tab and have this played in a different view on demand. I want it so that this item can be stored if the user is to shut the app and reopen it another time.
I have managed to allow the user to select and store a song in with:
-(IBAction)showMediaPicker:(id)sender{
MPMediaPickerController *mediaPicker = [[MPMediaPickerController alloc] initWithMediaTypes: MPMediaTypeAny];
mediaPicker.delegate = self;
mediaPicker.allowsPickingMultipleItems = NO;
mediaPicker.prompt = #"Select Alarm Sound";
[self presentModalViewController:mediaPicker animated:YES];
}
- (void) mediaPicker: (MPMediaPickerController *) mediaPicker didPickMediaItems: (MPMediaItemCollection *) mediaItemCollection {
[self dismissModalViewControllerAnimated: YES];
settingsData.selectedSong = mediaItemCollection;//Object of type MPMediaItemCollection
but I want the user to have to do this every time they use the app.
I have tried using NSUserDefaults:
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:settingsData.selectedSong forKey:#"alarmSoundKey"];
[defaults synchronize];
but get the error:
* -[NSUserDefaults setObject:forKey:]: Attempt to insert non-property value '' of class 'MPMediaItemCollection'. Note that dictionaries and arrays in property lists must also contain only property values.
What are my options please? Not really sure how to tackle this one...
SOLUTION -
I can't answer my own questions yet so I'll put it up here:
I HAVE FOUND MY OWN SOLUTION TO THIS:
First convert/encode the MPMediaItemCollection to an NSData Object and slam store it using NSUserDefaults using:
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:mediaItemCollection];
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
[defaults setObject:data forKey:#"someKey"];
[defaults synchronize];
From there, you can decode and use anywhere else in your app....
NSUserDefaults *defaults = [NSUserDefaults standardUserDefaults];
NSData *data = [defaults objectForKey:#"someKey"];
MPMediaItemCollection *mediaItemCollection = [NSKeyedUnarchiver unarchiveObjectWithData:data]
Hope that is some help to someone. Spread the word, this hasn't been covered enough. Have literally been working on this problem for about 4 hours...
You can only store property list values in NSUserDefaults. Since MPMediaItemCollection conforms to NSCoding you could use an NSKeyedArchiver to store it instead.
http://developer.apple.com/library/ios/#documentation/Cocoa/Reference/Foundation/Classes/NSKeyedArchiver_Class/Reference/Reference.html#//apple_ref/doc/uid/TP40003672
You then use NSKeyedUnarchiver to read it back out of the file later.
You can also use the MPMediaItemPropertyPersistentID property. You can form a query to retrieve the item from the iPod library when your application next launches, and gracefully handle things like when the user decides to remove the song from their library.
I have two views.In One view when i click on custom button it goes into second view,In that i have text view and that data must store in temperary memory so i used following code:
NSString *myString=txtvNote.text;
[txtvNote setText:#""];
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
if (standardUserDefaults) {
[standardUserDefaults setObject:myString forKey:#"note"];
[standardUserDefaults synchronize];
}
and when i go back on 1st view by clicking on the add button it will save into database for that i used following code:
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
NSString *val = nil;
if (standardUserDefaults)
val = [standardUserDefaults objectForKey:#"note"];
NSLog(#"Note::%#",val);
and then pass this value in insert query.
Now my problem is when i left that value blank,it takes the value which is inserted before.
sequence must be like this
//first set text to something
[txtvNote setText:#""];
//then use that text
NSString *myString=txtvNote.text;
myString is a pointer to the text in txtvNote. So if you set that text to #"" then myString will be empty as well. To preserve the value of txtvNote at the time of assignment use copy or reset the text after saving it:
NSString *myString=[[txtvNote.text copy] autorelease];
[txtvNote setText:#""];
....
That's the way NSUserDefaults works - every value is stored in your app's preferences, and like any other collection in Obj-C, it doesn't take nil values. Use instance of NSNull class or empty string. Or even better - use intermediate controller to store values and use key-value observing in your first view.
I trying to save UILabel value to NSUserDefaults. I did IBAction with this code:
-(IBAction)saveData:(id)sender {
NSString *resultString = label.text;
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
[prefs setObject:resultString forKey:#"result"];
[prefs synchronize];
}
Then, I connect it to button with Touch Up Inside.
What log shows after I pressed the button:
result = 0;
When I pressed a second time, then it works.
result = "28.34";
What I'm doing wrong and how can I retrieve a result?
EDIT
With this code I display result in log. I put it to same action.
NSLog(#"%#", [[NSUserDefaults standardUserDefaults] dictionaryRepresentation]);
Your code looks correct, so the issue is probably not the function you posted but rather the code that contains your NSLog. You might be logging the value in a way that misses the first time it gets set.
Your log statement should be
NSLog(#"%#",[[NSUserDefaults
standardUserDefaults]
objectForKey:#"result"]);
This should be after you set the object in NSUserDefaults.
Add this to your applicationDidFinishLaunching in appDelegate or in init method in viewController(you have to create one) :
NSUserDefaults *prefs = [NSUserDefaults standardUserDefaults];
if(prefs == nil)
{
[prefs setObject:#"anything" forKey:#"result"];
[prefs synchronize];
}
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];
}