I want to add the archiving (NSCoding) protocol to my model class, and then i implement both methods encodeWithCoder:(NSCoder*)coder and initWithCoder:(NSCoder*)coder. MyModelClass has 2 instance variables (NSString and NSImage), so i use the encodeObject:(id)object forKey:(NSString*)string method to encode the object plus the value for particular key. But i keep got the error :
*** -encodeObject:forKey: only defined for abstract class. Define -[NSArchiver encodeObject:forKey:]!
here's my code for NSCoding methods :
- (id)initWithCoder:(NSCoder *)coder {
[super init];
mainPath = [[coder decodeObjectForKey:#"mainPath"] retain];
icon = [[coder decodeObjectForKey:#"icon"] retain];
return self;
}
- (void)encodeWithCoder:(NSCoder *)coder {
NSLog(#"encode with coder is called");
[coder encodeObject:mainPath forKey:#"mainPath"];
[coder encodeObject:icon forKey:#"icon"];
}
And this is how i call them at my controller class :
id object = [assetArray objectAtIndex: [[rows lastObject] intValue]];
if ([object isKindOfClass:[ItemAssetModel class]])
NSLog(#"object is correct");
else
return NO;
NSData *data = [NSArchiver archivedDataWithRootObject: object];
if i change the encodeObject:(id)obj forKey:(NSString*)str with encodeObject:(id)obj, the error is stops, but the result is, the archived data does not copy the instance variable value (cmiiw). Do i miss something on this?
thanks.
hebbian
Try using NSKeyedArchiver instead of NSArchiver.
Related
I'm trying to make an app with Objective C.
I'm trying to serialise an array existing out of objects and after wards deserialise it. Inside the object there are the methods
(id)initWithCoder:(NSCoder *)coder` and `encodeWithCoder:(NSCoder *)coder
But it seems the "rootObject" stays "nil" in the "loadDataFromDisk" -method
Here is my code :
#import "Alarm.h"
#implementation Alarm
#synthesize array = _array;
#synthesize time = _time;
#synthesize coder = _coder;
-(id)initWithCoder:(NSCoder *)coder
{
self = [super init];
if(self)
{
_array = [coder decodeObjectForKey:#"array"];
_time = [coder decodeObjectForKey:#"time"];
}
return self;
}
-(void)encodeWithCoder:(NSCoder *)coder
{
[coder encodeObject:self.array forKey:#"array"];
[coder encodeObject:self.time forKey:#"time"];
}
#end
My save and load methods :
-(void)saveDataToDisk
{
NSString * path = [self pathForDataFile];
NSLog(#"Writing alarms to '%#' %lu", path, (unsigned long)array.count);
NSMutableDictionary * rootObject;
rootObject = [NSMutableDictionary dictionary];
[rootObject setValue:array forKey:#"alarms"];
[NSKeyedArchiver archiveRootObject:rootObject toFile:path];
}
-(void)loadDataFromDisk
{
NSString *path = [self pathForDataFile];
NSDictionary *rootObject = [NSMutableDictionary dictionary];
rootObject = [NSKeyedUnarchiver unarchiveObjectWithFile:path];
// "array" is an array with Objects of "Alarm"
array = [rootObject valueForKey:#"alarms"];
NSLog(#"Loaded from : %# %lu",path ,(unsigned long)array.count);
}
I hope anyone can help me out with this.
Thanks in advance.
You #synthized the array backing store (ivar) as _array. So you need to access the array as either _array or self.array. In saveDataToDisk and loadDataFromDisk it is accessed as array.
To test your array coding try something simple like this:
NSLog(#"array: %#", self.array);
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:self.array];
NSLog(#"data: %#", data);
NSArray *recovered = [NSKeyedUnarchiver unarchiveObjectWithData:data];
NSLog(#"recovered: %#", recovered);
Note: There is no need to wrap your array in a NSMutableDictionary.
When that works change it to the file based method calls.
Check that the filePath is valid.
Check that the file is created.
Check that the file contents are the same as in the above test code.
Note: There is no reason to wrap your array in a NSMutableDictionary.
I have a Mutable Array containing different objects such as strings, UIImage , etc.
They are sorted like this:
Example:
BugData *bug1 = [[BugData alloc]initWithTitle:#"Spider" rank:#"123" thumbImage:[UIImage imageNamed:#"1.jpeg"]];
...
...
NSMutableArray *bugs = [NSMutableArray arrayWithObjects:bug1,bug2,bug3,bug4, nil];
So basically it's an array with objects with different properties.
I Tried to save a single string to a file with the next code and it's working fine but when I try to save the array with the objects, i get an empty plist file.
NSString *docsDir = [NSHomeDirectory() stringByAppendingPathComponent:#"Documents"];
NSString * path = [docsDir stringByAppendingPathComponent:#"data.plist"];
NSLog(#"%#",bugs); //Making sure the array is full
[bugs writeToFile:path atomically:YES];
What am I doing wrong?
When you write a string or any primitive data to plist it can be saved directly. But when you try to save an object, you need to use NSCoding.
You have to implement two methods encodeWithCoder: to write and initWithCoder: to read it back in your BugData Class.
EDIT:
Something like this :
Change Float to Integer or String or Array as per your requirement and give a suitable key to them.
- (void)encodeWithCoder:(NSCoder *)coder {
[coder encodeObject:_title forKey:#"title"];
[coder encodeFloat:_rating forKey:#"rating"];
NSData *image = UIImagePNGRepresentation(_thumbImage);
[coder encodeObject:(image) forKey:#"thumbImage"];
}
- (id)initWithCoder:(NSCoder *)coder {
_title = [coder decodeObjectForKey:#"title"];
_rating = [coder decodeFloatForKey:#"rating"];
NSData *image = [coder decodeObjectForKey:#"thumbImage"];
_thumbImage = [UIImage imageWithData:image];
return self;
}
Even this will help you.
Implement NSCoding in your BugData class as below
- (void)encodeWithCoder:(NSCoder *)coder {
[coder encodeFloat:title forKey:#"title"];
[coder encodeFloat:rank forKey:#"rank"];
[coder encodeObject:UIImagePNGRepresentation(thumbImage) forKey:#"thumbImageData"];
}
- (id)initWithCoder:(NSCoder *)coder {
title = [coder decodeFloatForKey:#"title"];
rank = [coder decodeFloatForKey:#"rank"];
NSData *imgData = [coder decodeObjectForKey:#"thumbImageData"];
thumbImage = [UIImage imageWithData:imgData ];
return self;
}
BugData must implement the NSCoding protocol.You need this method to encode the data:
- (void) encodeWithCoder: (NSCoder*) encoder;
Where you should provide a NSData object representing the class (decode it with the decoder).
To read the plist you need to implement this method:
-(id) initWithCoder: (NSCoder*) decoder;
Where you read data from decoder and return a BugData object.
I'm writing a Cookbook application, and I've not been able to find anything on how to save the data of a class I've created (the Recipe class). The only way I've seen would be to possibly save the contents of this class as a whole without individually saving every element of the class for each object by making this method for my Recipe class:
-(void) writeToFile:(NSString *)file atomically:(BOOL)atomic{
}
But I have absolutely no idea how I'd go about implementing this to save this object to a file using this method. Some of the properties are:
NSString* name;
UIImage* recipePicture;
NSDate* dateAdded;
NSMutableArray* ingredients; //The contents are all NSStrings.
Does anyone know how to go about saving an object of the Recipe class?
It's been driving me crazy not being able to figure it out. Any help would be greatly appreciated. I already have a .plist entitled "RecipeData.plist".
Would I just need to write every property to the plist and initialize a new object of recipe with those properties at run time?
Adopt:
#interface Recipe : NSObject<NSCoding>
Implement:
- (void)encodeWithCoder:(NSCoder *)coder
{
[coder encodeObject:name_ forKey:#"name"];
[coder encodeObject:recipePicture_ forKey:#"recipePicture"];
[coder encodeObject:dateAdded_ forKey:#"dateAdded"];
[coder encodeObject:ingredients_ forKey:#"ingredients"];
}
// Decode an object from an archive
- (id)initWithCoder:(NSCoder *)coder
{
self = [super init];
if (self!=NULL)
{
name_ = [coder decodeObjectForKey:#"name"];
recipePicture_ = [coder decodeObjectForKey:#"recipePicture"];
dateAdded_ = [coder decodeObjectForKey:#"dateAdded"];
ingredients_ = [coder decodeObjectForKey:#"ingredients"];
}
return self;
}
Now in your save:
- (void) save:(NSString*)path recipe:(Recipe*)recipe
{
NSMutableData* data=[[NSMutableData alloc] init];
if (data)
{
NSKeyedArchiver* archiver=[[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
if (archiver)
{
[archiver encodeInt:1 forKey:#"Version"];
[archiver encodeObject:recipe forKey:#"Recipe"];
[archiver finishEncoding];
[data writeToFile:path atomically:YES];
}
}
}
And in the load:
- (Recipe*) load:(NSString*)path
{
Recipe* ret=NULL;
NSData* data=[NSData dataWithContentsOfFile:path];
if (data)
{
NSKeyedUnarchiver* unarchiver=[[NSKeyedUnarchiver alloc] initForReadingWithData:data];
if (unarchiver)
{
int version=[unarchiver decodeIntForKey:#"Version"];
if (version==1)
{
ret=(Recipe*)[unarchiver decodeObjectForKey:#"Recipe"];
}
[unarchiver finishDecoding];
}
}
return ret;
}
One option (besides encoding/decoding) is to store each attribute of your class in a dictionary. Then you write the dictionary to the file. The trick is to ensure that every object you put in the dictionary is allowed in a plist. Of the four properties you show, all but the UIImage can be stored as-is.
-(BOOL)writeToFile:(NSString *)file atomically:(BOOL)atomic{
NSMutableDictionary *data = [NSMutableDictionary dictionary];
[data setObject:name forKey:#"name"];
[data setObject:dateAdded forKey#"dataAdded"];
NSDate *imageData = UIImagePNGRepresentation(recipePicture);
[data setObject:imageData forKey:#"recipePicture"];
// add the rest
return [data writeToFile:file atomically:YES];
}
I updated this to return a BOOL. If it fails, it means one of two things:
The file was inappropriate
You tried to save a non-plist friendly object in the dictonary
You need to add code to avoid trying to add nil objects if you have any. The important thing is to ensure that all keys are strings and only plist-friendly objects are stored (NSString, NSNumber, NSDate, NSValue, NSData, NSArray, and NSDictionary).
I have an object that I convert into NSData using an NSKeyedArchiver and then store it into NSUserDefaults. Everything gets saved correctly except for the elements of an array that the object has. All the objects in the array have conform to the NSCoder protocols (or whatever theyre called- ex. self.property = [decoder decodeObjectForKey:#"key"] and [encoder encodeObjectForKey:#"key"])
When I save the object, the elements of the array remain in the array, but their properties themselves do not get saved. i DO call the sycnrhonize method, so that is not the issue.
NOTE that all other times i save & load it is correct, it just does not save the elements of an array that belongs to an object. Do i have to save that separately?
The "current status" NSNumber is not being saved. Objective and target are being saved
import "Level.h"
#implementation Level
#synthesize objective = _objective;
#synthesize isComplete = _isComplete;
#synthesize goldReward = _goldReward;
#synthesize xpReward = _xpReward;
#synthesize missionID = _missionID;
#synthesize currentStatus = _currentStatus;
#synthesize targetName = _targetName;
#synthesize owner = _owner;
-(void)dealloc{
[super dealloc];
}
-(id)initWithMissionID:(int)number{
if (self = [super init]) {
self.currentStatus = 0;
self.isComplete = NO;
self.missionID = [NSNumber numberWithInt:number];
[self setUpMisson];
}
return self;
}
-(void)setUpMisson{
if ([self.missionID intValue] == 0) {
self.xpReward = [NSNumber numberWithInt:100];
self.goldReward = [NSNumber numberWithInt:100];
self.objective = [NSNumber numberWithInt:3];
self.targetName = #"Swordsman";
CCLOG(#"Gotta kill some swordsmen!");
}
}
-(void)encodeWithCoder:(NSCoder *)encoder{
[encoder encodeObject:self.objective forKey:#"objective"];
[encoder encodeObject:self.isComplete forKey:#"isComplete"];
[encoder encodeObject:self.goldReward forKey:#"goldReward"];
[encoder encodeObject:self.xpReward forKey:#"xpReward"];
[encoder encodeObject:self.missionID forKey:#"missionID"];
[encoder encodeObject:self.currentStatus forKey:#"currentStatus"];
[encoder encodeObject:self.targetName forKey:#"targetName"];
[encoder encodeObject:self.owner forKey:#"owner"];
CCLOG(#"SAVING LEVEL");
}
-(id)initWithCoder:(NSCoder *)decoder{
if (self = [super init]) {
self.objective = [[decoder decodeObjectForKey:#"objective"]retain];
self.isComplete = [[decoder decodeObjectForKey:#"isComplete"]retain];
self.goldReward = [[decoder decodeObjectForKey:#"goldReward"]retain];
self.xpReward = [[decoder decodeObjectForKey:#"xpReward"]retain];
self.missionID = [[decoder decodeObjectForKey:#"missionID"]retain];
self.targetName = [[decoder decodeObjectForKey:#"targetName"]retain];
self.owner = [[decoder decodeObjectForKey:#"owner"]retain];
CCLOG(#"LOADING LEVEL");
}
return self;
}
-(void)updateStatusForKill:(AI *)killedTarget{
CCLOG(#"WE KILLED: %# and OUR GOAL IS: %#",killedTarget.name,self.targetName);
if ([killedTarget.name isEqualToString:self.targetName]) {
[self setCurrentStatus:[NSNumber numberWithInt:[self.currentStatus intValue]+1]];
CCLOG(#"Current Status: %i Objective: %i", [self.currentStatus intValue],[self.objective intValue]);
if ([self.currentStatus intValue] == [self.objective intValue]) {
[self completeMission];
}
}
}
-(void)completeMission{
[self.owner setCoins:[NSNumber numberWithInt:[[self.owner coins]intValue] + [self.goldReward intValue]]];
[self.owner setXp:[NSNumber numberWithInt:[[self.owner xp]intValue] + [self.xpReward intValue]]];
CCLOG(#"complete");
[[self.owner missionList]removeObject:self];
}
#end
EDIT: The "owner" refers back to the object being saved. I think this is where the problem is, so I'm removing that and testing again.
EDIT: and that did nothing!
What you describe should "just work." In the encodeWithCoder method of your custom object, you would just encode the array object, and that should cause the array and it's contents to be encoded.
However, if any of the objects in the array do not support NSCoding, that will fail. My guess is that something in your array (or it's children or grandchildren) does not support NSCoding.
I ran into this problem when trying to save an array of Accounts that contain property values and another custom object. I couldn't save my data with your proposed solution because I was arbitrarily adding accounts to an array, and it wouldn't make sense to come up with unique identifiers for dynamically added accounts. I ended up nesting the NSCoding protocol:
In my AccountManager class:
- (void) saveAllAccounts {
[self deleteAllAccounts]; //Just removes whatever was previously stored there
[[NSUserDefaults standardUserDefaults] setObject:[NSKeyedArchiver archivedDataWithRootObject:accountArray] forKey:saveAccountsArrayKey];
[[NSUserDefaults standardUserDefaults] synchronize];
}
In my Account class:
- (void) encodeWithCoder:(NSCoder *)aCoder {
[aCoder encodeObject:username forKey:#"username"];
[aCoder encodeObject:token forKey:#"token"];
[aCoder encodeObject:specialID forKey:#"special ID"];
NSData *data = [NSKeyedArchiver archivedDataWithRootObject:deviceArray];
[[NSUserDefaults standardUserDefaults] setObject:data forKey:#"device array"];
}
- (id) initWithCoder:(NSCoder *)aDecoder {
self = [super init];
if (self != nil) {
username = [[aDecoder decodeObjectForKey:#"username"] retain];
token = [[aDecoder decodeObjectForKey:#"token"] retain];
ecoID = [[aDecoder decodeObjectForKey:#"eco ID"] retain];
NSData *deviceArrayData = [[NSUserDefaults standardUserDefaults] objectForKey:#"device array"];
if (deviceArrayData != nil) {
NSArray *savedArray = [NSKeyedUnarchiver unarchiveObjectWithData: deviceArrayData];
if (savedArray != nil)
deviceArray = [[NSMutableArray alloc] initWithArray:savedArray];
}
}
return self;
}
In my AccountDevice class:
- (void) encodeWithCoder:(NSCoder *)aCoder {
[aCoder encodeObject:pairingPassword forKey:#"pairing password"];
[aCoder encodeObject:devicePin forKey:#"device pin"];
}
- (id) initWithCoder:(NSCoder *)aDecoder {
self = [super init];
if (self != nil) {
password = [[aDecoder decodeObjectForKey:#"password"] retain];
pin = [[aDecoder decodeObjectForKey:#"pin"] retain];
}
return self;
}
It might be a little buggy because I haven't finished testing it, but my preliminary tests were successful, and I think the concept is there.
It looks like you're using -encodeObject:forKey: and -decodeObjectForKey: even on values that aren't objects. For example, in your -initWithMissionID: you've got:
self.isComplete = NO;
which makes me think that complete is a BOOL property, but your -encodeObject:forKey: says:
[encoder encodeObject:self.isComplete forKey:#"isComplete"];
I think you probably want to call -encodeBool:forKey: instead, like this:
[encoder encodeBool:self.isComplete forKey:#"isComplete"];
On the other hand, I'd really expect some sort of warning if the problem were that simple. Do you get any warnings? It's harder to infer the types of your other properties, but look at each of your properties for the same kind of problem.
found a workaround using a Unique-Id system for each mission and saving the progress for each mission separately into NSUserDefaults which are just then loaded again. Not ideal, but it works. Thanks for everyone's help!
I have an array that I'm saving to NSUserDefaults, containing an array of my custom class Assignment, which conforms to the NSCoding protocol. The array saves and loads properly, and I can verify that the retrieved first object of the array is of the class Assignment. The problem happens when I try to access ivars of the Assignment object in the array. It crashes and I get the following error:
*** -[CFString respondsToSelector:]: message sent to deallocated instance 0x3948d60
Here is the code I'm using to save to user defaults. Note that I am also retrieving and checking the saved object for debugging purposes.
-(void)saveToUserDefaults:(NSArray*)myArray
{
NSUserDefaults *standardUserDefaults = [NSUserDefaults standardUserDefaults];
if (standardUserDefaults) {
[standardUserDefaults setObject:[NSKeyedArchiver archivedDataWithRootObject:myArray] forKey:#"Assignments"];
[standardUserDefaults synchronize];
}
NSLog(#"Assignments array saved. (%d assignments in array)",[myArray count]);
NSData *dataCheck = [[NSData alloc] initWithData:[standardUserDefaults objectForKey:#"Assignments"]];
NSArray *arrayCheck = [[NSArray alloc] initWithArray:[NSKeyedUnarchiver unarchiveObjectWithData:dataCheck]];
NSLog(#"Checking saved array (%d assignments in array)",[arrayCheck count]);
if ([[arrayCheck objectAtIndex:0] isKindOfClass:[Assignment class]]) {
NSLog(#"It's of the class Assignment.");
}
Assignment *testAssignment = [[Assignment alloc] initWithAssignment:[arrayCheck objectAtIndex:0]];
NSLog(#"Title: %# Course: %#",[testAssignment title],[testAssignment course]);
}
Everything is fine until I allocate testAssignment, which is where the crash happens. Does anyone have any ideas?
EDIT: Here are my NSCoding methods in the Assignment class:
- (void)encodeWithCoder:(NSCoder *)coder {
[coder encodeObject:title forKey:#"title"];
[coder encodeObject:course forKey:#"course"];
[coder encodeObject:dueDate forKey:#"dueDate"];
[coder encodeObject:notes forKey:#"notes"];
}
- (id)initWithCoder:(NSCoder *)coder {
self = [[Assignment alloc] init];
if (self != nil)
{
title = [coder decodeObjectForKey:#"title"];
course = [coder decodeObjectForKey:#"course"];
dueDate = [coder decodeObjectForKey:#"dueDate"];
notes = [coder decodeObjectForKey:#"notes"];
}
return self;
}
Answered my own question. In initWithCoder, I needed to retain all of the objects I was decoding:
//Example
title = [[coder decodeObjectForKey:#"title"] retain];
Everything works beautifully now. :)