Save NSNumber in plist, not working

Question

So I'm new to Obj-C (with experience in C and C++) and I've been trying stuff.
Quite simply, I want to save and load the score and level of the user as they progress.
I have 3 functions, getFilePath, loadData and savaData.

My getFilePath and loadData seem to work fine but I'm not able to get the saveData to work.

here is my code for it:

 -(void)saveData
 {
    NSNumber *updatedScore = [NSNumber numberWithInt:score];
    NSNumber *updatedLevel = [NSNumber numberWithInt:level];
    NSLog(@"The level im saving is %@",updatedLevel);
    NSLog(@"The score im saving is %@",updatedScore);
    NSMutableArray *value = [[NSMutableArray alloc]initWithObjects:updatedLevel,updatedScore, nil];
    [value writeToFile:[self getFilePath] atomically:YES];
}

-(NSString *)getFilePath
{
    NSArray *pathArray = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    NSLog(@"the path is %@",pathArray);
    return [[pathArray objectAtIndex:0]stringByAppendingPathComponent:@"saved.plist"];
}

My NSLog messages return the right values and the user progresses levels,but I'm not able to save them.

Answer 1

The issue is that the getFilePath method is using NSDocumentationDirectory rather than NSDocumentDirectory. Unfortunately, Xcode's auto-complete logic makes it all too easy to pick the wrong one.

---

Two further suggestions:

1. You should probably be checking the result of writeTofile, perhaps something like:

   NSArray *array1 = @[@1, @5, @3.423];
   BOOL success = [array1 writeToFile:path atomically:YES];
   NSAssert(success, @"%s: write failed", __FUNCTION__);
   

2. Personally, since I often use this pattern for creating a string that references the path of a file in the NSDocumentDirectory directory, I created a code snippet for it which eliminates the opportunity for me to mistype this. It gives me "auto complete" for several lines of code. So, suppose I have the following two lines in my code:

   NSString *documentsPath = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES)[0];
   NSString *path          = [documentsPath stringByAppendingString:<#filename#>];
   

   Clearly, use whatever code you want, but the key is to use <#filename#> placeholder for the parameter to stringByAppendingString. Then, as described in the Creating a Custom Code Snippet documentation (or see NSHipster's discussion on the topic), you can drag these two lines of code to the snippet library give it a good name (and just as importantly, a good shortcut, I use "documentsPath" for my shortcut). Now, in the future, I can just start typing "documentsPath" in my code, and I'll be prompted with these two lines of code.

   Since I've started using this particular code snippet, I've never made a mistake about accidentally grabbing the wrong value instead of NSDocumentDirectory.

Answer 2

The documentation for writeToFile:atomically: specifies that only the types NSString, NSData, NSArray, or NSDictionary can be written to file.

To write NSNumber data to a file look into alternative serialization methods like: NSKeyedArchiver, NSPropertyListSerialization or NSJSONSerialization