How do I get values from a tiered .plist? - ios

Question

I've already looked at Parse Plist (NSString) into NSDictionary and deemed it to be not a duplicate, as that question and its answer do not address my concerns.
I have a .plist file in the file system structured like this:
The source code of this .plist file looks like this:
{
"My App" = {
"Side Panel" = {
Items = {
Price = "#123ABC";
};
};
};
}
I know how to get an item in the Root like this:
[[NSBundle mainBundle] pathForResource:#"filename" ofType:#"plist"];
NSDictionary *dict = [NSDictionary dictionaryWithContentsOfFile:path];
NSString value = [dict objectForKey:#"key"]);
But what if the structure is like mine, with tiered dictionaries? How do I get the value of Price?
I would like to do this all in one method, ideally like this:
Calling
NSString *hexString = [self getColorForKey:#"My App.Side Panel.Items.Price"];
Definition
- (NSString *) getColorForKey: (NSString *)key
{
NSArray *path = [key componentsSeparatedByString:#"."];
NSDictionary *colors = [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:#"Colors" ofType:#"plist"]];
NSString *color = #"#FFFFFF"; // white is our backup
// What do I put here to get the color?
return color;
}

Answer 1

Here's the solution that worked for me:
+ (NSString*) getHexColorForKey:(NSString*)key
{
NSArray *path = [key componentsSeparatedByString:#"."];
NSDictionary *colors = [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:#"Colors" ofType:#"plist"]];
NSString *color = #"#FFFFFF";
for (NSString *location in path) {
NSObject *subdict = colors[location];
if ([subdict isKindOfClass:[NSString class]])
{
color = (NSString*)subdict;
break;
}
else if ([subdict isKindOfClass:[NSDictionary class]])
{
colors = (NSDictionary*)subdict; // if it's a dictinoary, our color may be inside it
}
else
{
[SilverLog level:SilverLogLevelError message:#"Unexpected type of dictinoary entry: %#", [subdict class]];
return color;
}
}
return color;
}
where key is an NSString that matches /^[^.]+(\.[^.]+)*$/, meaning it looks like my targeted #"My App.Side Panel.Items.Price".

Answer 2

Yes I understand what you're looking to accomplish; thank you for the clarification. I will however add that the resources and advice I have written do provide the necessary information resolve your problem.
That said, the following gets your dictionary:
NSURL *plistURL = [[NSBundle mainBundle] URLForResource:#"Info" withExtension:#"plist"];
NSData *plistData = [NSData dataWithContentsOfURL:plistURL];
NSDictionary *tieredPlistData = [NSPropertyListSerialization propertyListWithData:plistData
options:kCFPropertyListImmutable
format:NULL
error:nil];
Then, if we're interested in the information contained in Items
NSDictionary *allItemsDictionary = tieredPlistData[#"My App"][#"Side Panel"][#"Items"];
Assuming that Items will contain a number of objects, you could use
NSArray *keys = [allItems allKeys];
for(NSString *key in keys){
NSString *colorValue = allItemsDictionary[key];
// do something with said color value and key
}
Or, if there is a single value you need, then just reference that key
NSString *colorForPriceText = allItemsDictionary[#"Price"];
But a few tips:
It's generally considered a better idea to keep frequently accessed values in code instead of a plist/file that is loaded at runtime.
That said, you wouldn't put your call to load from NSBundle in the same method you would use to query a specific value. In your example, every time you need a color, you end up re-accessing NSBundle and pile on unneeded memory allocations. One method would load the plist into an iVar NSDictionary and then that NSDictionary would be used separately by another method.