来自NSDictionary PList的iPhone对象

Question

in my app I have a section where I load from a saved plist which has 2 nested dictionaries like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
    <key>1</key>
    <dict>
        <key>color</key>
        <string>yellow</string>
        <key>lang</key>
        <string>US</string>
        <key>name</key>
        <string>Peter</string>
        <key>uid</key>
        <string>1</string>
    </dict>
    <key>2</key>
    <dict>
        <key>color</key>
        <string>blue</string>
        <key>lang</key>
        <string>US</string>
        <key>name</key>
        <string>Josh</string>
        <key>uid</key>
        <string>2</string>
    </dict>
    <key>3</key>
    <dict>
        <key>color</key>
        <string>red</string>
        <key>lang</key>
        <string>DE</string>
        <key>name</key>
        <string>Susan</string>
        <key>uid</key>
        <string>3</string>
    </dict>
</dict>
</plist>

Now I want to access string like outer dictionary from key 2, value for inner key color (blue) I tried make 2 loops, and it works for the outer dictionary but I can't access the inner

NSMutableDictionary *savedData = [NSMutableDictionary dictionaryWithContentsOfFile:path]; // This contains all data from plist

for (int x=0; x<[savedData count]; x++) {
    NSString *itemNumber = [NSString stringWithFormat:@"%d", x+1];

    //This prints out the correct inner dictionary
    NSLog(@"item#%@: %@",itemNumber,[savedData objectForKey:itemNumber]);


    for (NSDictionary *dict in [savedData objectForKey:itemNumber]) {
        //prints out color, lang, uid, but no key-value pairs 
        NSLog(@"dict: %@",dict);
    }
}

I'd like to know how to directly access key value pairs inside the inner dictionary, could anyone give me a kick in the right direction, please?

Answer 1

How about this:

NSString *blueColorString = [[savedData objectForKey:@"2"] objectForKey:@"color"];

The trick is to nest the method calls, the first one [savedData objectForKey:2] returns you the inner dictionary object on which you can call the method again. Hope this works as intended.

Best, Robin

Answer 2

NSLog(@"%@", [savedData valueForKeyPath:@"1.color"]);

黄色

Answer 3

Typically, you would use valueForKey: when your keys are strings:

// to get to "blue" string
NSLog(@"outer key '2', inner key 'color' = %@",[[savedData valueForKey:@"2"] valueForKey:@"color"]);

// all inner key / value pairs
for (NSString *key in savedData) {
    NSDictionary *innerDict = [savedData valueForKey:key];

    for (NSString *innerKey in innerDict) {
        NSLog(@"key %@ value %@",innerKey,[innerDict valueForKey:innerKey]);
    }
}