objective-c - 异常解析 NSDictionary 内的 NSDictionary

Question

我有以下 plist:

<?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_NARR</key>
    <dict>
        <key>audio</key>
        <string>1 NARR AUDIO LOCATION</string>
        <key>text</key>
        <string>1 NARR TEXT</string>
    </dict>
    <key>1_C1_1</key>
    <dict>
        <key>text</key>
        <string>1 C1 1 TEXT</string>
        <key>audio</key>
        <string>1 C1 1 AUDIO LOCATION</string>
        <key>position</key>
        <string>1 C1 1 Position</string>
        <key>frameX</key>
        <string>1 C1 1 FRAMEX</string>
    </dict>
</dict>
</plist>

这是我遍历列表的代码:

NSDictionary *mainDictionary = [NSDictionary dictionaryWithContentsOfFile:[[NSBundle mainBundle] pathForResource:@"dialogues" ofType:@"plist"]];

    if (mainDictionary != nil){
        NSLog(@"viewDidLoad: mainDictionary != nil");
        [self parseDictionary:mainDictionary];
    }

- (void)parseDictionary:(NSDictionary*)aDictionary
{
    // enumerate key/values, recursing as necessary
    [aDictionary enumerateKeysAndObjectsUsingBlock:^(id key, id value, BOOL *stop) {
        if ([value isKindOfClass: [NSDictionary class]]) {
            NSLog(@"parseDictionary: isKindOfClass: NSDictionary");
            [self parseDictionary: value];
        } else {
            //... parse value here ...
            NSLog(@"parseDictionary: else: ");
            if ([value valueForKey:@"text"]) 
            {            
                NSLog(@"parseDictionary: else: if: ");
                //NSLog(@"parseDictionary: if: valueForKey:text == %@", [value valueForKey:@"text"]);
            }
        }
    }];
}

我遇到以下异常:

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<__NSCFString 0x6899760> valueForUndefinedKey:]: this class is not key value coding-compliant for the key text.'

我想不通为什么？您是否发现逻辑有任何问题？感谢您的回复。

这是完整的堆栈跟踪:

Terminating app due to uncaught exception 'NSUnknownKeyException',
reason: '[<__NSCFString 0x6e7a780> valueForUndefinedKey:]: this class
is not key value coding-compliant for the key text.'
*** First throw call stack: (0x16c0022 0x14e0cd6 0x16bfee1 0x1e7efe 0x156831 0x155c99 0x28bf 0x16bf8f8 0x15e39ed 0x165bbd6 0x165b84d
0x165b795 0x27cb 0x287e 0x16bf8f8 0x15e39ed 0x165bbd6 0x165b84d
0x165b795 0x27cb 0x2a41 0x55fa1e 0x23f1 0x4964be 0x497274 0x4a6183
0x4a6c38 0x49a634 0x1be3ef5 0x1694195 0x15f8ff2 0x15f78da 0x15f6d84
0x15f6c9b 0x496c65 0x498626 0x201d 0x1f95) terminate called throwing
an exception

Answer 1

考虑 plist 的这一部分:

    <key>audio</key>
    <string>1 NARR AUDIO LOCATION</string>

在您的 block 中，key 将是字符串“audio”，value 将是字符串“1 NARR AUDIO LOCATION”。该值是一个字符串，而不是字典，因此我们在您的条件中命中了 else 子句。然后你这样做:

        if ([value valueForKey:@"text"]) 

但是，正如我们已经发现的，value 是一个字符串。您不能对字符串调用字典方法。