objectForKey 不返回任何内容

Question

-(NSMutableDictionary *)request:(NSString *)requestString {
    NSString *filepath = [[NSBundle mainBundle] pathForResource:requestString ofType:@"xml"];
    NSError *error = nil;
    respString = [NSString stringWithContentsOfFile:filepath usedEncoding:nil error:&error];
NSLog(@"Ping xml");
    tempDict = [[NSMutableDictionary alloc] initWithDictionary:[parser readXMLString:respString]];
    NSLog(@"%@",tempDict);
return tempDict;
}

直到那里，一切都好，NSLog 显示 tempDict 中有 2 个对象和键。 但是：

-(int) authenticateUser {
    NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] initWithDictionary:[self request:@"login"]];
    if ([[dictionary objectForKey:@"sessionId0"] isEqualToString:@"-1"] ) {
        //Some code
    }
    else {
        cError = 1;
        NSLog(@"%@",[dictionary objectForKey:@"sessionId0"]);
        appDelegate.sessionId = [dictionary objectForKey:@"sessionId0"];
    }
    [dictionary release];
    return cError;
}

在最后一个 else 处，cError 为 1，NSLog 对该对象输出 nil。 （整个字典的 NSLog 也输出 nil）

Answer 1

将此代码放入您的代码中，看看 dict 对象的输出是什么......

-(int) authenticateUser {
NSDictionary* dict = (NSDictionary *)[self request:@"login"];
NSLog(@"Dictionary %@",dict);    

NSMutableDictionary *dictionary = [[NSMutableDictionary alloc] initWithDictionary:[self request:@"login"]];
    if ([[dictionary objectForKey:@"sessionId0"] isEqualToString:@"-1"] ) {
        //Some code
    }
    else {
        cError = 1;
        NSLog(@"%@",[dictionary objectForKey:@"sessionId"]);
        appDelegate.sessionId = [dictionary objectForKey:@"sessionId"];
    }
    [dictionary release];
    return cError;
}