Question

我是iOS开发新手，我正在尝试解析本地Json文件，例如

{"quizz":[{"id":"1","Q1":"When Mickey was born","R1":"1920","R2":"1965","R3":"1923","R4","1234","response","1920"},{"id":"1","Q1":"When start the cold war","R1":"1920","R2":"1965","R3":"1923","rep4","1234","reponse","1920"}]}

这是我的代码：

 NSString *filePath = [[NSBundle mainBundle] pathForResource:@"data" ofType:@"json"];
NSString *myJSON = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:NULL];
// Parse the string into JSON
NSDictionary *json = [myJSON JSONValue];

// Get all object
NSArray *items = [json valueForKeyPath:@"quizz"];

NSEnumerator *enumerator = [items objectEnumerator];
NSDictionary* item;
while (item = (NSDictionary*)[enumerator nextObject]) {
    NSLog(@"clientId = %@",  [item objectForKey:@"id"]);
    NSLog(@"clientName = %@",[item objectForKey:@"Q1"]);
    NSLog(@"job = %@",       [item objectForKey:@"Q2"]);
}

我在这个网站上找到了一个样本，但是我收到了以下错误

-JSONValue失败。错误是：在对象键之后不期望令牌'值分隔符'。

Answer 1

JSON具有严格的键/值表示法，R4和响应的键/值对不正确。试试这个：

NSString *jsonString = @"{\"quizz\":[{\"id\":\"1\",\"Q1\":\"When Mickey was born\",\"R1\":\"1920\",\"R2\":\"1965\",\"R3\":\"1923\",\"R4\":\"1234\",\"response\":\"1920\"}]}";

^{如果您从文件中读取字符串，则不需要所有斜杠}
你的文件是这样的：

{“quizz”：[{“id”：“1”，“Q1”：“当米奇是生 “ ”R1“： ”1920“， ”R2“： ”1965“， ”R3“： ”1923“， ”R4“： ”1234“， ”响应“： ”1920“}，{ ”ID“：” 1" ， “Q1”：“当开始感冒战”， “R 1”： “1920”， “R2”： “1965”， “R3”： “1923”， “R4”： “1234”， “效应初探”： “1920”}]}

我测试了这段代码：

NSString *jsonString = @"{\"quizz\":[{\"id\":\"1\",\"Q1\":\"When Mickey was born\",\"R1\":\"1920\",\"R2\":\"1965\",\"R3\":\"1923\",\"R4\":\"1234\",\"response\":\"1920\"}, {\"id\":\"1\",\"Q1\":\"When start the cold war\",\"R1\":\"1920\",\"R2\":\"1965\",\"R3\":\"1923\",\"R4\":\"1234\",\"reponse\":\"1920\"}]}";
NSLog(@"%@", jsonString);
NSError *error =  nil;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:[jsonString dataUsingEncoding:NSUTF8StringEncoding] options:kNilOptions error:&error];

NSArray *items = [json valueForKeyPath:@"quizz"];

NSEnumerator *enumerator = [items objectEnumerator];
NSDictionary* item;
while (item = (NSDictionary*)[enumerator nextObject]) {
    NSLog(@"clientId = %@",  [item objectForKey:@"id"]);
    NSLog(@"clientName = %@",[item objectForKey:@"Q1"]);
    NSLog(@"job = %@",       [item objectForKey:@"Q2"]);
}

我得到的印象是，您复制了旧代码，因为您没有使用Apple的序列化和枚举器而不是Fast Enumeration。整个枚举的东西可以简单地写成

NSArray *items = [json valueForKeyPath:@"quizz"];
for (NSDictionary *item in items) {
    NSLog(@"clientId = %@",  [item objectForKey:@"id"]);
    NSLog(@"clientName = %@",[item objectForKey:@"Q1"]);
    NSLog(@"job = %@",       [item objectForKey:@"Q2"]);
}

或者甚至是block based enumeration的爱好者，如果需要快速安全的枚举，你还有一个索引。

NSArray *items = [json valueForKeyPath:@"quizz"];
[items enumerateObjectsUsingBlock:^(NSDictionary *item , NSUInteger idx, BOOL *stop) {
    NSLog(@"clientId = %@",  [item objectForKey:@"id"]);
    NSLog(@"clientName = %@",[item objectForKey:@"Q1"]);
    NSLog(@"job = %@",       [item objectForKey:@"Q2"]);
}];

Answer 2

NSString *filePath = [[NSBundle mainBundle] pathForResource:@"fileName" ofType:@"json"];
NSString *myJSON = [[NSString alloc] initWithContentsOfFile:filePath encoding:NSUTF8StringEncoding error:NULL];
NSError *error =  nil;
NSArray *jsonDataArray = [NSJSONSerialization JSONObjectWithData:[myJSON dataUsingEncoding:NSUTF8StringEncoding] options:kNilOptions error:&error];

Answer 3

使用jsonlint.com查找JSON字符串中的错误在这种情况下，它表示您在"R4"附近有无效的JSON

Answer 4

json文件中似乎有拼写错误。

替换
"R4","1234","response","1920" "R4":"1234","response":"1920"的{{1}} 和
"rep4","1234","reponse","1920"与"rep4":"1234","response":"1920"

。{

Answer 5

Swift 2.3 我使用实用程序方法将JSON文件转换为Dictionary：

func getDictionaryFromJSON(jsonFileName: String) -> [String: AnyObject]? {
    guard let filepath = NSBundle.mainBundle().pathForResource(jsonFileName, ofType: "json") else {
        return nil
    }

    guard let data = NSData(contentsOfFile: filepath) else {
        return nil
    }

    do {
        let dict = try NSJSONSerialization.JSONObjectWithData(data, options: []) as? [String: AnyObject]
        return dict
    } catch {
        print(error)
        return nil
    }
}

Cocoa-Touch - 如何解析本地Json文件

5 个答案: