在iphone应用程序中使用Json

我想在我的 iphone项目中使用Json,
但我没有得到如何在我的项目中开始使用json.

帮助我摆脱这种状况.
提前致谢.

好吧,如果你想要你可以开始这个

http://iosdevelopertips.com/networking/iphone-json-flickr-tutorial-part-1.html

本教程将帮助您了解json的功能,但是如果您想在代码中开始使用它,那么您应该使用以下示例:

April 26, 2009
Dealing with JSON on iPhone
You can easily use the JSON (JavaScript Object Notation) data format in client-server communications 
when writing an iPhone app. This blog is not suggesting that JSON is a more superior format for data 
exchange than its counterparts such as XML. In fact, we have many projects that don't use JSON.
However, handling JSON is relatively straight forward in ObjectiveC.
Unfortunately, Apple iPhone SDK (as of this writing, the latest is iPhone 2.2.1) doesn't come with 
a built-in JSON parser. But I found out a good one called json-framework. It is both a generator 
and a parser. As a generator, json-framework can create JSON data from an NSDictionary. As a parser, 
you can pass to json-framework an NSString that consists of JSON data and it will return a 
NSDictionary that encapsulates the parsed data.

Next, I'm going to show you several examples. Before you proceed, download the library and make 
sure you add it to your SDK path list (see INSTALL file that comes with it). If setup properly, 
you should be able to start using the library by importing its header file:

#import "JSON/JSON.h"

Consider the following code:

    NSDictionary *requestData = [NSDictionary dictionaryWithObjectsAndKeys:
                         @"grio", @"username",
                         @"hellogrio", @"password",
                          nil];

This instantiates a new dictionary which we'll turn into a JSON string. To do so, you'll need to 
use a function called JSONRepresentation. This function is added as a category to NSObject. It 
means that as long as there's an import of JSON.h file, you can call the function on any NSObject 
object.

    NSString* jsonString = [requestData JSONRepresentation];

And this is what you got when you print (NSLog(@"%@", jsonString);):

    {"username":"grio","password":"hellogrio"}

Parsing is just as simple. Consider the following JSON data:

{
    "menu": {
        "id": "file",
        "value": "File",
        "popup": {
            "menuitem": [
            {
                "value": "New",
                "onclick": "CreateNewDoc()"
            },
            {
                "value": "Open",
                "onclick": "OpenDoc()"
            },
            {
                "value": "Close",
                "onclick": "CloseDoc()"
            }
            ]
        }
    }
}

Assume that this is the data that you received from a web service called and is currently stored 
in an NSString called jsonResult. To parse it, you need to create SBJSON object and call one of 
its initialization method, objectWithString.

    SBJSON *json = [[SBJSON new] autorelease];
    NSError *jsonError;
    NSDictionary *parsedJSON = [json objectWithString:jsonResult error:&jsonError];

If parsing fails for reasons such as invalid construct of JSON format, jsonError variable will 
be filled with the error info. If it is successful, parsedJSON will contain keys whose values 
are either an NSString or NSDictionary. Let's look at the inside of parsedJSON:

    NSDictionary* menu = [parsedJSON objectForKey:@"menu"];
    NSLog(@"Menu id: %@", [menu objectForKey:@"id"]);
    NSLog(@"Menu value: %@", [menu objectForKey:@"value"]);

And here's the output:

    Menu id: file
    Menu value: File

Observe the JSON data again. popup is an NSDictionary which has an array of menuitem.

    NSDictionary* popup = [menu objectForKey:@"popup"];
    NSArray* menuItems = [popup objectForKey:@"menuitem"];
    NSEnumerator *enumerator = [menuItems objectEnumerator];
    NSDictionary* item;
    while (item = (NSDictionary*)[enumerator nextObject]) {
        NSLog(@"menuitem:value = %@", [item objectForKey:@"value"]);
    }

And this is the output:

    menuitem:value = New
    menuitem:value = Open
    menuitem:value = Close

对不起,我忘了这个网站的链接

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