PHP / IOS：为网络服务编码json的最佳方法是什么？

Question

I am trying to create a web service that serves up json from a mysql database through php for display in an iPhone app.

I have a standard mysql/php setup.

The data is in a table with fields and records. It is queried with sql to create a record set. Each record in the recordset is a row.

php

$sql = "SELECT userid,task,longtask FROM tasks WHERE userid = 1 LIMIT 1";
$res = mysql_query($sql) or die(mysql_error());  
$tasks = array();
while($row = mysql_fetch_assoc($res)) {
$tasks[] = array('row'=>$row);
 } 
echo json_encode(array('tasks'=>$tasks));
//

The web service produces the following output:

{"tasks":[{"row":{"userid":"1","task":"send email to Bob","longtask":"include attached memo"}}]}

However, I'm having a lot of trouble getting this to read into IOS suggesting that there might be a better format for the web service.

The structure is different from that in tutorials and other sources I have found for reading the json into IOS (none of which use php/mysql).

Can anyone tell me a better way to structure the json or alternatively code to read this json in iOS to grab the userid, task and other variables.

When I try this, I get an error that it cannot rad row at index:0

      NSError* error;
    NSDictionary* json = [NSJSONSerialization JSONObjectWithData:responseData //1
                                                         options:kNilOptions 
                                                           error:&error];
    NSLog(@"about to print json: %@",json);
NSMutableArray *getElement = [json objectForKey:@"tasks"];
    for (NSDictionary *dict in getElement) {
        NSArray *array = [dict objectForKey:@"row"];
        NSString *str = [array objectAtIndex:0];
    }

Thanks in advance for any suggestions.

Answer 1

Method 1: Edit PHP Code

Index 0 is not available because you are fetching an associative array from PHP using mysql_fetch_assoc .

Using mysql_fetch_array will return an array containing both zero-based indices and associative keys by default.

$sql = "SELECT userid,task,longtask FROM tasks WHERE userid = 1 LIMIT 1";
$res = mysql_query($sql) or die(mysql_error());  
$tasks = array();
while($row = mysql_fetch_array($res)) {
    $tasks[] = array('row'=>$row);
} 
echo json_encode(array('tasks'=>$tasks));

Will output

{"tasks":[{"row":{"0":"1","userid":"1","1":"send email to Bob","task":"send email to Bob","2":"include attached memo","longtask":"include attached memo"}}]}

Now you can retrieve the userid using either of the keys 0 or userid .

Method 2: Edit iOS Code

Edit iOS Code. But for this to work, you will have to know the keys in the row.

NSString *str = [array objectForKey:@"userid"];`