jQuery .getJSON返回JSON但无法通过result.key访问

Question

My call to the REST server using $.getJSON(url).done(function(data) {}); return this

[
   "{"   id":1,
   "medname":"Medication No. 1",
   "qty":"2",
   "pDay":"3",
   "beforeAfterMeal":null
}", "{
   "id":3,
   "medname":"Medication No. 2",
   "qty":"1",
   "pDay":"1",
   "beforeAfterMeal":null
}", "{
   "id":4,
   "medname":"Medication 3",
   "qty":"4",
   "pDay":"1",
   "beforeAfterMeal":null
}
]

from console.log in Chrome.

By using $.each() I can loop through 3 times (thus it knows there are 3 entries in the JSON array), but when I use data[1].id or data[1].medname or any key, it gives me undefined or null ?

My doubt is, does the returned JSON array correct? It is returned from json_encode() (PHP) so I assumed it is correct.

Also, I tried $.parseJSON() to no result.

Maybe I am looking at the wrong place? A pointer will be of immense help.

This is the raw return value from the server (after json_encode() ):

[
  "{\"id\":1,\"medname\":\"Medication No. 1\",\"qty\":\"2\",\"pDay\":\"3\",\"beforeAfterMeal\":null}",
  "{\"id\":3,\"medname\":\"Medication No. 2\",\"qty\":\"1\",\"pDay\":\"1\",\"beforeAfterMeal\":null}",
  "{\"id\":4,\"medname\":\"Medication 3\",\"qty\":\"4\",\"pDay\":\"1\",\"beforeAfterMeal\":null}"
]

Is the above correct? If not, it would be useful for me to know which part is actually wrong.

UPDATE

I think I am getting where I made the mistake.

Here is what happens in the server, for each of the entries, they are individually encoded using json_encode() , and added to an array. In the end, the array is again encoded with json_encode()

Here is the var_dump for the array, before I explicitly call json_encode(array);

array (size=3)
  0 => string '{"id":1,"medname":"Medication No. 1","qty":"2","pDay":"3","beforeAfterMeal":null}' (length=81)
  1 => string '{"id":3,"medname":"Medication No. 2","qty":"1","pDay":"1","beforeAfterMeal":null}' (length=81)
  2 => string '{"id":4,"medname":"Medication 3","qty":"4","pDay":"1","beforeAfterMeal":null}' (length=77)

Is this where the mistake is? Should I not encode each entries individually first? :/

Answer 1

Ok, to sum it up.

The error here is that you have ran json_encode on all of the elements in the array and then running json_encode again on the full array. You should only run it once, on the full array.

Wrong way

$arr[] = json_encode(array('name' => 'hank'));
$arr[] = json_encode(array('name' => 'jofryhs'));
echo json_encode($arr);

Result: ["{\\"name\\":\\"hank\\"}","{\\"name\\":\\"jofryhs\\"}"]

Correct way

$arr = array(
    array('name' => 'hank'),
    array('name' => 'jofryhs')
);
echo json_encode($arr);

Result: [{"name":"hank"},{"name":"jofryhs"}]

Answer 2

in php code use:

<?php
    $c = array(array("id"=>1,
       "medname"=>"Medication No. 1",
       "qty"=>"2",
       "pDay"=>"3",
       "beforeAfterMeal"=>null),
    array("id"=>3,                  
       "medname"=>"Medication No. 2",
       "qty"=>"1",
       "pDay"=>"1",
       "beforeAfterMeal"=>null));

    echo json_encode($c, JSON_FORCE_OBJECT);
?>

this is the correct json format

[
   {"id":1,
   "medname":"Medication No. 1",
   "qty":"2",
   "pDay":"3",
   "beforeAfterMeal":null
}, {
   "id":3,
   "medname":"Medication No. 2",
   "qty":"1",
   "pDay":"1",
   "beforeAfterMeal":null
}, {
   "id":4,
   "medname":"Medication 3",
   "qty":"4",
   "pDay":"1",
   "beforeAfterMeal":null
}
]

then you can use

$.getJSON(url).done(function(data) {
    alert(data[0].id);
});

jsfiddle http://jsfiddle.net/suhailvs0/v8eGg/

Answer 3

If you got the string value from the server you need to parse it to get the object:

$.getJSON(url).done(function(data) {
    var obj = JSON.parse(data);
    var obj1 = obj[0]; 
    // and so on
});