如何在android中存储json数据以便离线

Question

My application get JSON data from server. If I use my own json api , data is loaded only in internet connection. But if I use this api (https://pixabay.com/api/?key=5303976-fd6581ad4ac165d1b75cc15b3&q=kitten&image_type=photo&pretty=true), data is displayed also in offline, once application got internet connection.

The same code, one json url is loaded also after the loss of internet connectivity, another one's data doesn't display after internet disconnection. How to store data in android cache from server-side as this URL (https://pixabay.com/api/?key=5303976-fd6581ad4ac165d1b75cc15b3&q=kitten&image_type=photo&pretty=true).

My api (api1.php)

<?php 
    require("includes/connect.php");
header('Content-Type: application/json');

    $query="SELECT * FROM implink";
$result = $con->query('SELECT id,heading,content FROM implink');
$rows = $result->fetchAll(PDO::FETCH_ASSOC);
header('Content-Type: application/json;charset=utf-8');
echo json_encode(['info' => $rows],
        JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES | JSON_NUMERIC_CHECK);
?> 

Answer 1

My first suggestion is to not publish your API key. Pixabay may be free, but sharing API keys on the internet will put you infrastructure in danger.

Upon looking up the request it seems Pixabay is setting some headers that could affect your cache.

Access-Control-Max-Age → 86400
Cache-Control → max-age=86400
Content-Type → application/json

Check out the Android documentation on HttpResponseCache It outlines how you can force a cache response after setting up the HttpResponseCache.

     try {
         connection.addRequestProperty("Cache-Control", "only-if-cached");
         InputStream cached = connection.getInputStream();
         // the resource was cached! show it
     } catch (FileNotFoundException e) {
         // the resource was not cached
     }