Android app to read JSON from website

Question

I'm trying to start off my Android app journey with an app to display information from a website. The website is from a power draft system that helps me monitor temperatures of the fire and pieces of meat that I'm cooking for long periods of time on my smoker.

The JSON page is found at http://192.168.101.101/stoker.json on my local network and the data looks like this:

{
"stoker": {
    "sensors": [
        {
            "id": "620000116F01CA30",
            "name": "SS2",
            "al": 0,
            "ta": 66,
            "th": 75,
            "tl": 65,
            "tc": 69.1,
            "blower": null
        },
        {
            "id": "E20000116F0CDB30",
            "name": "brskt2",
            "al": 0,
            "ta": 203,
            "th": 32,
            "tl": 32,
            "tc": 71.7,
            "blower": null
        }

The code that I'm trying to use kept failing, so I added a log to the first step of the process to see what was being found. Here is the code:

try {
    HttpClient httpclient = new DefaultHttpClient();
    HttpPost httppost = new HttpPost("http://192.168.101.101/stoker.json");
    HttpResponse response = httpclient.execute(httppost);
    HttpEntity entity = response.getEntity();
    InputStream webs = entity.getContent();

try {
    BufferedReader reader = new BufferedReader(new InputStreamReader(webs,"iso-8859-1"),4);
    StringBuilder sb = new StringBuilder();
    String line = null;
    while ((line = reader.readLine()) != null) {
        sb.append(line + "\n");
    }

    webs.close();

    result=sb.toString();
    Log.i("log_tag", result);

Here is the result from log during debug:

09-10 08:44:58.375: I/log_tag(748): <body>
09-10 08:44:58.375: I/log_tag(748): <h1>415 Unsupported Type</h1>
09-10 08:44:58.375: I/log_tag(748): </body>

I thought that reading the JSON information would be pretty straightforward, but it obviously isn't. What am I missing here?

At this point I would just like to display the information on my phone and nothing more. Down the road I would like to add more features to the app such as posting changes back to the JSON site and local alarms, but not right now.

stoker.json is a static file? And not generated from PHP or any framework/tool/etc? — RvdK, Sep 10 '12 at 14:32
i would recommend you to use gson from google. much simpler and better examples. — Mr.S, Sep 10 '12 at 14:35
check your server logs to see what causes it. it;s server problem. result string is not valid json string — Vjy, Sep 10 '12 at 14:35

score 1 · Accepted Answer · answered Sep 10 '12 at 14:37

1

It looks like a server-side error. What you can try is to change your HttpPost request to a HttpGet one.

If this doesn't work, then maybe your server is waiting for some specific data in the request header (Sometimes, the server wait for a specific User-agent field, or langage...)

Can you show us the server-side code which is generating this JSON ?

answered Sep 10 '12 at 14:37

Orabîg

11,718
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Thanks for the HttpGet change, that worked. The log shows the correct information being read and now I have an error in the next section of the code where the JSON is being parsed. I'm going to work on that and see if I can't tackle it myself. If not, I know I can get some great answers from the folks on here. – aubreyfreemaniii Sep 10 '12 at 14:46

score 1 · Answer 2 · answered Sep 10 '12 at 14:44

HTTP Status 415 - Unsupported Media Type in your case indicates that the server does not support the requested method for the requested resource, because you are trying to use the HTTP POST method instead of GET.

The full definition from the specification is:

The server is refusing to service the request because the entity of the request is in a format not supported by the requested resource for the requested method

So I think you should be using HTTPGet instead. That said, you should really try to use a library that supports binding of JSON objects to Java classes. There are many libraries that encapsulate this functionality which should make your code a lot less complex since you are relying on a (hopefully well-tested) library.

score 0 · Answer 3 · answered Sep 10 '12 at 14:42

0

try adding

httppost.setHeader("Accept", "application/json");
httppost.setHeader("Content-type", "application/json");

answered Sep 10 '12 at 14:42

Vinay W

9,912
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score 0 · Answer 4 · answered Sep 10 '12 at 14:52

It looks like... you are getting Wrong response from the server. so finally you have to check why is it so

One More thing You can do...please check Status Code from the response. You will get exact what mistake is being done by you or Server.

System.out.println(response.getStatusLine().getStatusCode());

and match your Response code from http://en.wikipedia.org/wiki/List_of_HTTP_status_codes

You will get exact .........whats wrong is going on...

Android app to read JSON from website

4 Answers4