I am trying to build an android application that parses a JSON response from an api, I have included the API response below:
{
"success": 1,
"message": "Post Available!",
"posts": [
{
"post_id": "1",
"username": "foo",
"title": "my tile",
"message": "this is my message"
},
{
"post_id": "2",
"username": "user2",
"title": "titre 2",
"message": "this is my message 2"
},
{
"post_id": "3",
"username": "123",
"title": "12",
"message": "111"
},
]
}
This is the part of the code to read this JSON:
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("receiver", strSender));
JSONObject json = jsonParser.makeHttpRequest(
LOGIN_URL, "POST", params);
success = json.getInt(TAG_SUCCESS);
Log.d("ok", "ok");
if (success == 1){
messagesArray = (JSONArray)json.getJSONArray(TAG_POSTS);
for (int i= 0;i <messagesArray.length();i++){
Log.d("iteration", "iteration" + i);
JSONObject messageJson = messagesArray.getJSONObject(i);
Log.d("post_id","post_id: "+i+ " "+ messageJson.getString(TAG_POSTS_ID) );
Log.d("username","username: " +i+" " + messageJson.getString(TAG_POSTS_USERNAME));
Log.d("title", "title: " +i+ " " + messageJson.getString(TAG_POSTS_ID_TITLE));
Log.d("message","message: "+i+" "+ messageJson.getString(TAG_POSTS_ID_MESSAGE));
}
}else{
Log.d("failed", "!!!!!!!!!!!!!!!!!!!!!!!!");
}
Everything looks good, but when I try to run my app and fetch the data, the apps crash and exit with error No value for posts This is the logs from logcat:
09-27 23:15:37.119: W/System.err(489): org.json.JSONException: No value for posts
09-27 23:15:37.119: W/System.err(489): at org.json.JSONObject.get(JSONObject.java:354)
09-27 23:15:37.128: W/System.err(489): at org.json.JSONObject.getJSONArray(JSONObject.java:544)
09-27 23:15:37.128: W/System.err(489): at com.example.mysql.ReadMessages.onCreate(ReadMessages.java:73)
09-27 23:15:37.128: W/System.err(489): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
09-27 23:15:37.128: W/System.err(489): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
09-27 23:15:37.128: W/System.err(489): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
09-27 23:15:37.128: W/System.err(489): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
09-27 23:15:37.128: W/System.err(489): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
09-27 23:15:37.138: W/System.err(489): at android.os.Handler.dispatchMessage(Handler.java:99)
09-27 23:15:37.138: W/System.err(489): at android.os.Looper.loop(Looper.java:123)
09-27 23:15:37.138: W/System.err(489): at android.app.ActivityThread.main(ActivityThread.java:3683)
09-27 23:15:37.138: W/System.err(489): at java.lang.reflect.Method.invokeNative(Native Method)
09-27 23:15:37.138: W/System.err(489): at java.lang.reflect.Method.invoke(Method.java:507)
09-27 23:15:37.138: W/System.err(489): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
09-27 23:15:37.138: W/System.err(489): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
09-27 23:15:37.138: W/System.err(489): at dalvik.system.NativeStart.main(Native Method)
I tried your code this way,
private void jsonTest() {
try {
String jsonString = "{\"success\":1,\"message\":\"Post Available!\",\"posts\":[{\"post_id\":\"1\",\"username\":\"hasni\",\"title\":\"titre\",\"message\":\"this is my message\"},{\"post_id\":\"2\",\"username\":\"user2\",\"title\":\"titre 2\",\"message\":\"this is my message 2\"},{\"post_id\":\"3\",\"username\":\"123\",\"title\":\"12\",\"message\":\"111\"},{\"post_id\":\"4\",\"username\":\"1212\",\"title\":\"1212\",\"message\":\"1212\"},{\"post_id\":\"5\",\"username\":\"1212\",\"title\":\"bonjour\",\"message\":\"voila ce message qui vient d'une session \"},{\"post_id\":\"6\",\"username\":\"121212\",\"title\":\"titre\",\"message\":\"message\"}]}";
Log.i(TAG, "jsonString = " + jsonString);
JSONObject json = new JSONObject(jsonString);
int success = json.getInt("success");
Log.d("ok", "ok");
if (success == 1) {
JSONArray messagesArray = (JSONArray) json
.getJSONArray("posts");
for (int i = 0; i < messagesArray.length(); i++) {
Log.d("iteration", "iteration" + i);
JSONObject messageJson = messagesArray.getJSONObject(i);
Log.d("post_id",
"post_id: " + i + " "
+ messageJson.getString("post_id"));
Log.d("username",
"username: " + i + " "
+ messageJson.getString("username"));
Log.d("title",
"title: " + i + " "
+ messageJson.getString("title"));
Log.d("message",
"message: " + i + " "
+ messageJson.getString("message"));
}
} else {
Log.d("failed", "!!!!!!!!!!!!!!!!!!!!!!!!");
}
} catch (Exception e) {
// TODO: handle exception
e.printStackTrace();
}
}
And worked properly, may be something wrong with your TAGs that you have defined.