Android Firebase - cannot get the correct JSON from a Firebase snapshot

Question

My Android application connects to Firebase and pulls out “Alert Objects” that are sent to my server.

When I export data from Firebase, I get a beautifully formed JSON representation of the data.

Problem: When I pull data to my Android device using DataSnapshot, the data has "=" (equal to signs) instead of ":" (semicolon). There are also no quotes.

When I try to do something like JSONObject alert = new JSONObject(data.getValue().toString()); I get errors for obvious reasons. I say, obviously, because if you look at what my code prints to the console, you can see that it is no longer in the actual JSON format.

A friend mentioned that I needed to do something with the encoding, but we did not have time to discuss this.

How can I iterate over these (curious) Alert objects that I created and turn them into JSON objects in my Java so that I can access their properties like alert.date and alert.message .

I thought the screenshots would help you understand what I am doing. Firebase is not protected at all, so you can freely look at it. It will not be very much, and when I go to production, I will transfer it anyway.

I'm sure this is a very simple question to answer, I'm just not too good at JSON and coding in general.

Thanks!

Answer 1

You cannot access JSON natively in Java.

But the Firebase DataSnapshot class provides everything you need.

If you have a DataSnapshot data on fbAlerts in the screenshot, you can print the date + message and recipients for each:

 for (DataSnapshot alert: alerts.getChildren()) { System.out.println(alert.child("date").getValue(); System.out.println(alert.child("message").getValue(); for (DataSnapshot recipient: alert.child("recipients").getChildren()) { System.out.println(recipient.child("name").getValue(); } } 

Alternatively, you can create a Java class that represents a warning. See the Firebase Android Reading Guide . Examples.

Answer 2

you can use gson library

  public void onChildAdded(DataSnapshot dataSnapshot, String s) { /*JSONObject jsonObject = null; try { jsonObject=new JSONObject(); } catch (JSONException e) { e.printStackTrace(); }*/ Gson gson = new Gson(); String s1 = gson.toJson(dataSnapshot.getValue()); JSONArray object = null; try { object = new JSONArray(s1); } catch (JSONException e) { e.printStackTrace(); } JSONArray jsonArray = object; Log.e("string", s1); } 

Answer 3

Use this method to convert jsonObject form to dataSnapshot

 Map<String, String> value = (Map<String, String>) dataSnapshot.getValue(); Log.i("dataSnapshot", "dataSnapshot" + new JSONObject(value)); 

Answer 4

From the above code, you will see that you have a JSONArray, not a JSONObject.

In this case, you need to do something like the following:

 // Find the right array object JSONArray jsonArray = response.getJSONArray("fbAlerts"); // Loop through the array for (int i=0; i< jsonArray.length(); i++) { JSONObject myObj = jsonArray.getJSONObject(i); strMsg = myObj.getString("message"); } 

In the example, when you repeat groups, this apparently points to an array and therefore needs an iterator to access the contents of the object.