Useful android java snippets

snippet.java

//JSON Load from file to object
    public JSONObject loadJSONFromAsset() {
        String json = null;
        try {
        	//Points towards top level assets folder
            InputStream is = getApplicationContext().getAssets().open("filename.json");
            int size = is.available();
            byte[] buffer = new byte[size];
            is.read(buffer);
            is.close();
            json = new String(buffer, "UTF-8");
        } catch (IOException ex) {
            ex.printStackTrace();
            return null;
        }
        return JSONObject object = new JSONObject(json);
    }


//Download JSON from API
    private void downloadData() {
        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    String dataString = "";
                    URL url = new URL("DATAURL");
                    HttpURLConnection conn = (HttpURLConnection) url.openConnection();

                    int responseCode = conn.getResponseCode();
                    System.out.println("Code: " + responseCode);

                    if (responseCode == HttpURLConnection.HTTP_OK) {

                        BufferedInputStream is = new BufferedInputStream(
                                conn.getInputStream());
                        BufferedReader br = new BufferedReader(new InputStreamReader(is));

                        String line;

                        while ((line = br.readLine()) != null) {
                            dataString += line;
                        }

                        //... Process data here

                        br.close();
                        is.close();
                        conn.disconnect();
                    } else {
                        throw new IllegalStateException("HTTP response: " + responseCode);
                    }

                } catch (IOException e) {

                    System.out.println("Error Downloading Json");
                    e.printStackTrace();
                }
            }
        });
    }

//Read and write JSON and strings to Shared prefs
//Instantiate prefs
SharedPreferences sharedPref = getApplicationContext().getSharedPreferences("MYPREFS", getApplicationContext().MODE_PRIVATE);

//Get String
String dataString = sharedPref.getString("STRINGNAME", "");
//IFJSON
JSONArray dataArray = new JSONArray();
if (!dataString.isEmpty()) {
    dataArray = new JSONArray(dataString);
}

//Update JSON
JSONObject json = new JSONObject();

json.put("KEY", "ITEMTOSTORE");
dataArray.put(json);

//Write JSON to Prefs
String newDataString = dataArray.toString();
SharedPreferences.Editor editor = sharedPref.edit();
editor.putString("STRINGNAME", newDataString);
editor.apply();