Develop Reference

Android - How to Represent JSON Information from URL through GSON

I have been attempting to retrieve information from an online JSON Source using a URL. I initially got the information parsed to a TextView in Android, however I got ALL Information from the JSON. Below is a screenshot of what I am referring to.
Text View Showing All Data In Json
Essentially, What I want is to just show the Location, so in the above example, Oslo, in Norway in one Textview, then in another show the Current Moon Phase for that location, so - using the above example again, Waxing Crescent.
This is the JSON I am using.
{
"version": 2,
"locations": [{
"id": "187",
"geo": {
"name": "Oslo",
"country": {
"id": "no",
"name": "Norway"
},
"latitude": 59.913,
"longitude": 10.740
},
"astronomy": {
"objects": [{
"name": "moon",
"days": [{
"date": "2018-09-13",
"events": [],
"moonphase": "waxingcrescent"
}]
}]
}
}]
}
To parse the JSON to the Textview showing all the data I used the following.
JSONObject jo = new JSONObject(data);
JSONArray locations = jo.getJSONArray("locations");
for (int i = 0; i < locations.length(); ++i) {
JSONObject loc = locations.getJSONObject(0);
JSONObject geo = loc.getJSONObject("geo");
JSONObject country = geo.getJSONObject("country");
JSONObject astronomy = loc.getJSONObject("astronomy");
JSONObject objects = astronomy.getJSONArray("objects").getJSONObject(0);
JSONObject day = objects.getJSONArray("days").getJSONObject(0);
StringBuilder result = new StringBuilder();
String singleParsed = "Moon: "+ astronomy.getString("moonphase");
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
#RequiresApi(api = Build.VERSION_CODES.CUPCAKE)
#Override
protected void onPostExecute(Void aVoid) {
super.onPostExecute(aVoid);
MainActivity.fetcheddata.setText(this.data);
}
NOTE: A String is created in the For Loop, Called "Single Parsed", This is what I want to put on the screen, however - once I call that variable, nothing shows on the screen. It only shows when using:
MainActivity.fetcheddata.setText(this.data);
But Not with the following, I do actually receive an error saying "Cannot Resolve Symbol, singleParsed as well.
MainActivity.fetcheddata.setText(this.singleParsed);
After some research and previous questions on Stack, I believe GSON is the way to go to do what I wish, however I have no idea where to start, or how to do the task using GSON.
All help is appreciated.

JSON Information from URL through GSON
Simple answer - Look at using Retrofit, and find a tutorial on it, as well as Gson
However
You don't need Gson to fix your problem, and I suggest fixing the problem at hand rather than going down an unnecessary path.
First, singleParsed is a local variable within a loop. Therefore, this.singleParsed doesn't exist. Or if it does, you never set it.
Secondly, let's assume you only have one location, so you don't need a loop. Similar to how you accessed the other JSON arrays, just get the first array item.
Finally, you'll need to understand how AsyncTask works, but my general recommended solution is at How to get the result of OnPostExecute() to main activity because AsyncTask is a separate class?
But, for this purpose, here is a simple example with AsyncTask<String, Void, String>
// protected String doInBackground(String... url) { // I assume you have this ??
// String data = parseJsonFrom(url[0]);
String singleParsed = "(none)";
try {
JSONObject jo = new JSONObject(data);
JSONObject firstLocationAstronomy = jo
.getJSONArray("locations").getJSONObject(0)
.getJSONObject("astronomy");
JSONObject firstDay = firstLocationAstronomy
.getJSONArray("objects").getJSONObject(0)
.getJSONArray("days").getJSONObject(0);
singleParsed = firstDay.getString("moonphase");
} catch (Exception e) { // TODO: catch a JSONParseException
}
return singleParsed; // This is returned to onPostExecute, don't store a variable elsewhere
}
Then in the MainActivity, wherever you make this task, and set the text
new MoonPhaseTask() {
#Override
protected void onPostExecute(String moonPhase) {
MainActivity.this.textView.setText("Phase: " + moonPhase);
}
}.execute("some url");
What I want is to just show the Location, so in the above example, Oslo, in Norway in one Textview, then in another show the Current Moon Phase for that location
You can change the AsyncTask to return you the entire JSONObject to the onPostExecute, and parse the JSON there if you really wanted. Just the networking pieces need to be off the UI thread... parsing is not computationally expensive.

How to make fast my android app while using json feeds from server

i have generated an app over e-commerce site (magento 2) while i am trying to startup my app it processing very slowly because of many products in my server is there any possible way to speed up my usage of Async task while using JSON feeds.. Please let me for any possible ways
My one of the AsyncTask coding:
private class GetProduct extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
// Showing progress dialog
dialog_pro = new ProgressDialog(Healthy_Cat.this);
dialog_pro.setMessage("Please wait...");
dialog_pro.setCancelable(false);
dialog_pro.show();
}
#Override
protected Void doInBackground(Void... arg0) {
HttpHandler sh = new HttpHandler();
String jsonStr = sh.makeServiceCall(url);
if (jsonStr != null) {
try {
JSONArray items = new JSONArray(jsonStr);
for (int i = 0; i < items.length(); i++) {
JSONObject c = items.getJSONObject(i);
pro_name = c.getString("name");
String price = c.getString("price");
JSONArray array = c.getJSONArray("custom_attributes");
for (int k = 0; k < array.length(); k++) {
JSONObject jb = array.getJSONObject(k);
String attr = jb.getString("attribute_code");
if (attr.equalsIgnoreCase("special_price")) {
splprice = jb.getString("value");
}
}
String sku = c.getString("sku");
JSONArray media = c.getJSONArray("media_gallery_entries");
for(int k = 0; k < media.length(); k++) {
JSONObject jb = media.getJSONObject(k);
String imageURL = BaseURL_Helper.MediaBase +jb.getString("file");
media_image = imageURL;
// tmp hash map for single contact
Beanclass dataSet = new Beanclass();
dataSet.setTitle(pro_name);
dataSet.setImage(imageURL);
dataSet.setPrice(price);
dataSet.setSPLPrice(splprice);
dataSet.setSku(sku);
list.add(dataSet);
BeanclassList data = new BeanclassList();
data.setTitle(pro_name);
data.setImage(imageURL);
data.setSku(sku);
data.setSPLPrice(splprice);
data.setPrice(price);
listbean.add(data);
}
}
}catch (final JSONException e) {
runOnUiThread(new Runnable() {
#Override
public void run() {
no_list.setVisibility(View.VISIBLE);
}
});
}
} else {
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"May be Network error!!",
Toast.LENGTH_LONG)
.show();
}
});
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
// Dismiss the progress dialog
/**
* Updating parsed JSON data into ListView
* */
if (dialog_pro.isShowing())
dialog_pro.dismiss();
mAdapter = new GridviewAdapter(Healthy_Cat.this,list);
gridlist.setAdapter(mAdapter);
Listadapter = new ListviewAdapter(Healthy_Cat.this,listbean);
listview_pro.setAdapter(Listadapter);
}
}
Thank u in advance..

There are few things you need to update in your code
API Calling lib: I'm using Retrofit for api calling very fast & simple to use. Support Header & Response caching too.
JSON Parsing: You are parsing JSON manually which is a time-consuming process. I'm using Google's JSON parsing Lib Gson. really very fast.
Pagination: If you having lots of data on the server then try to fetch data in small no of pieces. For example in case of "Item Listing API" try to fetch data from the server for 10-15 item at a time rather all the item at a once.

Asyntask performance speed is too low compare to Retrofit.
So For e-commerce app, You must use Retrofit.

There are a few things you can do. For starters, you don't have to parse the whole json, before updating view.
But really you yourself state the issue, which is you have too much data. This is not only a programming issue, it is also a user experience issue, too much data is confusing, especially on a mobile device.
What I suggest is breaking down your data into categories or the like. When app starts, download just a list of categories to display. Upon user choosing a category, then you download the data for that category.
When you download data, do it in chunks, so that you can start displaying right away.
There are many similar ideas that you can implement, for a better user experience.

Android Volley request weird "1 second" delay between multiple fast clicks

Sorry for my bad english, but i have problem and can't figure it out..
I have custom listview in my fragment for getting products from JSON array. And I have 3 ImageButtons in every listview row;
Plus Button(+), Minus Button(-) and Remove Button(X)..
So when i click each button, its calling JSON request for update product's piece number, getting new datas from response and repopulate array list.
Everything ok but, when I click that buttons faster, it seems there is 1 sec delay between multiple requests even first volley request has already done before.
Here is my JSON method in TableAdapter.java
public void JSON(final int position, final int process) {
if (inProgress==false) {
dialog = new ProgressDialog(myContext);
dialog.setMessage("Updating.....");
dialog.show();
inProgress = true;
System.out.println("**** Now request is beginning............");
final int rowID = tableModelList.get(position).getID();
final int treeID = tableModelList.get(position).getAna_dal();
final float price = tableModelList.get(position).getBFiyat();
final int quantity = tableModelList.get(position).getAdet();
final int print = tableModelList.get(position).getYazdimi();
final String insertUrl = "http://"+getServer+"/t6mobilservice/order-piece.php";
Map<String, String> parameters = new HashMap<>();
parameters.put("tableID", "" + getTableId);
parameters.put("rowID", "" + rowID);
parameters.put("treeID", ""+treeID);
parameters.put("process",""+process);
parameters.put("quantity",""+quantity);
parameters.put("price",""+price);
parameters.put("print",""+print);
CustomRequest jsObjRequest = new CustomRequest(Request.Method.POST, insertUrl, parameters, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONArray getOrders = response.getJSONArray("order");
Gson gson = new Gson();
tableModelList.clear();
for (int i = 0; i < getOrders.length(); i++) {
JSONObject order = getOrders.getJSONObject(i);
TableModel tableModel = gson.fromJson(order.toString(), TableModel.class);
tableModelList.add(tableModel);
}
mAdapter.notifyDataSetChanged();
System.out.println("**** onResponse: Request is done............");
System.out.println("**** JSON: "+response.toString());
dialog.cancel();
inProgress = false;
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError response) {
Log.d("Response: ", response.toString());
inProgress = false;
}
});
requestQueue.add(jsObjRequest);
}
}
Dialog is showing when request beginning and canceling when request is done. But as I said, when I click faster, there is a delay between multiple requests even first request has already done. I'm saying 1 sec, because 2nd request is beginning after 1 sec exactly, no matter how I clicking fast. I can't figure it out..
I tested fast clicks to showing toasts with random numbers and it's working fine. But when I testing with JSON method, there is a weird delay.
I have SwipeRefreshLayout and ScrollView in my fragment.
I'm using Volley with singleton.
EDIT 1. : Here's a video link to showing what my problem is..
EDIT 2. : Here's a LogCat output video for every click
Every fast click has returning success json output, but nothing change instantly..
Thanks for your help.

setting the adapter in my listview with the loading indication

Below is my code and I get the data from the webservice(remote server) in the doinbackground(). I want to set the data on the UI. Everything works fine. But as I have huge amount of data to be retrieved from the server, the progress bar is showing for a long time. So, I decided to use something like CW endlesss adapter or according to this. It's been giving me grief for few days by now.
1) CW endless adapter: I face a lot of problems in including it as a library project and when I try to run demos, it always shows me ! symbol in red color. When I click on run, it says your project has errors, but there is not even a single clue where does that error occur. Even I am unable to understand the things that have to be done too as those are somewhat difficult for me as a beginner. So, I decided to follow as per the other.
2) In this, I am unable to get on how to use this in my scenario as I am getting the data as a whole after completion of the doInBackground().
Can someone help me on this with relevant code snippets? I would be very thankful for your help.
I am calling this asynctask in onCreate() method.
class LoadAllData extends AsyncTask<String, String, String> {
/**
* Before starting background thread Show Progress Dialog
* */
#Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(GetData.this);
pDialog.setMessage("Loading Data. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(false);
pDialog.show();
}
/**
* getting All Data from url
* */
protected String doInBackground(String... args) {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("datatobefetched", datadetails));
// getting JSON string from URL
JSONObject json = jParser.makeHttpRequest(url_all_ads, "POST", params);
Log.d("All Products: ", json.toString());
try {
// Checking for SUCCESS TAG
int check = json.getInt(CHECK);
if (Check == 1) {
// Data found
// Getting Array of Data
dataJsonArray = json.getJSONArray("totaldata");
// looping through All data
for (int i = 0; i < dataJsonArray.length(); i++) {
JSONObject jobj = dataJsonArray.getJSONObject(i);
// Storing each json item in variable
String id = jobj.getString("rowid");
String product = jobj.getString("data1");
String review = c.getString("data2");
String imagepath = c.getString("image_url");
// creating new HashMap
HashMap<String, String> map = new HashMap<String, String>();
// adding each child node to HashMap key => value
map.put("id", id);
map.put("product", product);
map.put("review", review);
map.put("imageurl", imagepath);
// adding map to ArrayList
productsList.add(map); // ProductList is arrayList.
}
}
else {
// no data found
}
}
catch (JSONException e) {
e.printStackTrace();
}
return null;
}
/**
* After completing background task Dismissing the progress dialog
* **/
protected void onPostExecute(String file_url) {
// dismiss the dialog after getting all products
pDialog.dismiss();
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
// Updating parsed JSON data into ListView
// Getting adapter by passing xml data ArrayList
ListView list = (ListView)findViewById(R.id.list);
adapter = new CustomListAdapter(GetAllAds.this, productsList, passedcategory);
list.setAdapter(adapter);
}
});
}
}

with the code you posted there doesn't seem to have anything that would be taking an awful a lot of time.
I don't believe making an endless list (either using the endless adapter or manually) is the case for you because apparently the web-server you're communicating with does not have the options for page (e.g. when on the URL you specific items per page and page number like this: ?per_page=20&page_no=1) and those type of list only makes sense for such.
Just as a simple test, put those lines before after your code:
long now = System.currentTimeMillis();
JSONObject json = jParser.makeHttpRequest(url_all_ads, "POST", params);
Log.d("Test", "Elapsed time is: " + Long.toString(System.currentTimeMillis() - now));
then you can check on your LogCat how long did it took to make the http request.
edit:
suggested alternative to HashMap<> as I don't believe they are very efficient ways of storing data.
public class MyData(){
JSONObject data;
public MyData(JSONObject data){ this.data=data; }
public String getId(){ return data.getString("rowid"); }
// repeat for the other info you need, also override the toString to return the data.toString();
}
that way all the JSON parsing will be done at a later point in time and in small batches and your for loop would be as simple as:
for (int i = 0; i < dataJsonArray.length(); i++) {
productList.add(new MyData(dataJsonArray.getJSONObject(i));
}

Read random status from a page using facebook api

I am creating an android app for my facebook page. The app is supposed to display random statuses(not just the recent ones) from the facebook page. Is there anyway I could do this?

I haven't done anything of that kind ever, but I think you can gran some logic from this and get it to work.
Step 1:
Make a call to the Facebook API, get all Status Updates and in a for loop, add them to an ArrayList<String>. For example, Facebook returns its data in JSON format. I am assuming, you already know how to fetch data. You need to parse the "message" tag from the JSON data returned by your Facebook API call.
For example:
ArrayList<String> arrStatusMessage;
for (int i = 0; i < JAFeeds.length(); i++) {
JSONObject JOFeeds = JAFeeds.getJSONObject(i);
if (JOFeeds.has("message")) {
String strStatusMessage = JOFeeds.getString("message");
arrStatusMessage.add(strStatusMessage );
}
}
Step 2:
Once you have your entire set of Facebook Status Messages, you will now need to use a java.util.Random instance.
For example: (Please note: I have not tested this code and it might result in errors. You may have to play around with it a bit to get it to work. :-( )
private static final Random randomGenerator = new Random();
int intRandom = randomGenerator.nextInt(arrStatusMessage.size());
String strRandomStatus = arrStatusMessage.get(intRandom);
Step 3:
Use the strRandomStatus to set it on a TextView.
For example:
TextView txtRanStatus = (TextView) findViewById(R.id.txtRanStatus);
txtRanStatus.setText(strRandomStatus);
You haven't posted any code, so it is difficult to provide something that fits in your scheme of things. But I think this should get you started. You will, possibly, need to adapt a few things and fit them in your own code.
Hope this helps.
EDIT: As per a comment by th OP, adding some bits of code to fetch Facebook Status Messages:
in your onCreate() method:
Start a new AsyncTask:
new getFacebookFeeds().execute();
I use this method in my app to make the Facebook Call to get all feeds from the Graph API.
private class getFacebookFeeds extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
String URL = "https://graph.facebook.com/me/home&access_token=ACCESS_TOKEN?limit=10";
try {
HttpClient hc = new DefaultHttpClient();
HttpGet get = new HttpGet(URL);
HttpResponse rp = hc.execute(get);
if (rp.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
String result = EntityUtils.toString(rp.getEntity());
// GET THE INTIAL RESULTS JSON ROOT
JSONObject JORoot = new JSONObject(result);
// GET THE "DATA" TAG FOR FEEDS ROOT
JSONArray JAFeeds = JORoot.getJSONArray("data");
for (int i = 0; i < JAFeeds.length(); i++) {
JSONObject JOFeeds = JAFeeds.getJSONObject(i);
if (JOFeeds.has("message")) {
String strStatusMessage = JOFeeds.getString("message");
arrStatusMessage.add(strStatusMessage );
}
}
}
} catch (Exception e) {
// TODO: handle exception
}
}
}
You can do the remaining code, where you select a random Status Update, in the onPostExecute() of the AsyncTask shown above:
#Override
protected void onPostExecute(Void result) {
int intRandom = randomGenerator.nextInt(arrStatusMessage.size());
String strRandomStatus = arrStatusMessage.get(intRandom);
txtRanStatus.setText(strRandomStatus);
}
Declare the TextView as a Global Variable and cast it on your onCreate() before calling the AsyncTask. I think this should work just fine. Let me know how it goes. :-)