Can ajax call be done in Android? - android

I'm developing an application in which I've got search option. In that search box, if I type 'a' I want all names of all my friends starting with a, which I'll get from web server. But for that I've to make request simultaneously with typing each letter. But when I googled, I got mixed reactions. Some people said Ajax call is not possible in Android. Basically Android is based on java. Then why is not possible to perform AJAX calls. Could anyone guide me to a good link related to AJAX call in Android if it is possible ?

You can use droidQuery, which is The Android port of jQuery, and includes most of the features and syntax of jQuery, including Ajax. For example:
$.ajax(new AjaxOptions().url("http://www.example.com").type("GET").dataType("json").success(new Function() {
#Override
public void invoke($ d, Object... args) {
JSONObject json = (JSONObject) args[0];
//TODO handle json. If expecting a JSONArray, just cast args[0] to JSONArray.
}
}).error(new Function() {
#Override
public void invoke($ d, Object... args) {
AjaxError error = (AjaxError) args[0];
Toast.makeText(MyActivity.this, "Error (" + error.status + "): " + error.reason, Toast.LENGTH_LONG).show();
}
}));

Yes it is possible, but with a few conditions and restrictions.
Check out these resources for more info:
Can you use AJAX calls with Android?
Android: Implication of using AsyncTask to make repeated Ajax Calls
https://developer.android.com/guide/topics/search/search-dialog.html
http://www.grokkingandroid.com/android-tutorial-adding-search-to-your-apps/

Closest I know is using an AutoCompleteTextView. You will need to make a custom adapter for it that makes calls to the web server whenever a user types anything and returns filter results based on that.
Here's an example.

Fetch names from the server on loading the screen, using asynctask.
Then you can make use of AutoCompleteTextView or MultiAutoCompleteTextView to achieve your need.
You specify already fetched names in the adapter. See more on AutoCompleteTextView
and MultiAutoCompleteTextView

Related

Is ther any way to load text after building game for android in unity

I had created a small android game that had some character names and some values, I want to control the names and value so that I change value whenever I need. I searched online but I didn't find any quick solution for that. Is there any way to control the values online through some web service so that I can change value online and it will create changes in my game?
You'd need a server to store your data, even GitHub would do and it has free plan.
Then your code needs to be designed so it takes those.
Here could be a short example. This is what you have on github:
{
"characterName" : "Buldor",
"strength" : 10
}
You'd need a C# version of that:
[Serializable]
public class Response
{
public string characterName = null;
public int strength = 0;
}
Then you'd need a loading screen on your game where you fetch the info from the server and assign them. It means your game is no longer valid offline (or you'd used previous loaded or default values).
void Start()
{
StartCoroutine(GetText());
}
IEnumerator GetText()
{
using (UnityWebRequest www = UnityWebRequest.Get("github_url"))
{
yield return www.Send();
if (www.isNetworkError || www.isHttpError)
{
Debug.Log(www.error);
}
else
{
// Show results as text
Debug.Log(www.downloadHandler.text);
Response res = JsonUtility.FromJson<Response>(www.downloadHandler.text);
PlayerPrefs.SetString("characterName", res.characterName);
PlayerPrefs.SetInt("strength", res.strength);
}
}
}
}
And finally, you have the character class:
public class Character : MonoBehaviour
{
void Start(){
string characterName= PlayerPrefs.GetString("characterName", "OldName");
int strength = PlayerPrefs.GetInt("strength", 0);
}
}
So to sum it up, first create a json to store on a server, get the url of the location.
Then download the file, it can be json, xml, txt or anything, but make sure you know how to parse it and json already have it all so more simple.
Then parse the file and store the values, either in PlayerPrefs like I did or directly into the player.
Then extend the json file to store more info.
Yes this is possible! You can use the database like Mongo, Redis or MySQL, it depends on your value! And work with the POST or GET HTTP request to get the value! And for the back-end, you can use Golang, PHP, or anything you can! If you have a game with many users my offer is Golang!
And you can use these link to work with and POST Get in unity:
https://docs.unity3d.com/ScriptReference/Networking.UnityWebRequest.Get.html
https://docs.unity3d.com/ScriptReference/Networking.UnityWebRequest.Post.html
Good luck! If you have a question about Golang or PHP code you can ask me! :))

Recommended way / order to read data from a webservice, parse that data and insert it in a SQLite db

I'm one to start mentioning that I'm totally new to Android, I've just finished reading a quick, introductory book and now I have to implement my very first app.
This app is going to be use to take orders. Among all the data I'm going to store in a local db, two tables are the most important: Customers and Articles, being the latter the largest of all the tables (aprox 20000 records)
One of the main process in my app, fetches all the data that my app need to work off-line when the user press a button that starts the daily operations on the device.
Well, the process consists of the following steps :
a. Read a restful service to retrieve the Customers Data
b. Parse the response to Json Objects
c. Insert those customers to the Customers Table
d. Read a restful service to retrieve the Articles Data
e. Parse the response to Json Objects
f. Insert those articles to the Articles Table
This is what I've planned to do:
Write a helper class that handles all the HTTP GET requests. Then call this class whenever I need to download all the Customers and Articles data
Since all this process might take a lot of time, I need to do it the background. So based on some suggestions I'm going to put all this code inside a Bound Service.
While all this long processing is taking place in the background I'll have to show some sort of indicator (a ProgressDialog) This is the reason I opted for using a Bound Service
Though I think I've got the general idea of how to do most of these thing separately, I think that putting the all together is quite a different story.
So these are the questions I've got now that I have to put the puzzle together:
Do you think the order in which I'm executing all the 6 steps of the process described is correct / efficient? If you had to make some changes, what would you change?
If the activity that started the service is explicitly cancelled or is hidden by another activity, the service has to have a way to let the user know that the process has finished. How could I implement that?
Is it possible/ recommended to write to the SQLite DB within the service? Is it the same as when I do so within an activity?
In J2ME I've done something similar, and when I put something like the 6 steps I mentioned above all of them are executed sequentially, that is , one after the other. Is it the same in Android?
I hope I'm not asking too many questions. I just put them together because they are all related.
Basically in this question I'm not asking for working code ( though it'd be OK if you could provide some sample code) What I'm really after is some suggestions, some guidance. Something like "Hey, I think this might help you with point number 3" or "You might find this article useful", "I think you'd better off using this instead of that". That kind of thing.
I decided to come to you because you're the experts and I really need someone to put me in the right direction.
Thank you very much.
P.S. Please do not close this question, if your think I need to change something just let me know and I'll do it.
I decided to come to you because you're the experts
first i am not expert and also i am not knowledgeable you can find more expert people than me but this is my opinion hope to give you some help.
first of all forget to use AsyncTask to download because it must be used for short background jobs not like yours i think the amount of file you want to download is pretty large.(i think so)
check downloadmanager of google to see how it works it may help you.
http://developer.android.com/reference/android/app/DownloadManager.html
http://blog.vogella.com/2011/06/14/android-downloadmanager-example/
if you want to use service use unbound service because you do not want the service to be destroyed by android or user when the user close the apps do you? i think you want to get your data any way.
in order to be efficient i recommend these steps:
a. Read a restful service to retrieve the Customers Data
b. when you get Customer data do :
create another service or thread to Read a restful service to retrieve the Articles Data
Parse the response to Json Objects on your old service or thread
now you have 2 services or threads that run concurrently so follow the steps that obvious insert parse and so, on each service or thread.
why do not i combine a and d? because i think user do not like to wait much time behind download progress bar.
in order to insert your data to database use transaction and i recommend you use:
http://greendao-orm.com/
it is more efficient ORM than others for database and you get free from db implementation.
If the activity that started the service is explicitly cancelled or is hidden by another activity, the service has to have a way to let the user know that the process has finished. How could I implement that?
use notification:
http://developer.android.com/training/notify-user/build-notification.html
http://www.tutorialspoint.com/android/android_notifications.htm
http://www.vogella.com/tutorials/AndroidNotifications/article.html
While all this long processing is taking place in the background I'll have to show some sort of indicator (a ProgressDialog) This is the reason I opted for using a Bound Service`
how can I update the UI from an Unbound Service?`
Use a LocalBroadCastManager, or in general BroadCastReciever
Android update activity UI from service
In J2ME I've done something similar, and when I put something like the 6 steps I mentioned above all of them are executed sequentially, that is , one after the other. Is it the same in Android?
this is depends on your steps, if you follow my idea you run concurrently and if you run your idea you will run sequentially.
Good Luck.
I did something like yours.
In first step I get data from webservice in HTTP GET of POST method using AsyncTask like this:
public class GetService extends AsyncTask<String, String, String> {
private String mRestUrl;
private ServiceCallback mCallback;
private final HttpClient Client = new DefaultHttpClient();
private String Content;
private String url;
private String Error;
private ProgressDialog barProgressDialog;
private ProgressDialog Dialog;
public GetService(String restUrl, ServiceCallback callback) {
this.mRestUrl = restUrl;
this.mCallback = callback;
this.url = restUrl;
Dialog = new ProgressDialog(AppContext.CurrentContext);
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... urls) {
Content = null;
BufferedReader reader = null;
try {
StringBuilder builder = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpGet get = new HttpGet(this.url);
HttpResponse response = client.execute(get);
int status = response.getStatusLine().getStatusCode();
if (status == 200) // sucess
{
HttpEntity e = response.getEntity();
// String data = EntityUtils.toString(e);
InputStream content = e.getContent();
reader = new BufferedReader(new InputStreamReader(content));
String line;
while ((line = reader.readLine()) != null) {
builder.append(line);
}
Content = builder.toString();
} else if (status == 401) {
return "-Auth Failed Error Code 400";
} else {
return "-Error Code: " + status;
}
} catch (Exception ex) {
Error = ex.getMessage();
} finally {
Dialog.dismiss();
try {
reader.close();
}
catch (Exception ex) {
ex.printStackTrace();
}
}
return Content;
}
#Override
protected void onPostExecute(String result) {
try {
GetService.this.get(20000, TimeUnit.MILLISECONDS);
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (TimeoutException e) {
e.printStackTrace();
}
mCallback.onTaskComplete(result);
super.onPostExecute(result);
}
}
and my callback class is:
public abstract class ServiceCallback{
public abstract void onTaskComplete(String result);
}
I call AsyncTask in my code everywhere I want to get data from webservice:
new GetService(url, new ServiceCallback() {
public void onTaskComplete(String response) {
// Parse Response of WebService
}
}).execute();
In second step I Parse response of WebService in onTaskComplete method using json helper Libraries like Gson or Jackson. for example in jackson:
List<YourClass> data = new ObjectMapper()
.readValue(
response,
new TypeReference<List<YourClass>>() {
});
At the end I store Data in Database. for connecting to DB I Prefer to use GreenDao as my ORM. In this way storin data in DB can be done in one line code like this:
//after converting json to object
YourORMDaoClass.insertOrReplaceInTx(data);
To Use GreenDao ORM this link is very helpful;
Do you think the order in which I'm executing all the 6 steps of the
process described is correct / efficient? If you had to make some
changes, what would you change?
It depends. If this data is related and cannot exists without each other then you should change the order like this:
a. Read a restful service to retrieve the Customers Data
b. Parse the response to Json Objects
d. Read a restful service to retrieve the Articles Data
e. Parse the response to Json Objects
c. Insert those customers to the Customers Table
f. Insert those articles to the Articles Table
Steps c and f should be combined in transaction.
Otherwise, the order does not matter. If data is not related then separating these processes and running them in sequence might be a good idea.
If the activity that started the service is explicitly cancelled or is
hidden by another activity, the service has to have a way to let the
user know that the process has finished. How could I implement that?
I suggest to start with implementation of the IntentService class. It handles for you background thread and works like a queue of events where single Intent delivers a data to process.
Actually you could implement one of the patterns presented by Google on one of their IO conferences. I have implemented an option A shown on the video. It works for me really well. The trick is that using ContentProvider from the background automatically updates UI which listen for changes thanks to CursorAdapter.
To update UI progress you can use LocalBroadcastManager or event bus libraries e.g. Otto.
You can also extend your tables and store status and progress, updating tables would automatically update UI as well, just keep in mind that these updates should be rare e.g. control in the service background how often table progress is updated calculating the progress first and checking with service local variable if it's changed.
In case your app is in the background, post status notification. User should be able to navigate back to your app clicking on the notification.
Is it possible/ recommended to write to the SQLite DB within the
service? Is it the same as when I do so within an activity?
You can do it within the Service. Actually, if you follow the pattern I have mentioned above, you would do it in the Processor tier on the background service thread.
In J2ME I've done something similar, and when I put something like the
6 steps I mentioned above all of them are executed sequentially, that
is , one after the other. Is it the same in Android?
It's completely up to you how communication with the server will work. If you decide to use IntentService class then it will work in a sequence which is not a bad idea on Android. On the other hand you may extend Service class directly and implement own thread executor with a thread pool. You can also have dedicated IntentService classes for unrelated operations.
I also recommend to read lessons:
Transferring Data Without Draining the Battery
Transferring Data Using Sync Adapters
If you don't want to play directly with HTTP connection implementation then consider using Retrofit or Volley
If you just need JSON parsers then these 2 are the best:
GSON
Jackson

Android and Azure Mobile Services: Using invokeAPI to return recordset

I am trying something very simple. I have a custom API called "missingvehiclesfrominventoryjob" and it simply returns a record set from an standard SQL Query.
I can do this in my WinForms and Windows Phone app easily but I cannot figure out how to do this on the Android App.
Here is my code: (which DOES NOT COMPILE in Android Studio):
msClient.invokeApi("missingvehiclesfrominventoryjob", kd, new
ApiOperationCallback<List<InventoryProspects>>(){
#Override
public void onCompleted(List<InventoryProspects> missingVehicles, Exception e,
ServiceFilterResponse serviceFilterResponse){
for (InventoryProspects item : missingVehicles){
mAdapter.add(item);
}
}
});
The problem is the List in the parameters of the Callback. I am not sure how to indicate that the invoiceAPI call will return multiple rows from the database and I cannot find anywhere in the docs to explain how. Nor can I find an example ANYWHERE on the internet.
I am sure I am not the only on trying to do this.
Thanks in advance
Chuck Giddens
What i did to overcome this problem, is to call a different overload of invokeApi that returns a JsonElement, and then deserialise it into my objects like so:
mClient.invokeApi("MyCustomApi",null, "GET", null, new ApiJsonOperationCallback() {
#Override
public void onCompleted(JsonElement jsonElement, Exception e, ServiceFilterResponse serviceFilterResponse) {
GsonBuilder gsonb = new GsonBuilder();
Gson gson = gsonb.create();
JsonArray array = jsonElement.getAsJsonArray();
List<MyObject> myObjects = new ArrayList<MyObject>()>
for(int i = 0; i < array.size(); i++)
{
myObjects.add(gson.fromJson(array.get(i).getAsJsonObject().toString(), MyObject.class));
}
}
});
I haven't had a chance to test it yet (will try when I have time and edit answer as needed) but my thinking is that the Android SDK won't allow you to do what you're trying to do. The invokeApi methods expect a strongly typed class to be set as the response type (or you can use the raw JSON methods). In this case, you're trying to say you want a list of items back, but I don't think that will work. I think you'll instead need to create a new class (i.e. missingvehiclesfrominventoryjobResponse) which contains a property that is of type List< InventoryProspects>. Note that you'll need to change your method call to actually match one of the available options for invokeApi which I don't believe it's doing right now. You can read more about the different formats of the method here: http://blogs.msdn.com/b/carlosfigueira/archive/2013/06/19/custom-api-in-azure-mobile-services-client-sdks.aspx
Alternatively, you can use the table methods against a table endpoint where the read expects a collection of results back.
Have you tried to remote debug your API call from the app.[http://blogs.msdn.com/b/azuremobile/archive/2014/03/14/debugging-net-backend-in-visual-studio.aspx]. Your app will timed out in doing that but you can see line by line execution of your controller action if it returns the correct result set. If there is no problem with it then the problem should be in parsing result set.
What is the exception you are getting in callback? And have you tried using other method parameters such as passing with different HTTP methods? Use this as a reference as well. http://azure.microsoft.com/en-us/documentation/articles/mobile-services-android-get-started/
Please paste your exception or either controller action, and the object structure of the data transfer object of the result set.

improving speed performance on a data call

I am making an API call to a web service from the android application the problem is that it returns around 22000 records, I am loading this into an array after i convert each record into an object then assign that Array to a ListView. What is the fastest/best way to fetch this data from the web service? (buffer) ? and what are the best practices for this type of issues.
I would recommend using a library to handle your data call...
Please try using Android Query; specifically, see the section entitled Asynchronous Network.
This AQuery library (AndroidQuery) is lightweight, and requires only 1 jar SMALL jar file. It can be used with Maven or Gradle Android projects as well. It allows you to EASILY fetch XML or JSON data from a remote server in either asynchronous or synchronous fashion. I have used it many times with a JSON back-end, and it is a real timesaver.
This library also allows you to specify a ProgressBar that will automatically appear and disappear during the network download process.
Here is an example of an HTTP call to a JSON back-end, asynchronously:
public void asyncJson(){
//perform a Google search in just a few lines of code
String url = "http://www.google.com/uds/GnewsSearch?q=Obama&v=1.0";
aq.ajax(url, JSONObject.class, this, "jsonCallback");
}
public void jsonCallback(String url, JSONObject json, AjaxStatus status) {
if(json != null) {
//successful ajax call
} else {
//ajax error
}
}
AQuery can also simplify other aspects of Android programming (such as eliminating the findViewById() calls for many scenarios).

Android App and REST API

I searched for good REST / HTTP Clients for Android-Development, but I did not found something that meets my needs.
Now I have a question. Is there a good way to reuse HTTP client-objects in an android project?
It would be good if there is a central place (maybe static class?) to access an httpclient to do request (async)...
How can I do this in an android project?
Same thing for my credentials. (I use basic auth and do not want to pass the credentials from activity to activity)
I would recommend you RoboSpice:
RoboSpice is a modular android library that makes writing asynchronous
network requests easy.
It does have a cache manager, and works as service, which is, to me, better than common AsyncTasks.
https://github.com/octo-online/robospice
Also, you should not touch the R class, it is automatically built from your ressources.
I suggest checking out
https://github.com/posco2k8/rest_loader_tutorial
I would also suggest a minor improvement change RESTLoader.RESTResponse data so as data be the final data in that case List<String> so as the parsing moved to the acync loader and avoid latency on UI thread. Adding the code pointing out the suggestions for change.
#Override
public void onLoadFinished(Loader<RESTLoader.RESTResponse> loader, RESTLoader.RESTResponse data) {
int code = data.getCode();
String json = data.getData(); // <-- (change) this should be the final data
// Check to see if we got an HTTP 200 code and have some data.
if (code == 200 && !json.equals("")) {
// For really complicated JSON decoding I usually do my heavy lifting
// Gson and proper model classes, but for now let's keep it simple
// and use a utility method that relies on some of the built in
// JSON utilities on Android.
List<String> tweets = getTweetsFromJson(json); // <-- (change) that parse move to loader
// Load our list adapter with our Tweets.
mAdapter.clear();
for (String tweet : tweets) {
mAdapter.add(tweet);
}
}
else {
Toast.makeText(this, "Failed to load Twitter data. Check your internet settings.", Toast.LENGTH_SHORT).show();
}
}
As said RoboSpice is a very good choice. If you want to simply keep your local resource syncronized with remote data you can use RestDroid which is a "resource oriented" library to handle asynchronous REST request.

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