Develop Reference

Why toast does not show in asynctask?

I'm beginner in android and trying to show toast in the async task, for that purpose I wrote this code:
public class GetReading {
public GetReading() {
}
public List<ReadingModel> Get(String TokenKey, Context adapter) throws ExecutionException, InterruptedException {
GetReadingTask params = new GetReadingTask(TokenKey, adapter);
List List_result = (List)(new GetReading.AsyncRead()).execute(new GetReadingTask[]{params}).get();
return List_result;
}
private class AsyncRead extends AsyncTask<GetReadingTask, Void, List<ReadingModel>> {
ir.behineh.wepapiinterface.GETREADINGINTERFACE.ReadingModel.List x;
private AsyncRead() {
}
protected List<ReadingModel> doInBackground(GetReadingTask... getReadingTasks) {
final Context pos = getReadingTasks[0].adapter;
Handler handler = new Handler(pos.getMainLooper());
handler.post(new Runnable() {
public void run() {
Toast.makeText(pos, "Created a server socket", 1).show();
}
});
ir.behineh.wepapiinterface.GETREADINGINTERFACE.GetReading taskService = (ir.behineh.wepapiinterface.GETREADINGINTERFACE.GetReading)ServiceGenerator.createService(ir.behineh.wepapiinterface.GETREADINGINTERFACE.GetReading.class);
Call tasks = taskService.getReadings("application/x-www-form-urlencoded", "application/json", "bearer " + getReadingTasks[0].TokenKey);
try {
this.x = (ir.behineh.wepapiinterface.GETREADINGINTERFACE.ReadingModel.List)tasks.execute().body();
} catch (IOException var7) {
var7.printStackTrace();
}
return this.x;
}
}
}
and when i try to call that async task with this code:
GetReading reading=new GetReading();
List<ReadingModel> result= reading.Get("VQ",LineActivity.this);
after finishing doinbackground get the toast, but i want to show toast first to user, what happen? how can i solve that problem? thanks all.

Toasts as well as anything that has to do with the UI cannot be fired from any thread that runs in the background.
Move your code for displaying the toast to either onProgressUpdate or on onPostExecute.

All your troubles arise because you use the .get() in
execute(new GetReadingTask[]{params}).get();
Never use .get() as it kills the asynchonity of your task.
Instead: do the things you want to do with the result in onPostExecute().

How can use update UI Thread

I have same stock item , I want to send local database to ApiService, But when I send also I want to update ProgressBar message. I tried the code below but it just shows when all proccessing is finishing.
ProgressDialog progress= new ProgressDialog(this);
progress.setTitle(getResources().getString(R.string.progress_exporting));
progress.setMessage("0/0");
when click button I call below method
public void Export() {
runOnUiThread(new Runnable() {
#Override
public void run() {
findViewById(R.id.btnExportOnlineWithStocktaking).setEnabled(false);
progress.show();
}
});
UpdateUI(send, total);
try {
switch (_stocktakingType) {
case Division: {
switch (_onlineExportType) {
case Item: {
isExport = ExportDivisionStocktakingItems(stocktakingId);
}
break;
}
} catch (Exception ex) {
}
}
// ExportDivisionStocktaking method
public boolean ExportCustomStocktakingItems(int stocktakingId) {
result = Boolean.parseBoolean(SendCustomStocktakingItems(stocktakingId,countResults).responseString);
}
My call back method
public ResponseModel SendCustomStocktakingItems(int selectedDivision, List<ExtensionServiceStocktakingItem> countResults) throws ExecutionException, InterruptedException {
return new SendCustomStocktakingItemsService(flag -> true).execute(String.valueOf(selectedDivision), countResults.toString()).get();
}
//AsyncTask method
public class SendDivisionStocktakingItemsService extends AsyncTask<String, Void, ResponseModel> {
public AsyncResponseSendDivisionStocktakingItems delegate = null;
public SendDivisionStocktakingItemsService(AsyncResponseSendDivisionStocktakingItems delegate) {
this.delegate = delegate;
}
#Override
protected ResponseModel doInBackground(String... parameters) {
RequestHandler requestHandler = new RequestHandler();
JSONObject params = new JSONObject();
try {
params.put("stocktakingItems", parameters[1]);
} catch (JSONException e) {
e.printStackTrace();
}
ResponseModel responseModel = requestHandler.getRequestPostString(UHFApplication.getInstance().apiUrl
+ "/api/MobileService/SendDivisionStocktakingItemsPost?stocktakingID="
+ parameters[0],
parameters[1]);
return responseModel;
}
#Override
protected void onPreExecute() {
UpdateUI(send,total);
super.onPreExecute();
}
#Override
protected void onPostExecute(ResponseModel responseModel) {
super.onPostExecute(responseModel);
if (HttpURLConnection.HTTP_OK == responseModel.httpStatus) {
delegate.processFinish(true);
} else {
delegate.processFinish(false);
}
}
}
//UICalled method
public void UpdateUI(int send, int total) {
runOnUiThread(() -> {
progress.setMessage(send + "/" + total);
Log.d("Send Data : ", send + "/" + total);
if (send == total) {
progress.dismiss();
Toast.makeText(getApplicationContext(), "Succsess", Toast.LENGTH_SHORT).show();
}
});
}
//Update
//Ok I have a simle example how can I use. Below code when I click button I wan to open progress firstly and after that for loop is working and update progres message. I try it but not working.
Firstly For loop is working and after that progres opened.
public void ExportTry(){
UpdateUI(send,total);
runOnUiThread(new Runnable() {
#Override
public void run() {
btnExport.setEnabled(false);
progress.show();
}
});
for(int i=0;i<1000000;i++){
UpdateUI(i,1000000);
}
}

You are missing the part of AsyncTask that will allow you to show progress messages while doInBackground is running. Take a look at onProgressUpdate and publishProgress on the same page.
publishProgress
void publishProgress (Progress... values)
This method can be invoked from doInBackground(Params...) to publish updates on the UI thread while the background computation is still running. Each call to this method will trigger the execution of onProgressUpdate(Progress...) on the UI thread. onProgressUpdate(Progress...) will not be called if the task has been canceled.

Best approach to make a login screen

I am writing here because this is my last solution of understanding this type of programming.The problem is that I got stuck on what to use to handle the connection to a server and log-in. Should I use async task, handler or thread ? I didn't find a concrete answer stating which one to use, only found that async task is used to download images or other download stuffs.
Until now I have used a thread to connect to the server. The problem I encountered was when I catch the exception ( Putting invalid username/password ) and try to log-in again. ( I needed to "close" the last thread and start one again )
After this I started to use async task but I don't really understand how it should work and I am stuck on a toast of invalid username/password.
private class connectStorage extends AsyncTask<Void, Void, Void> {
#Override
protected Void doInBackground(Void... params) {
try {
api = DefaultClientFactory.create(host, getUser, getPassword);
if (api.getAuthToken().trim().length() > 3) {
//TO DO LAYOUT CHANGE;
}
} catch (StorageApiException e) {
e.printStackTrace();
Log.i("TEST", "" + e.getMessage());
}
return null;
}
Also, I am 100% sure that calling inflate in the doInBackground method won't work too ( there I wanted to change the activity ).
I am starting the async task on a button press.

When you are using asynctask
You have doInBackground and onPostExecute
So basically get a json or string or boolean as a result from doinbackground
and in onpostexecute check if the login in succesful or not if its succesful save the data from server and start an intent to go to another activity or toast the user that that user login details are wrong and try again.
So your asynctask can be an inner class of your activity class which is login and onClickSubmit button call the asynctask class and on post execute parse the json and according to the result decide what to do
Example:
public class SignInAsycTask extends AsyncTask<RequestParams, Void, String> {
#Override
protected String doInBackground(RequestParams... params) {
return new HttpManager().sendUserData(params[0]);
}
#Override
protected void onPostExecute(String result) {
String[] details = parseJsonObject(result);
if (details != null) {
user.setUser_id(Integer.valueOf(details[0]));
user.setName(details[1]);
if (details.length > 2) {
user.setProfilePic(details[2]);
}
setSharedPreferences();
startActivity(new Intent(Signin.this, MainActivity.class));
finish();
} else {
Toast.makeText(Signin.this, "please try again",
Toast.LENGTH_LONG).show();
}
}
}
public String[] parseJsonObject(String result) {
JSONObject obj = null;
try {
obj = new JSONObject(result);
if (obj.has("success")) {
if (obj.getInt("success") == 1) {
if (obj.has("user_pic")) {
return new String[] {
String.valueOf(obj.getInt("user_id")),
obj.getString("user_name"),
obj.getString("user_pic") };
} else {
return new String[] {
String.valueOf(obj.getInt("user_id")),
obj.getString("user_name"), };
}
} else {
return null;
}
} else {
return null;
}
} catch (JSONException e) {
e.printStackTrace();
return null;
}
}
here my RequestParams are just a object where I stored all the details like url parameters to send etc and the output of the doinbackground is a String and I am parsing it in my postexecute method

Queue-ing image paths for later upload

I'm having difficulties keeping track of my queue and uploading them at a later moment.
The upload image is a asynctask and in the postexecute a mail is going out to send the uploaded picture.
This is my UploadImage AsyncTask. I think i'm doing way too difficult and that it can be done much easier than it is right now.
private class UploadImageTask extends AsyncTask<Void, Void, Integer> {
ProgressDialog dialog;
/**
* Private integer which counts how many times we've tried to upload the
* Image.
*/
private int _counter = 0;
private List<String> imageUploadList = new ArrayList<String>();
#Override
protected void onPreExecute() {
super.onPreExecute();
if(AppStatus.haveNetworkConnection(_context)){
if(isPhotoTaken()){
dialog = new ProgressDialog(Step4.this);
dialog.setCancelable(false);
dialog.setProgressStyle(ProgressDialog.STYLE_SPINNER);
dialog.setMessage(getString(R.string.uploadingMessage));
dialog.setTitle(getString(R.string.uploadingTitle));
dialog.show();
}
}
}
protected Integer doInBackground(Void... params) {
init();
postData();
return null;
}
public void init(){
_counter = 0;
_beenHere = true;
for(String path : imageUploadList){
Debug.out("Path: "+path);
}
}
public void postData() {
if (isPhotoTaken()) {
if(AppStatus.haveNetworkConnection(_context)){
if(_beenHere){
ImageUploader.uploadFile(getPhotoPath(),
"http://obo.nl/android-upload-image.php", Step4.this);
} else {
for(String path : imageUploadList){
Debug.out(path);
ImageUploader.uploadFile(path,
"http://obo.nl/android-upload-image.php", Step4.this);
}
}
} else {
if (_counter == 0) {
_counter++;
_activity.runOnUiThread(new Runnable() {
public void run() {
Toast.makeText(_context,
getString(R.string.noInternetImageNotUploaded),
Toast.LENGTH_LONG).show();
}
});
imageUploadList.add(getPhotoPath());
}
try {
if(_beenHere){
_beenHere = false;
goToNextIntent();
}
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
postData();
}
}
}
private void goToNextIntent(){
Intent intent = new Intent(Step4.this, Step5.class);
intent.putExtra(EXTRA_MESSAGE, (Serializable) _user);
intent.putExtra(EXTRA_MESSAGE2, _isRepairable);
intent.putExtra(EXTRA_MESSAGE3, _injury);
intent.putExtra(EXTRA_MESSAGE4, _category);
intent.putExtra(EXTRA_MESSAGE5, _inch);
intent.putExtra(EXTRA_MESSAGE6, _size);
startActivity(intent);
}
protected void onPostExecute(Integer result) {
if(isPhotoTaken()){
if(dialog != null){
dialog.dismiss();
}
}
mailing(_isRepairable);
new MyAsyncTask().execute(_mail);
}
}
The line:
if(AppStatus.haveNetworkConnection(_context))
returns a boolean true if the user has a working internet connection. false otherwise.
What I want is to queue all the image paths (and mails sent afterwards) in the desired ArrayList so i can send them all at a later moment when the user has a working internet Connection. Please help me out!

You could store your image paths in a list (or something similar) and persist the list, let's say in Shared Preferences. As you finish uploading a picture, you will remove it from that list and continue to the next one, and so on until your list is empty.
While uploading, if the internet connection drops it will not affect you, you will always have persisted the list of images that are still to be uploaded.
Register a broadcast receiver to listen for wi-fi connection, when it gets connected it could automatically continue the upload - this is just a suggestion.

Performing data loading unitl succesfull or user break

In my app I performing loading data from web and then displaying it to user. Before loading data app shows progress dialog. I have problem if user locks phone in the middle of loading operation, or server is overloaded and can't respond in time my application freezes, because it doesn't dismiss progress dialog, or in some cases it crashes because lack on needed data.
If some error happened while loading data I want show some dialog to user to let him know about error and ask him should application repeat last request. I tried to use AlertDialog for it, but I haven't succeed.
Here is code of one activity (There is no progress dialog here, but it demonstrates how I loading data):
#EActivity(R.layout.layout_splash)
#RoboGuice
public class SplashScreenActivity extends Activity {
#Inject
private AvtopoiskParserImpl parser;
#Bean
BrandsAndRegionsHolder brandsAndRegionsHolder;
#ViewById(R.id.splash_progress)
ProgressBar progressBar;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
loadData();
}
#Background
protected void loadData() {
publishProgress(10);
LinkedHashMap<String, Integer> brands = null;
try {
brands = parser.getBrands();
} catch (IOException e) {
Log.e(e.getMessage());
}
publishProgress(50);
LinkedHashMap<String, Integer> regions = null;
try {
regions = parser.getRegions();
} catch (IOException e) {
Log.e(e.getMessage());
}
publishProgress(70);
populateData(brands, regions);
}
#UiThread
protected void populateData(LinkedHashMap<String, Integer> brands, LinkedHashMap<String, Integer> regions) {
Intent intent = new Intent(SplashScreenActivity.this, SearchActivity_.class);
brandsAndRegionsHolder.brandsMap = brands;
brandsAndRegionsHolder.regionsMap = regions;
publishProgress(100);
startActivity(intent);
finish();
}
#UiThread
void publishProgress(int progress) {
progressBar.setProgress(progress);
}
}
parser.getBrands() and parser.getRegions() are loading data from the web.
I want to do something like this:
boolean repeatRequest = true;
while (repeatRequest) {
try {
brands = parser.getBrands();
repeatRequest = false;
} catch (IOException e) {
Log.e(e.getMessage());
repeatRequest = showErrorDialog();
}
}
But I didn't manage to do so because this code executes in background thread, but dialog should be shown in UI thread.
I believe that it should be standard approach of doing so, but didn't manage to find it.
Any ides how can I implement this?

The best way is to use AsyncTask.
private class LoadDataTask extends AsyncTask<Void, Integer, Object> {
private ProgressDialog mProgress;
protected Object doInBackground(Void... params) {
// This method runs in background
Object result = null;
try {
result = parser.parse();
} catch (Exception e) {
result = e.getMessage();
}
return result;
}
protected void onProgressUpdate(Integer... progress) {
// This method runs in UI thread
mProgress.setProgress(progress[0]);
}
protected void onPreExecute() {
// This method runs in UI thread
mProgress = new ProgressDialog(context);
mProgress.show();
}
protected void onPostExecute(Object result) {
// This method runs in UI thread
mProgress.dismiss();
if (result instance of String) {
// Here you can launch AlertDialog with error message and proposal to retry
showErrorDialog((String) result);
} else {
populateData(result);
}
}
}