Develop Reference

Flag from AsyncTask class doesn't work properly in main class

I've created some lines of code which are supposed to switch to the next activity if connection is set without any exceptions. But if there are some exceptions, it should make "Error!" toast and not go to the next activity.
Boolean flag in Connection class works well: if the server is off, app will say "Error!", if on, it won't. But same flag in main class (con.flag) doesn't work properly, it looks like it is always false. App always switches to the next activity, with making toast or without, depending on server status. What's wrong in my code? I suppose that there's something I don't know about AsyncTask classes' fields initialization.
So, here is my code:
public class Connection extends AsyncTask<Void, Void, String> {
Context mContext;
public Connection(Context context){
this.mContext = context;
}
static String value;
boolean flag = false;
#Override
protected String doInBackground(Void... arg0) {
try {
Jedis jedis = new Jedis("192.168.0.120", 6381);
String name = jedis.ping();
value = name;
} catch (Exception e){
flag = true;
}
return null;
}
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (flag) {
Toast toast = Toast.makeText(mContext,
"Error!", Toast.LENGTH_LONG);
toast.show();
}
}
}
public class MainActivity extends AppCompatActivity {
Button click;
Context maincontext = this;
public void goTo2ndActivity(){
Intent intent = new Intent(this, Main2Activity.class);
startActivity(intent);
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
click = (Button)findViewById(R.id.button);
click.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final Connection con = new Connection(maincontext);
con.execute();
if (!con.flag){
goTo2ndActivity();
}
}
});
}
}

Your problem seems to be a race condition between main thread and the asynctask, the problem is in the onClick listener:
click.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final Connection con = new Connection(maincontext);
con.execute();
if (!con.flag){
goTo2ndActivity();
}
}
});
so this part
if (!con.flag){
goTo2ndActivity();
}
must be called from on post execute of your async task, for that pass the activity to the constructor of the async task like this:
update constructor of async task:
public class Connection extends AsyncTask<Void, Void, String> {
Context mContext;
MainActivity activity;
public Connection(Context context,MainActivity activity){
this.mContext = context;
this.activity= activity
}
..........
..........
and on post execute:
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (flag) {
Toast toast = Toast.makeText(mContext,
"Error!", Toast.LENGTH_LONG);
toast.show();
}else{
//go to next activity
activity.goTo2ndActivity();
}
}
now your button click becomes:
click.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//just execute
final Connection con = new Connection(maincontext,this);
con.execute();
}
});

How to add asyncTask code in application?

I have a register activity in my application. This has inputs of userid,email,password and mobile no. I have created an UI.
code:
public class RegisterActivity extends AppCompatActivity {
TextView already;
Button signUp;
RelativeLayout parent;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
parent = (RelativeLayout)findViewById(R.id.parentPanel);
setupUI(parent);
already = (TextView)findViewById(R.id.alreadyRegistered);
signUp = (Button) findViewById(R.id.sign_up_button);
already.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(RegisterActivity.this,LoginActivity.class));
}
});
signUp.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
startActivity(new Intent(RegisterActivity.this,LoginActivity.class));
}
});
}
public static void hideSoftKeyboard(Activity activity) {
InputMethodManager inputMethodManager = (InputMethodManager) activity.getSystemService(Activity.INPUT_METHOD_SERVICE);
inputMethodManager.hideSoftInputFromWindow(activity.getCurrentFocus().getWindowToken(), 0);
}
public void setupUI(View view) {
//Set up touch listener for non-text box views to hide keyboard.
if(!(view instanceof EditText)) {
view.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
hideSoftKeyboard(RegisterActivity.this);
return false;
}
});
}
//If a layout container, iterate over children and seed recursion.
if (view instanceof ViewGroup) {
for (int i = 0; i < ((ViewGroup) view).getChildCount(); i++) {
View innerView = ((ViewGroup) view).getChildAt(i);
setupUI(innerView);
}
}
}
}
Now I want to sync this UI with server.
For this I have a code of asyncTask created in another activity. How can I call this code or implement this code with UI?
AsyncTask code : RegisterActivity
public class RegisterActivity extends AppCompatActivity {
Context context;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
context = this;
RegisterAsyncTask task = new RegisterAsyncTask();
String userPhoto = "iVBORw0KGgoAAAANSUhEUgAAAEAAAABACAYAAACqaXHeAAAABHNCSVQICAgIfAhkiAAAAAlwSFlLBAIHAGdIMrN7hH1jKkmZz+d7MPu15md6PtCyrHmqvsgNVjY7Djh69OgwEaU1pkVwanKK0NLSsgvA8Vk=";
HashMap<String, String> params = new HashMap<String, String>();
params.put("userUsername", "user1");
params.put("userPassword", "user1");
params.put("gender", "M");
params.put("birthDate", "1986/7/12");
params.put("religion", "Hindu");
params.put("nationality", "Indian");
params.put("motherTongue", "Marathi");
params.put("birthPlace", "Pune");
params.put("userCountry", "India");
params.put("userState", "Maharashtra");
params.put("userCity", "Nashik");
params.put("userPincode", "422101");
params.put("userEmailid", "user1#gmail.com");
params.put("userMobileNo", "9696323252");
params.put("userPhoto", userPhoto);
}
public class RegisterAsyncTask extends AsyncTask<Map<String, String>, Void, JSONObject>{
#Override
protected JSONObject doInBackground(Map<String, String>... params) {
try {
String api = context.getResources().getString(R.string.server_url) + "api/user/register.php";
Map2JSON mjs = new Map2JSON();
JSONObject jsonParams = mjs.getJSON(params[0]);
ServerRequest request = new ServerRequest(api, jsonParams);
return request.sendRequest();
} catch(JSONException je) {
return Excpetion2JSON.getJSON(je);
}
}
#Override
protected void onPostExecute(JSONObject jsonObject) {
super.onPostExecute(jsonObject);
Log.d("ServerResponse", jsonObject.toString());
try {
int result = jsonObject.getInt("result");
String message = jsonObject.getString("message");
if ( result == 1 ) {
Toast.makeText(context, message, Toast.LENGTH_LONG).show();
//Code for having successful result for register api goes here
} else {
Toast.makeText(context, message, Toast.LENGTH_LONG).show();
//Code when api fails goes here
}
} catch(JSONException je) {
je.printStackTrace();
Toast.makeText(context, je.getMessage(), Toast.LENGTH_LONG).show();
}
}
}
}
How can I sync this? Please help. Thank you.
EDIT:
getEventsAsyncTask:
public class GetEventsAsyncTask extends AsyncTask<Void, Void, JSONObject> {
String api;
private Context context;
public GetEventsAsyncTask(Context context) {
this.context = context;
}
#Override
protected JSONObject doInBackground(Void... params) {
try {
api = context.getResources().getString(R.string.server_url) + "api/event/getEvents.php";
ServerRequest request = new ServerRequest(api);
return request.sendGetRequest();
} catch(Exception e) {
return Excpetion2JSON.getJSON(e);
}
} //end of doInBackground
#Override
protected void onPostExecute(JSONObject response) {
super.onPostExecute(response);
Log.e("ServerResponse", response.toString());
try {
int result = response.getInt("result");
String message = response.getString("message");
if (result == 1 ) {
Toast.makeText(context, message, Toast.LENGTH_LONG).show();
//code after getting profile details goes here
} else {
Toast.makeText(context, message, Toast.LENGTH_LONG).show();
//code after failed getting profile details goes here
}
} catch(JSONException je) {
je.printStackTrace();
Toast.makeText(context, je.getMessage(), Toast.LENGTH_LONG).show();
}
} //end of onPostExecute
}
dialog :
#Override
protected Dialog onCreateDialog(int id) {
Dialog dialog = null;
String[] listContent = {"Wedding",
"Anniversary",
"Naming Ceremony/Baptism",
"Thread Ceremony",
"Engagement",
"Birthday",
"Friends and Family Meet",
"Funeral",
"Movie",
"Play"};
switch(id) {
case CUSTOM_DIALOG_ID:
dialog = new Dialog(PlanEventActivity.this);
dialog.requestWindowFeature(Window.FEATURE_NO_TITLE);
dialog.setContentView(R.layout.choose_event_dialog);
dialog.setCancelable(true);
dialog.setCanceledOnTouchOutside(true);
dialog.setOnCancelListener(new DialogInterface.OnCancelListener(){
#Override
public void onCancel(DialogInterface dialog) {
// TODO Auto-generated method stub
}});
dialog.setOnDismissListener(new DialogInterface.OnDismissListener(){
#Override
public void onDismiss(DialogInterface dialog) {
// TODO Auto-generated method stub
}});
//Prepare ListView in dialog
dialog_ListView = (ListView)dialog.findViewById(R.id.dialoglist);
ArrayAdapter<String> adapter
= new ArrayAdapter<String>(this,
android.R.layout.simple_list_item_1, listContent);
dialog_ListView.setAdapter(adapter);
dialog_ListView.setOnItemClickListener(new AdapterView.OnItemClickListener(){
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
chooseEventText.setText(parent.getItemAtPosition(position).toString());
dismissDialog(CUSTOM_DIALOG_ID);
}});
break;
}
return dialog;
}
In this dialog want to show events from asyncTask. Thank you.

Not sure if i understand your question correctly, but to execute the AsyncTask, you just have to create an instance of RegisterAsyncTask and call the execute() method on it.
RegisterAsyncTask task = new RegisterAsyncTask();
task.execute(yourMap);
// you can pass multiple params to the execute() method
Or, if you don't need to get ahold of the instance:
new RegisterAsyncTask().execute(yourMap);

You can simply put your hashmap object, alongwith AsyncTask in your login activity code, and simply call AsyncTask in following manner.
HashMap<String, String> params = new HashMap<String, String>();
params.put("userUsername", "user1");
params.put("userPassword", "user1");
params.put("gender", "M");
params.put("birthDate", "1986/7/12");
params.put("religion", "Hindu");
params.put("nationality", "Indian");
params.put("motherTongue", "Marathi");
params.put("birthPlace", "Pune");
params.put("userCountry", "India");
params.put("userState", "Maharashtra");
params.put("userCity", "Nashik");
params.put("userPincode", "422101");
params.put("userEmailid", "user1#gmail.com");
params.put("userMobileNo", "9696323252");
params.put("userPhoto", userPhoto);
//call asynctask like this.
RegisterAsyncTask task = new RegisterAsyncTask();
task.execute(params);

Android Splash Screen AsyncTask

Basically I have a loading splash screen which will be executed when button was clicked:
public void onClick(View v) {
// Load the loading splash screen
Intent loadingIntent = new Intent(context, LoadingScreen.class);
context.startActivity(loadingIntent);
}
});
And in the LoadingScreen class:
public class LoadingScreen extends Activity{
//A ProgressDialog object
private ProgressDialog progressDialog;
/** Called when the activity is first created. */
#Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
//Initialize a LoadViewTask object and call the execute() method
new LoadViewTask().execute();
}
//To use the AsyncTask, it must be subclassed
private class LoadViewTask extends AsyncTask<Void, Integer, Void>
{
//Before running code in separate thread
#Override
protected void onPreExecute()
{
progressDialog = ProgressDialog.show(LoadingScreen.this,"Getting routes...",
"Loading data, please wait...", false, false);
}
//The code to be executed in a background thread.
#Override
protected Void doInBackground(Void... params)
{
try
{
//Get the current thread's token
synchronized (this)
{
//Initialize an integer (that will act as a counter) to zero
int counter = 0;
//While the counter is smaller than four
while(counter <= 4)
{
//Wait 850 milliseconds
this.wait(750);
//Increment the counter
counter++;
//Set the current progress.
//This value is going to be passed to the onProgressUpdate() method.
publishProgress(counter*25);
}
}
}
catch (InterruptedException e)
{
e.printStackTrace();
}
return null;
}
//Update the progress
#Override
protected void onProgressUpdate(Integer... values)
{
//set the current progress of the progress dialog
progressDialog.setProgress(values[0]);
}
//after executing the code in the thread
#Override
protected void onPostExecute(Void result)
{
finish();
//close the progress dialog
progressDialog.dismiss();
}
}
}
With these codes, the loading splash screen did came out. But I wonder is there any other way to show only the pop out dialogue for loading progress bar which on top on my previous screen?
Let's say my previous screen was event details. Then when user selected the button, only the dialogue box with loading progress bar will be shown instead of a new intent with a dialogue box.
Any ideas? Thanks in advance.
EDIT
public void onClick(View v) {
// Load the loading splash screen
new LoadViewTask().execute();
ENeighbourhoodActivity.tvDirection.setText("");
eventModel.setEventX(String.valueOf(eventModel.getEventX()));
eventModel.setEventY(String.valueOf(eventModel.getEventY()));
new GetEventDirectionAsyncTask(new GetEventDirectionAsyncTask.OnRoutineFinished() {
public void onFinish() {
//Hide the callout and plot user location marker
ENeighbourhoodActivity.callout.hide();
EventController.getUserLocation(context);
getActivity().finish();
}
}).execute(eventModel);
}
});
public class GetRegisteredEventAsyncTask extends
AsyncTask<String, Integer, Double> {
static EventController eventCtrl = new EventController();
public static ArrayList<Event> upcomingModel = new ArrayList<Event>();
public static ArrayList<Event> pastModel = new ArrayList<Event>();
public interface OnRoutineFinished { // interface
void onFinish();
}
private OnRoutineFinished mCallbacks;
public GetRegisteredEventAsyncTask(OnRoutineFinished callback) {
mCallbacks = callback;
}
public GetRegisteredEventAsyncTask() {
} // empty constructor to maintain compatibility
#Override
protected Double doInBackground(String... params) {
try {
upcomingModel = eventCtrl.getRegisteredUpcomingEvent(params[0]);
pastModel = eventCtrl.getRegisteredPastEvent(params[0]);
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Double result) {
if (mCallbacks != null)
mCallbacks.onFinish(); // call interface on finish
}
protected void onProgressUpdate(Integer... progress) {
}
}

In your onClick() method you could write something like:
new LoadViewTask().execute();
and the progress dialog will be shown in that page itself.

what are you doing man, just call your AsyncTask not the intent
public void onClick(View v)
{
new LoadViewTask().execute();
}
});
do your intent in postExecute
#Override
protected void onPostExecute(Void result)
{
finish();
//close the progress dialog
progressDialog.dismiss();
//START YOUR ACTIVITY HERE
Intent loadingIntent = new Intent(context, LoadingScreen.class);
context.startActivity(loadingIntent);
}
Must read the documentation of AsynTask

Java AsyncTask not showing progress on UI though publishProgress(progress)

In my android app, i am doing time consuming task extending AsyncTask, and want to display the progress in Toast messages. Toast messages are also displayed onPre() and onPost().
I am able to display Toast messages onPre() & onPost() but not able to show onProgressUpdate(Integer... progress).
Following is my code...
public class MainClass extends Activity {
public void Start(View view) {
DemoTasks runner = new DemoTasks(this);
runner.execute("Start");
}
private class DemoTasks extends AsyncTask<String, Integer, Integer> {
private Context context;
public DemoTasks(Context context){
this.context = context;
}
#Override
protected Integer doInBackground(String... params) {
try {
publishProgress(0);
doWork();
Thread.sleep(5000L);
publishProgress(100);
} catch (Exception localException) {
Log.d("POST", localException.getMessage());
}
return 100;
}
#Override
protected void onPostExecute(Integer result) {
Toast.makeText(context, "post", Toast.LENGTH_SHORT).show();
}
#Override
protected void onPreExecute() {
Toast.makeText(context, "pre", Toast.LENGTH_SHORT).show();
}
#Override
protected void onProgressUpdate(Integer... progress) {
super.onProgressUpdate(progress);
Toast.makeText(context, "progress-" + progress, Toast.LENGTH_SHORT).show();
}
}
}
Also in my doInBackgroud(String...params) ...Thread.sleep is also not working.
As soon as onPre() gets executed, onPost() also executes after that!!!!

You can try this,
showProgress ();
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
dialog.cancel();
Intent i=new Intent(getApplicationContext(),Main.class);
startActivity(i);
finish();
}
}, 3000); //number of seconds
private ProgressDialog dialog;
public void showProgress () {
dialog = new ProgressDialog(this);
dialog.setCancelable(true);
dialog.setMessage("Please wait");
dialog.show();}
Bascially,you can access the UI on any method, even In doinBackground you can access the UI using runOnUIthread.

here is one AsyncTask Example. This will show a peogress dialog while executing the task.
private class LoginProcessing extends AsyncTask<Object, Void, Void> {
private LoginCredentials myLoginCredentials;
private ProgressDialog progressDialog;
public LoginProcessing(LoginCredentials Credentials) {
super();
myLoginCredentials=Credentials;
progressDialog.setMax(100);
progressDialog.setMessage("Please Wait..");
progressDialog.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
progressDialog.setProgress(0);
progressDialog.show();
}
protected void onPreExecute (){
}
#Override
protected Void doInBackground(Object... arg0) {
// TODO Auto-generated method stub
//Code to do the process in background
return null;
}
#Override
protected void onProgressUpdate(Long... progress) {
// int percent = (int)(100.0*(double)progress[0]/mFileLen + 0.5);
progressDialog.setProgress(progress);
}
protected void onPostExecute(Void result){
progressDialog.dismiss();
//Your code after the process
}
}
You can call this Task as,
new LoginProcessing(loginCredentials).execute();
In this Example loginCredentials is the parameter I am passing to the AsyncTask. You can change it to your own parameter.

ProgressBar not showing up during a AsyncTask

I am trying to make a simple task in background and show a progress bar while it is being done.
This is the code for the main (and the only) Activity:
public class Login extends Activity {
public static ProgressDialog progressDialog;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
(...)
this.getWindow().requestFeature(Window.FEATURE_PROGRESS);
this.getWindow().setFeatureInt(Window.FEATURE_PROGRESS, Window.PROGRESS_VISIBILITY_ON);
progressDialog = new ProgressDialog(activity);
progressDialog.setMessage("Sending data...");
progressDialog.setCancelable(false);
(...)
// In some onClick Eevent..
JSONObject result = new Urltasks().execute(...).get();
(...)
}
}
This is the code for the activity:
class Urltasks extends AsyncTask<String, Integer, JSONObject>{
protected void onPreExecute() {
System.out.println("Inicia onPreExecute");
Login.progressDialog.show();
}
protected void onPostExecute(String result) {
Login.progressDialog.dismiss();
}
protected JSONObject doInBackground(String... arg0) {
// Some work being done. I do not use Login.progressDialog here
}
}
With this code the ProgressDialog shows up when the task ends, and it doesn't dismiss.

Problem is here:
JSONObject result = new Urltasks().execute(...).get();
Calling get() on an AsyncTask blocks the current thread, i.e. your UI thread, until the AsyncTask is executed. Therefore the progress dialog cannot run. Remove the get().
To obtain the result of the AsyncTask, you can e.g. pass in a listener callback to the asynctask that gets notified when the result is available:
class YourAsyncTask extends AsyncTask<ParamType, ProgressType, ResultType> {
private YourResultListener mListener;
interface YourResultListener {
void onResultAvailable(ResultType result);
}
YourAsyncTask(YourResultListener listener) {
mListener = listener;
}
#Override protected ResultType doInBackground(ParamType... params) {
//...
}
#Override protected void onPostExecute(ResultType result) {
mListener.onResultAvailable(result);
}
}
You can use it like:
mProgressDialog.show();
new YourAsyncTask(new YourResultListener() {
#Override void onResultAvailable(ResultType result) {
mProgressDialog.dismiss();
// use result
}).execute(params);
Personally I like to keep user interface elements such as progress dialogs decoupled from async tasks.

Don't put your progress dialog in your log in class. Keep it in the async task
this is how you show your dialog
progressDialog = ProgressDialog.show(yourActivityHERE.this, "",
"Loading... please wait.");
Edited this for you:
class Urls extends AsyncTask<String, Integer, JSONObject>{
ProgressDialog progressDialog;
protected void onPreExecute() {
progressDialog = ProgressDialog.show(yourActivityHERE.this, "",
"Loading... please wait.");
}
protected void onPostExecute(String result) {
progressDialog.dismiss();
}
protected JSONObject doInBackground(String... arg0) {
// Some work being done. I do not use Login.progressDialog here
}
}

create the constructor in your Urltasks sending the context of the calling class.
then use that context to create the progress dialog in the preExecute of your Urltasks
class Urltasks extends AsyncTask<String, Integer, JSONObject>{
Context mContext;
public static ProgressDialog progressDialog;
public UrlTasks(Context c){
mContext=c;
}
protected void onPreExecute() {
progressDialog = new ProgressDialog(mContext);
progressDialog.setMessage("Sending data...");
progressDialog.setCancelable(false);
progressDialog.show();
}
protected void onPostExecute(String result) {
progressDialog.dismiss();
}
protected JSONObject doInBackground(String... arg0) {
// Do your work here
}
}