What arguments are passed into AsyncTask arg1 arg2 arg3

Question

I don t understand what I am supposed to put in here and where these arguments end up  What exactly should I put  and where exactly will it go  Do I need to include all 3 or can I include 1 2 20

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Keep it simple  An AsyncTask is background task which runs in the background thread  It takes an Input  performs Progress and gives Output   ie AsyncTask lt Input Progress Output gt    In my opinion the main source of confusion comes when we try to memorize the parameters in the AsyncTask  The key is Don t memorize  If you can visualize what your task really needs to do then writing the AsyncTask with the correct signature would be a piece of cake  Just figure out what your Input  Progress and Output are and you will be good to go  For example   Heart of the AsyncTask  doInBackgound   method is the most important method in an AsyncTask because  Only this method runs in the background thread and publish data to UI thread  Its signature changes with the AsyncTask parameters    So lets see the relationship    doInBackground   and onPostExecute   onProgressUpdate   are also related   Show me the code So how will I write the code for DownloadTask  DownloadTask extends AsyncTask lt String Integer String gt           Override       public void onPreExecute                    Override       public String doInbackGround String    params                            Download code                int downloadPerc      calculate that                publish downloadPerc                   return  quot Download Success quot                   Override       public void onPostExecute String result                    super onPostExecute result                   Override       public void onProgressUpdate Integer    params                          show in spinner  access UI elements             How will you run this Task new DownLoadTask   execute  quot Paradise mp3 quot

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Google s Android Documentation Says that    An asynchronous task is defined by 3 generic types  called Params  Progress and Result  and 4 steps  called onPreExecute  doInBackground  onProgressUpdate and onPostExecute   AsyncTask s generic types     The three types used by an asynchronous task are the following   Params  the type of the parameters sent to the task upon execution  Progress  the type of the progress units published during the background computation  Result  the type of the result of the background computation    Not all types are always used by an asynchronous task  To mark a type as unused  simply use the type Void    private class MyTask extends AsyncTask lt Void  Void  Void gt            You Can further refer   http   developer android com reference android os AsyncTask html  Or You Can clear whats the role of AsyncTask by refering Sankar-Ganesh s Blog  Well The structure of a typical AsyncTask class goes like    private class MyTask extends AsyncTask lt X  Y  Z gt       protected void onPreExecute             This method is executed before starting the new Thread  There is no input output  values  so just initialize variables or whatever you think you need to do       protected Z doInBackground X   x            The most important method in the AsyncTask class  You have to place here all the stuff you want to do in the background  in a different thread from the main one  Here we have as an input value an array of objects from the type    X     Do you see in the header  We have       extends AsyncTask    These are the TYPES of the input parameters  and returns an object from the type    Z         protected void onProgressUpdate Y y           This method is called using the method publishProgress y  and it is usually used when you want to show any progress or information in the main screen  like a progress bar showing the progress of the operation you are doing in the background     protected void onPostExecute Z z          This method is called after the operation in the background is done  As an input parameter you will receive the output parameter of the doInBackground method   What about the X  Y and Z types   As you can deduce from the above structure    X     The type of the input variables value you want to set to the background process  This can be an array of objects    Y     The type of the objects you are going to enter in the onProgressUpdate method    Z     The type of the result from the operations you have done in the background process    How do we call this task from an outside class  Just with the following two lines   MyTask myTask   new MyTask     myTask execute x     Where x is the input parameter of the type X   Once we have our task running  we can find out its status from    outside     Using the    getStatus      method    myTask getStatus      and we can receive the following status   RUNNING - Indicates that the task is running   PENDING - Indicates that the task has not been executed yet   FINISHED - Indicates that onPostExecute Z  has finished   Hints about using AsyncTask   Do not call the methods onPreExecute  doInBackground and onPostExecute manually  This is automatically done by the system  You cannot call an AsyncTask inside another AsyncTask or Thread  The call of the method execute must be done in the UI Thread  The method onPostExecute is executed in the UI Thread  here you can call another AsyncTask    The input parameters of the task can be an Object array  this way you can put whatever objects and types you want

User · Answer

Refer to following links    http   developer android com reference android os AsyncTask html http   labs makemachine net 2010 05 android-asynctask-example    You cannot pass more than three arguments  if you want to pass only 1 argument then use void for the other two arguments   1  private class DownloadFilesTask extends AsyncTask lt URL  Integer  Long gt     2  protected class InitTask extends AsyncTask lt Context  Integer  Integer gt    An asynchronous task is defined by a computation that runs on a background thread and whose result is published on the UI thread  An asynchronous task is defined by 3 generic types  called Params  Progress and Result  and 4 steps  called onPreExecute  doInBackground  onProgressUpdate and onPostExecute   KPBird

User · Answer

in Short  There are 3 parameters in AsyncTask   parameters for Input use in DoInBackground String    params  parameters for show status of progress use in OnProgressUpdate String    status  parameters for result use in OnPostExcute String    result    Note   -  Type of parameters can vary depending on your requirement

User · Answer

I m too late to the party but thought this might help someone

[android] What arguments are passed into AsyncTask<arg1, arg2, arg3>?

Keep it simple!

Heart of the AsyncTask!

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