how to execute code only after some asynchronous has finished executed?

Question

I am new in programming and in Android development. I have 3 asynchronous method to get data from server in my MainActivity, let say it is called

getUserDataFromServer()
getProductsDataFromServer()
getBannersFromServer()

if every request takes 1 second, then it needs 3 seconds to complete those 3 request If I chain it one after the other (in series).

so what I want is.... I want to make those 3 request asynchronously (in parallel) then if those 3 request has been done (either failed or success) then I want to do something else, let say to show up the Toast message. so I can finish it faster, maybe it just need around 1,2 s, not 3 s.

I don't know how to do it or what the special method called to wrap it in Android ?

how to do that in Java or Kotlin ?

Hey Alexa. This is actually not too difficult to do because there are many tutorials and articles explaining how to do it. Have you tried looking it up for yourself? Try checking out [this SO](https://stackoverflow.com/questions/9671546/asynctask-android-example) question. Or [this example from JournalDev](https://www.journaldev.com/9708/android-asynctask-example-tutorial) or [Android Developer's Documentation](https://developer.android.com/reference/android/os/AsyncTask). — Ishaan Javali, Jan 26 '19 at 00:37
ok, Thanks @IshaanJavali, I have tried to search but I don't know the right keyword , so maybe I need take time to learn about AsyncTask first I guess — Alexa289, Jan 26 '19 at 00:40
Yeah. The [Android Developer's](https://developer.android.com/reference/android/os/AsyncTask) documentation should definitely help you. — Ishaan Javali, Jan 26 '19 at 00:40

Ishaan Javali · Accepted Answer · 2019-01-26T00:53:31.097

The following code should help you get started for your purposes. It also has explanations of what is happening. You can change the parameters as required:

Executing the Task:

MyTask myTask = new MyTask();
myTask.execute(String1);

//OR:
new MyTask().execute(String1, String2, String3...);

Creating the Task:

//The first type in AsyncTask<> is for specifying the type of input given.
//Second parameter: Type of data to give to onProgressUpdate.
//Third parameter: Type of data to give to onPostExecute.
private class MyTask extends AsyncTask<String, String, String> {

    private String resp;
    ProgressDialog progressDialog;

    @Override
    protected String doInBackground(String... params) {
        publishProgress("Processing ..."); // Calls onProgressUpdate()
        //params is the input you've given that can be used for processing.

        getUserDataFromServer()
        getProductsDataFromServer()
        getBannersFromServer()

        //Result is the String to give onPostExecute when the task is done executing.
        String result = "Done Processing";
        return result;
    }

    @Override
    protected void onPostExecute(String result) {
        // Get the result from your task after it is done running.
        progressDialog.dismiss();
        //IMPORTANT: As you asked in your question, you can now execute whatever code you 
        //want since the task is done running.

    }

    @Override
    protected void onProgressUpdate(String... text) {
        //Progress has been updated. You can update the proggressDialog.       
    }
}

how to execute code only after some asynchronous has finished executed?

1 Answers1