How to Properly Override the onPostExecute() Method in an AsyncTask

Why is the onPostExecute() method not triggering in my AsyncTask implementation?

package com.asynctaskexample;

import android.os.AsyncTask;

public class AsyncTaskExampleActivity extends AsyncTask<Void, Void, Void> {

    AsyncTaskExampleActivity(){
        super();
    }

    @Override
    protected void onPreExecute() {
        // Initialization and setup can be done here
    }

    @Override
    protected Void doInBackground(Void... params) {
        // Background processing code
        return null;
    }

    @Override
    protected void onPostExecute(Void result) {
        // Code to be executed after background work is done
    }
}

The issue you’re experiencing with the onPostExecute() method in your AsyncTask class is common among Android developers. This typically happens when there is an incorrect method signature or an oversight in implementing the required parameters.

@Override
protected void onPostExecute(Void result) {
    // Tasks to execute once doInBackground is complete
}

Causes

• The onPostExecute() method must have the correct signature, including a parameter of type that matches the third type parameter of AsyncTask.
• For example, in your case, since your AsyncTaskExampleActivity class specifies Void as the return type for doInBackground, the onPostExecute method should also accept a Void parameter.

Solutions

• Correctly implement the onPostExecute() method with the matching parameter type: `protected void onPostExecute(Void result)`.
• Ensure you are calling execute() on your AsyncTask instance to trigger the execution process. Without it, onPreExecute, doInBackground, and onPostExecute will never run.

Mistake: Using incorrect method signature for onPostExecute()

Solution: The method signature for onPostExecute should match the third generic parameter of AsyncTask.

Mistake: Not calling the execute() method on the AsyncTask instance

Solution: Ensure to execute the AsyncTask instance to start the AsyncTask lifecycle.