public class ContinuousTask extends AsyncTask<String,String,String> {


    private Stack<Runnable> runnables = new Stack<>();
    private Runnable onFinish;

    @Override
    protected String doInBackground(String... params) {

        while(!runnables.isEmpty())
        {
            runnables.pop().run();
        }

        return null;
    }

    @Override
    protected void onPostExecute(String s) {
        super.onPostExecute(s);

        if(onFinish != null)
            onFinish.run();
    }

    public ContinuousTask then(Runnable runnable)
    {
        runnables.push(runnable);
        return this;
    }

    public ContinuousTask finish(Runnable runnable)
    {
        onFinish = runnable;
        return this;
    }
}

new ContinuousTask().then(new Runnable() {
            @Override
            public void run() {
              // codigo 1

            }
        }).then(new Runnable() {
            @Override
            public void run() {
              // codigo 2

            }
        }).then(new Runnable() {
            @Override
            public void run() {
              // codigo 3
            }
        }).finish(new Runnable() {
            @Override
            public void run() {
              // metodo final
            }
        }).runTasks();// se ejecuta los tasks