if called Cancel or stop same function then start fresh if presently running in Android

Question

How do I within Android, if a function is called which is already running, cancel/stop that function then start it from the beginning?

My code looks like the below, basically throughout my application a given function( Important(); ) is called but rather than have that function run several times or prevent users from running the function again if presently running. I'd like to Cancel/stop the currently running function, then start it fresh?

How can I go about doing this?

Code:

public void Important() {
//Do lots of stuff
}

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Important();
    }

    @Override
    protected void onResume() {
        super.onResume();
    Important();
    }

I've already attempted the below making use of booleans. But it just stops a user from running the function again if already running? (which isn't what I'm trying to do)

I want, when the function is called again. The running function is stopped. Then freshly executed

Code:

Boolean runningCode = false;
    public void Important() {
if (runningCode== false) { 
runningCode = true;
    //Do lots of stuff
runningCode = false;
    }

FYI

Important() is called many times throughout my application ( in addition to the above ), sometimes whilst Important() is still running. Hence the need for a solution to my question :-)

Tasks like resetting variables and formatting the page are carried out within Important(); , it is not running on a separate thread. These are tasks that need to be completed on the main UI thread

Answer 1

You can use a Handler on the UI thread and post messages or Runnables to it. Make every discrete action in the Important() function be a message or Runnable containing a function (eg, resetVariables() , formatThePage() , etc). Whenever you call the function again, just call removeCallbacksAndMessages on the Handler and it will drop all actions that have not yet been executed.

Answer 2

Well, I don't understand why you want to do something like this?

There is not one simple answer to that. Probably working solution would be something like this

public void Important() {
if (runningCode == false) { 
    runningCode = true;
    //Do lots of stuff
    runningCode = false;
} else {
    // stop current code from execution
    runningCode = false;
    Important();
}

But you must figure your own code to stop current execution as it may result in broken state of objects etc...