Android how to runOnUiThread in other class?

See the article Communicating with the UI Thread.

With Context in hand, you can create a Handler in any class. Otherwise, you can call Looper.getMainLooper(), either way, you get the Main UI thread.

For example:

class CheckData{
    private final Handler handler;

    public Checkdata(Context context){
       handler = new Handler(context.getMainLooper());
    } 

    public void someMethod() {
       // Do work
       runOnUiThread(new Runnable() {
           @Override
           public void run() {
               // Code to run on UI thread
           }
       });
    }

    private void runOnUiThread(Runnable r) {
       handler.post(r);
    }  
}