How can I call this following method in above java file?
In onCreateView(LayoutInflater, ViewGroup, Bundle) you can still use findViewById(int). The following will call the constructor you want:
java
View rootView = inflater.inflate(R.layout.fragment_budget_filter, container, false);
...
SeekBar seekBar = (SeekBar) rootView.findViewById(R.id.budget_max_seekbar);
TextView textView = (TextView) rootView.findViewById(R.id.max_budget);
AndroidSeekBar yourSeekBar = new AndroidSeekBar(seekBar, textView);
...
return rootView;