@Override
            public void onClick(View v) {
                onBackPressed();
            }
to show use {@link AbsBoxingViewFragment} without {@link AbsBoxingActivity}.
use {@link Boxing#setupFragment(AbsBoxingViewFragment, Boxing.OnBoxingFinishListener)} to set a fragment.

@author ChenSL
app/src/main/java/com/bilibili/boxing/ui/SecondActivity.java