Guys I can be the fastest man who solves his problem immediately after telling it in stackoverflow. The problem was: I deleted an overridden function when cleaning other stupid trying codes. I added it again into my main class:
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
Session.getActiveSession().onActivityResult(this, requestCode, resultCode, data);
}