问android底部栏在创建活动时设置默认选项卡

EN

 protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.thirdactivity);

        BottomBar bottomBar = BottomBar.attach(this, savedInstanceState);
        bottomBar.setItemsFromMenu(R.menu.bottom_menu, new OnMenuTabSelectedListener() {
            @Override
            public void onMenuItemSelected(int itemId) {
                 Intent myAct = new Intent();
            switch (itemId) {
                case R.id.item1:
                    myAct = new Intent(findViewById(itemId).getContext(), mainactivity.class);
                    break;
                case R.id.item2:
                    myAct = new Intent(findViewById(itemId).getContext(), secondactivity.class);
                    break;
                case R.id.item3:
                    myAct = new Intent(findViewById(itemId).getContext(), thirdactivity.class);
                    break;
            }
               startActivity(myAct);
            }
        });
    }