java.lang.IllegalStateException: No tab known for tag null

在开发中使用FragmentTabHost的时候，有时会报错

使用快捷键Ctrl+N，搜索这个类，

        // We are now ready to go. Make sure we are switched to the        // correct tab.        mAttached = true;//        ft = doTabChanged(currentTab, ft);        if (ft != null) {            ft.commit();            mFragmentManager.executePendingTransactions();        }    }

提前引用之后NulPoint了，注销掉就可以了……