Fragment already added 解决方式_fragment already added:-优快云博客

先判断Fragment有没有被添加（isAdded），但是仅仅有这个远远达不到我们需要的，还需要为这个Fragment加一个Tag，最后发现即使加了Tag还是不行，因为如果快速的点击两个Fragment切换页面,mFragmentManager().findFragmentByTag(这个方法返回来还是null。原因就是commit（）方法执行后并没有立即 add(mFragmentContainerId, fragment,Tag)，就造成
findFragmentByTag（xxx）读取不到内容。看一下commit的方法解释

Schedules a commit of this transaction. The commit does not happen immediately; it will be scheduled as work on the main thread to be done the next time that thread is ready.

最后解决方法是加上tag之后，还需要执行getSupportFragmentManager.executePendingTransactions()

总示例代码如下：


   FragmentTransaction transaction = mFragmentManager.beginTransaction();
   Fragment next = mFragmentList.get(position);
   if (next.isAdded() && mFragmentManager.findFragmentByTag(position + "") != null) {
       transaction.show(next);
   } else {
       mFragmentManager.executePendingTransactions();
       transaction.add(mFragmentContainerId, next, position + "");
       transaction.addToBackStack(null);
   }
   transaction.commitAllowingStateLoss();