我试图使用 FragmentActivity 与 ViewPager 来显示片段动态列表。有很多例子就如何做一个静态的版本。我的问题是，在列表显示我需要动态加载的，也可以根据用户输入改变（添加/删除）。我试图使用自定义的 android.support.v4.content.Loader 来载入设置数据，我可以用它来建立我的名单。

I'm trying to use FragmentActivity with ViewPager to display dynamic list of Fragments. There are plenty of examples on how to do a static version of it. My problem is that the list I display needs to be loaded dynamically and also can change based on user input (add/delete). I'm trying to use customized android.support.v4.content.Loader to load set of data that I can use to build my list.

一切顺利在我的设置，直到我到这一点时，我想更新适配器及发行 FragmentStatePagerAdapter＃notifyDataSetChanged（）呼叫此时该code为执行（从 FragmentStatePagerAdapter ）

Everything goes fine in my setup until I get to the point when I want to update the adapter and issue FragmentStatePagerAdapter#notifyDataSetChanged() call at which point this code is executed (from FragmentStatePagerAdapter)

public void finishUpdate(View container)
{
    if(mCurTransaction != null)
    {
        mCurTransaction.commit(); // BANG!!! The exception is thrown
        mCurTransaction = null;
        mFragmentManager.executePendingTransactions();
    }
}

事务提交失败，此消息：

The transaction commit fails with this message:

java.lang.IllegalStateException：不能onLoadFinished内执行此操作

由于在 FragmentManagerImpl 这code执行：

because within FragmentManagerImpl this code is executed:

private void checkStateLoss() {
    if (mStateSaved) {
        throw new IllegalStateException(
                "Can not perform this action after onSaveInstanceState");
    }
    if (mNoTransactionsBecause != null) {
        throw new IllegalStateException(
                "Can not perform this action inside of " + mNoTransactionsBecause);
    }
}

原来， mNoTransactionsBecause 值不为空，它是在 LoaderManagerImpl.LoaderInfo 设置时，其结果是返回到 onLoadFinished

It turns out that mNoTransactionsBecause value is not null and it is set in LoaderManagerImpl.LoaderInfo when the result is returned back to onLoadFinished

我一直在寻找不同的变量试图以某种方式修改 tramsaction.commit（）到 transaction.commitAllowingStateLoss（）但有关的一切事务似乎是私人或至少包保护。

I was looking at the various variables trying to somehow change tramsaction.commit() to transaction.commitAllowingStateLoss() but everything related to transaction seems to be private or at least package-protected.

有人可以给我一个总的想法，如果我可以做我需要做的（以及如何）？

Can someone give me a general idea if I can do what I need to do (and how)?

只是要注意，我的code正常工作，而不是使用装载机当我运行负荷OPS中的AsyncTask

Just to note that my code works fine if instead of using Loader I run the loading ops in AsyncTask

推荐答案

我有一个非常类似的问题，这和使用上的片段的处理程序解决了这个问题。

I had a very similar problem to this and solved it by using a handler on the Fragment.

我想表现的onLoadFinished（），类似于以下

I wanted to show an alert dialog on onLoadFinished(), similar to the following

public class MyFragment extends Fragment 
    implements LoaderManager.LoaderCallbacks<T> {

    public void onLoadFinished(Loader<T> loader, T data) {
        showDialog();
    }

    public void showDialog() {
        MyAlertDialogFragment fragment = new MyAlertDialogFragment();
        fragment.show(getActivity().getSupportFragmentManager(), "dialog");

    }
}

但是，这给了一个错误

But this gave an error

不能onLoadFinished内执行此操作

解决的办法是添加一个处理程序片段拿显示该对话框的护理

The solution was to add a handler to the fragment to take care of showing the dialog

private Handler handler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        if(msg.what == MSG_SHOW_DIALOG) {
            showDialog();
        }
    }
};

然后修改onLoadFinished（...）将消息发送到处理程序，而不是

And then modify onLoadFinished(...) to send a message to the handler instead

   public void onLoadFinished(Loader<T> loader, T data) {
        handler.sendEmptyMessage(MSG_SHOW_DIALOG);
    }