使用打开的DialogFragment旋转设备后,RecyclerView不会刷新

Question

我有一个RecyclerView内部AppCompatActivity.旋转设备后,会显示项目插入和更改并正确设置动画.

当你:

1. 点按中的项目RecyclerView.
2. 一DialogFragment,如果你想在删除的项目打开,提示.
3. 旋转设备.
4. 确认对话框中的删除.
5. 检查阵列列表.该项目已被删除.
6. 在RecyclerView仍显示该项目.

尝试使用notifyDataSetChanged而notifyItemRemoved不是工作,因为该项目仍在显示RecyclerView.

任何版本的Android都会发生这种情况.

有关如何处理流程的简化代码:

public class MyAppCompatActivity extends AppCompatActivity {
        int positionOfDeletedItem;
        MyObjectRecyclerViewAdapter adapter;
        ArrayList<MyObject> someTestData;
        MyItemDeletionHandler deletionHandlerRemover;

        public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.my_activity_layout);

            RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
            positionOfDeletedItem = 1;
            deletionHandlerRemover = new MyItemDeletionHandler(this);

            someTestData = new ArrayList<MyObject>(3);
            someTestData.add(new MyObject("A"));
            someTestData.add(new MyObject("B"));
            someTestData.add(new MyObject("C"));

            recyclerView.setHasFixedSize(true);
            recyclerView.setLayoutManager(new LinearLayoutManager(this));

            adapter = new MyObjectRecyclerViewAdapter(new MyAdapterOnClickEvent.OnItemClick() {
                @Override
                public void onClick(int posicion, int idViaje, View view) {
                    String tag = "Some tag value";
                    FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
                    Fragment prev = getSupportFragmentManager().findFragmentByTag(tag);
                    if(prev != null)
                        ft.remove(prev);
                    ft.addToBackStack(null);
                    DialogFragment newFragment = MyDeletionConfirmationDialog.newInstance(deletionHandlerRemover);
                    newFragment.show(ft, tag);
                }
            }, someTestData);
            recyclerView.setAdapter(adapter);
        }

        private final static class MyItemDeletionHandler extends Handler {
            private final WeakReference<MyAppCompatActivity> theActivity;

            private MyItemDeletionHandler(MyAppCompatActivity act) {
                theActivity = new WeakReference<MyAppCompatActivity>(act);
            }
            @Override
            public void handleMessage(Message msg) {
                MyAppCompatActivity activity = theActivity.get();
                if(activity != null) {
                    if(msg.what == 1) {
                        activity.deleteTheItem();
                    }
                }
            }
        }

        public void deleteTheItem() {
            someTestData.remove(positionOfDeletedItem);
            adapter.notifyItemRemoved(positionOfDeletedItem);
        }
}





public class MyDeletionConfirmationDialog extends DialogFragment {
    private Message handlerMessage;

    public static MyDeletionConfirmationDialog newInstance(Handler callbackHandler) {
        MyDeletionConfirmationDialog myDialog = new MyDeletionConfirmationDialog();

        Bundle args = new Bundle();
        args.putParcelable("handlerMessage", callbackHandler.obtainMessage(1, true));
        myDialog.setArguments(args);

        return myDialog;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        handlerMessage = getArguments().getParcelable("handlerMessage");
    }

    @Override
    @NonNull
    public Dialog onCreateDialog(Bundle savedInstanceState) {
        AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(getActivity());

        alertDialogBuilder.setMessage("Some message");
        alertDialogBuilder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialog, int id) {
                final Message toSend = Message.obtain(handlerMessage);
                toSend.sendToTarget();
            }
        });
        alertDialogBuilder.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
            }
        });
        Dialog dialog = alertDialogBuilder.create();
        dialog.setCanceledOnTouchOutside(true);
        return dialog;
    }
}

我怎样才能RecyclerView正常工作？

---

编辑1:

我有其他RecyclerViews正常工作.唯一的区别是那些是在Fragments 里面而不是AppCompatActivity.我怀疑这与事件onDetachedFromWindow和事件onAttachedToWindow有关RecyclerView.

---

编辑2:

如果对话框关闭(步骤4)并再次打开,则按预期工作.

---

编辑3:

如果RecyclerView提取Fragment问题,则问题消失并按预期工作.不可能将上述用例与上述用例结合使用AppCompatActivity而不是使用Fragment.

Answer 1

我在 RecyclerView 中也遇到了类似的问题。当我向左滑动删除某个项目然后旋转屏幕时，该项目已从我的数据集中删除，但屏幕并没有像我们在不旋转的情况下执行相同操作时那样刷新。看来 Adaptar.notifyItemRemoved() 根本没有刷新屏幕。

我使用Nemanja Kovacevic源代码作为起点，但我对其进行了一些更改（例如添加项目单击、使用对话框编辑、数据库支持等）。

所以我读了这篇文章，它给了我一个关于可能出现问题的提示。看来adapter.notify在轮换之前仍然指向先前的适配器引用。每次我们旋转时，都会在 Activity:OnCreate 中创建一个新适配器

public class MainActivity extends AppCompatActivity
    implements NavigationView.OnNavigationItemSelectedListener,
    AddAlertDialog.OnAlertSavedListener,
    AlertListAdapter.OnItemDeletedListener {

  static ListAdapter mListAdapter;
  RecyclerView mRecyclerView;
  ... 

  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    ...
    mRecyclerView = (RecyclerView) findViewById(R.id.mainListView);
    mDB = new DatabaseTable(this);

    // Reading all alerts
    ArrayList<Alert> alerts = mDB.getAllAlerts();

    if (mListAdapter == null)
        mListAdapter = new ListAdapter(this, alerts);
  }
}

也许它并不理想（创建静态对象不是一个好主意），但它解决了问题。

我希望它也可以帮助你。