当用户旋转电话时保留列表视图项，并将所有数据保存在ArrayAdapter中

Question

我有一个具有Listview的应用程序，我通过按钮插入一个新行，但是当我旋转手机时，Listview内部的所有内容都消失了，我试图保留数据并重新创建Listview，但没有成功…数组userArray具有正确的数据，但是当我调用userAdapter.notifyDataSetChanged(); ListView未填充数据…

public class Page1 extends Fragment
{
    ListView userList;
        private ItemsListAdapter userAdapter=null;
        ArrayList<User> userArray = new ArrayList<User>();

        @Override
        public void onSaveInstanceState(Bundle outState) {
            Log.d(TAG, "onSaveInstanceState");
            super.onSaveInstanceState(outState);
            outState.putParcelableArrayList("key_userArray", userArray);
            outState.putParcelable("key_ListView", userList.onSaveInstanceState());
        }
        @Override
        public void onActivityCreated(Bundle savedInstanceState) {
            super.onActivityCreated(savedInstanceState);
            if (savedInstanceState != null) {
                // Restore last state.
                userArray = savedInstanceState.getParcelableArrayList("key_userArray");  
            }
        }    
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
            rootView = inflater.inflate(R.layout.page1, container, false);
            Log.d(TAG, "onCreateView");  
            appContext = getActivity().getBaseContext();
            appContextDialog = getActivity();
            GappContext = appContext.getApplicationContext();
            dBRicette = new ItemsSave();
            thisFrag = this;
            userList = null;
            userListIng = null;         
            //userAdapter = null;         
            userAdapterIng = null;
            myPref.loadPreference(appContext,MainActivity.DATABASE_INGR, MainActivity.ACCOUNT_PREFS_NAME);  
            init(rootView, savedInstanceState); 
            String myTag = getTag();        
            ((MainActivity)getActivity()).setTabFragPage1(myTag);
            int val = InitListaIngredienti();
            if(val == 0){
            }else
                Toast.makeText(getActivity().getBaseContext(), getResources().getString(R.string.msg_problem_db), Toast.LENGTH_LONG).show();
            return rootView;
        }
       void init(View rootView, Bundle savedInstanceState){
            if(userAdapter == null ){
                if(savedInstanceState == null || !savedInstanceState.containsKey("key_userArray")) {
                    userArray = new ArrayList<User>();
                    //userAdapter = new UserCustomAdapter(getActivity().getBaseContext(), R.layout.row, userArray);
                    userAdapter = new ItemsListAdapter(getActivity().getBaseContext(), userArray);
                    userList = (ListView) rootView.findViewById(R.id.listView);
                        userList.setItemsCanFocus(false);
                        userList.setClickable(true);
                        userList.setLongClickable(true);

                        userList.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
                            public boolean onItemLongClick(AdapterView<?> arg0, View v, int position, long id) {
                                // TODO Auto-generated method stub
                                RelativeLayout listItem = (RelativeLayout) v;
                                TextView clickedItemView = (TextView) listItem.findViewById(R.id.tv_prodotto);
                                String clickedItemString = clickedItemView.getText().toString();
                                Log.v(TAG,"DisplayListCustom LongClick detected " + clickedItemString + ", position " + Integer.toString(position));
                                if (currentActionMode != null) { 
                                    return false; 
                                }
                                currentListItemIndex = position;//(User)v.getTag();
                                currentActionMode = getActivity().startActionMode(modeCallBack);
                                v.setSelected(true);
                                return true;
                            }
                        }); 
                        //userList.setOnItemSelectedListener(this);
                        userAdapter.notifyDataSetChanged();
                        userList.setAdapter(userAdapter);  
                }else {
                    //recupero i valori
                    mListInstanceState = savedInstanceState.getParcelable("key_ListView");
                    userArray = savedInstanceState.getParcelableArrayList("key_userArray");
                    userAdapter = new ItemsListAdapter(getActivity().getBaseContext(), userArray);
                    userList = (ListView) rootView.findViewById(R.id.listView);
                    userList.onRestoreInstanceState(mListInstanceState);
                    userList.setAdapter(userAdapter);
//                  int size = userArray.size();
//                  for(int i = 0; i < size; i++){
//                      userAdapter.UpdateIng(userArray.get(i).qta, userArray.get(i).name, TotVar);
//                  }
                    userAdapter.notifyDataSetChanged();
                }
            }else        
                userAdapter.notifyDataSetChanged();   

class ItemsListAdapter extends BaseAdapter {
     private LayoutInflater vi;
     private ArrayList<User> data = new ArrayList<User>();
     Context context;
     User tmp = new User();
     NumberFormat numberFormat0  = new DecimalFormat("#0.0");
     public ItemsListAdapter(Context context, /*int layoutResourceId,*/ ArrayList<User> data) {
        super();
        vi = (LayoutInflater)context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        this.data = data;
        this.context = context;
     }
     /** Add white line */
     public void addItem(User item) {
        data.add(item);
         notifyDataSetChanged();
     }
     public ArrayList<User> getData() {
        return data;
    }
    public void setData(ArrayList<User> data) {
        this.data = data;
        notifyDataSetChanged();
    }
     @Override
     public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder = null;
         if (convertView == null) {
            holder = new ViewHolder();
            convertView = vi.inflate(R.layout.row3, parent, false);//null);
            holder.grid = (GridLayout) convertView.findViewById(R.id.GridLayout);
            holder.row = (TextView) convertView.findViewById(R.id.tv_row);
            holder.name = (TextView) convertView.findViewById(R.id.tv_prodotto);
            holder.quantity = (TextView) convertView.findViewById(R.id.tv_qta);
            holder.textPercT = (TextView) convertView.findViewById(R.id.tv_perc_T);
            holder.textPercZ = (TextView) convertView.findViewById(R.id.tv_perc_Z);
            holder.textPercG = (TextView) convertView.findViewById(R.id.tv_perc_G);
            holder.textUm = (TextView) convertView.findViewById(R.id.tv_grm);
            convertView.setTag(holder);
        }else {
            holder = (ViewHolder) convertView.getTag();
        }

Answer 1

这是因为onCreate在方向发生变化时被调用，有一个简单的方法可以停止调用onCreate。

只需在AndroidManifest.xml中添加configChanges属性，就像这样:

更多信息请参考以下文章

Activity restart on rotation Android

如何在Android上禁用方向改变?

http://developer.android.com/guide/topics/manifest/activity-element.html配置

Answer 2

这对onCreateView来说太多了。这个方法应该带着膨胀的视图尽快返回。当您旋转屏幕时，您应该简单地用在bundle中检索到的数据集重新创建适配器，重新创建适配器并在ListView的实例上再次调用setAdapter。活动使用onSavedInstanceState/onRestoreInstanceState对。如你所见，Fragment没有onRestoreInstancedState。你应该使用onActivityCreated来代替它