在可滑動選項卡中滑動動態添加的片段時，如何從viewpager中的片段中獲取數據？

Question

我正在開發一個包含購物功能且將商品添加到購物車的應用程序。 我有導航抽屜。 這樣，我將第一個片段稱為“ POSFragment”，其中我實現了一個viewpager作為數據，以可滑動選項卡的形式顯示。 數據將動態膨脹。 因此，我使用了PagerTabStrip和viewpager。 有一個稱為“ MenuDetailFragment”的通用片段，其中的數據將通過Web服務動態膨脹。 該片段的適配器是“ MenuPagerAdapter”。 現在，在此片段中，數據將顯示在列表視圖中。 在列表視圖的每一行中，可以使用每一行中的加號和減號按鈕來增加或減少項目。 在這些按鈕之間有textview，在此處將相應顯示數量。 我在兩個按鈕上都使用了Linkedhashmap，因此，項目和數量都保存在linkedhashmap中，然后保存在Sharedpreferences中。 到目前為止，一切正常。 當我在“查看”尋呼機中滑動時，出現下一個片段，並且當我單擊該項目上的增量按鈕或減量按鈕時，就會發生此問題。 在共享首選項中，它將開始保存當前片段項目，而以前的片段數據不再存在。 我已經使用過“ yourcustomviewpager.setOffscreenPageLimit（3）”，因此，我可以看到所選項目以及我來回滑動的數量，但是沒有使用Linkedhashmap存儲在sharedpreferences中的數據，而是保存了當前片段的數據。 我希望將新數據添加到以前的數據中，並且所有片段中的數據都應保留。 有辦法嗎？ 我已經面對這個問題很長時間了。 這是一些屏幕截圖和相關代碼段。

public class PosFragment extends Fragment {
private ViewPager viewPager;
View rootview;
String code;
String name;
String desc;
String rate;
String key;
Button viewCartBtn;
static TextView displayPrice;
static TextView noOfItemsInCart;
RippleView rippleView;
//private sendPosition pos;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
Log.e("oncreateview", "called");
// Inflate the layout for this fragment
rootview = inflater.inflate(R.layout.pos_fragment_layout, container, false);
initViews();
new AsyncTaskGetMenu().execute();
return rootview;
}
public void initViews() {
Log.e("init", "called");
viewPager = (ViewPager) rootview.findViewById(R.id.viewPager);
Button viewCartButton = (Button) rootview.findViewById(R.id.view_cart_btn);
viewPager.setOffscreenPageLimit(3);
viewCartBtn = (Button) rootview.findViewById(R.id.view_cart_btn);
AppMethods.setGlametrixBoldFont(getActivity(), viewCartBtn);
displayPrice = (TextView) rootview.findViewById(R.id.textView_totalprice_cart);
noOfItemsInCart = (TextView) rootview.findViewById(R.id.cart_items_quantity);
viewCartBtn.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(getActivity(), ViewCartActivity.class);
intent.putExtra(AppConstants.SUBTOTAL, Integer.parseInt(displayPrice.getText().toString()));
startActivity(intent);
}
});
LinearLayout itemsInCartLinearLayout = (LinearLayout) rootview.findViewById(R.id.ll_items_in_cart);
itemsInCartLinearLayout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(getActivity(), ViewCartActivity.class);
intent.putExtra(AppConstants.SUBTOTAL, Integer.parseInt(displayPrice.getText().toString()));
startActivity(intent);
}
});
}

---

This is "MenuDetailFragment" class
public class MenuDetailFragment extends Fragment {
View rootview;
private ListView listView;
private ArrayList<MenuHeadingDetailsModel> menuheadingDetailList;
private Communicate comm;
LinkedHashMap<String, ViewCartDetailsModel> viewCartDetailsModelMap = new LinkedHashMap<>();
ViewCartDetailsModel viewCartDetailsModel;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
// Inflate the layout for this fragment
rootview = inflater.inflate(R.layout.menu_list, container, false);
InitializeViews();
return rootview;
}
public void InitializeViews() {
listView = (ListView) rootview.findViewById(R.id.menu_items_list);
Bundle bundle = getArguments();
menuheadingDetailList = bundle.getParcelableArrayList(AppConstants.MENU_KEY);
listView.setAdapter(new MenuAdapter(getActivity(), menuheadingDetailList));[enter image description here][1]

---

這是“ MenuPagerAdapter”類

public class MenuPagerAdapter extends FragmentStatePagerAdapter {
List<MenuModel> menu;
public MenuPagerAdapter(FragmentManager fm, List<MenuModel> menuList) {
super(fm);
this.menu = menuList;
}
@Override
public CharSequence getPageTitle(int position) {
return menu.get(position).getHeading().toString();
}
private List<MenuHeadingDetailsModel> getMenuHeadingDetails(int pos) {
return this.menu.get(pos).getMenuHeadingDetailList();
}
@Override
public Fragment getItem(int position) {
Fragment fragment = new MenuDetailFragment();
Bundle bundle = new Bundle();
bundle.putParcelableArrayList(AppConstants.MENU_KEY, (ArrayList<? extends Parcelable>) getMenuHeadingDetails(position));
fragment.setArguments(bundle);
return fragment;
}
@Override
public int getCount() {
return menu.size();
}
@Override
public void unregisterDataSetObserver(DataSetObserver observer) {
if (observer == null) {
super.unregisterDataSetObserver(observer);
}
}
@Override
public void destroyItem (ViewGroup container, int position, Object object)
{
Log.e("destroyitem","called");
}
}
class MenuAdapter extends BaseAdapter {
//ViewHolder holder;
Context context;
List<MenuHeadingDetailsModel> myItems = new ArrayList<>();
Button buttonPlus, buttonMinus;
int totalAmount = 0;
int pagePosition;
public MenuAdapter(Context context, List<MenuHeadingDetailsModel> myItems) {
this.context = context;
this.myItems = myItems;
}
@Override
public int getCount() {
return myItems.size();
}
@Override
public Object getItem(int position) {
return myItems.get(position);
}
@Override
public long getItemId(int position) {
return 0;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
final ViewHolder viewHolder = new ViewHolder();
final LayoutInflater inflater = getActivity().getLayoutInflater();
convertView = inflater.inflate(R.layout.menu_list_item, null);
viewHolder.codeText = (TextView) convertView.findViewById(R.id.textView_code);
viewHolder.nameText = (TextView) convertView.findViewById(R.id.textView_name);
AppMethods.setGlametrixBoldFont(getActivity(), viewHolder.nameText);
viewHolder.descText = (TextView) convertView.findViewById(R.id.textView_desc);
viewHolder.rateText = (TextView) convertView.findViewById(R.id.textView_rate);
viewHolder.textViewNoOfItems = (TextView) convertView.findViewById(R.id.tv_no_of_items);
buttonMinus = (Button) convertView.findViewById(R.id.button_minus);
buttonPlus = (Button) convertView.findViewById(R.id.button_plus);
final MenuHeadingDetailsModel menu = myItems.get(position);
viewHolder.codeText.setText(menu.getCode());
viewHolder.nameText.setText(menu.getItemName());
viewHolder.descText.setText(menu.getDescription());
viewHolder.rateText.setText(menu.getRate());
viewHolder.textViewNoOfItems.setText("" + menu.getQuantity());
buttonPlus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
MenuHeadingDetailsModel menuList = myItems.get(position);
menuList.setQuantity(menuList.getQuantity() + 1);
myItems.set(position, menuList);
int itemRate = Integer.parseInt(myItems.get(position).getRate());
int itemQuan = menuList.getQuantity();
String code = menuList.getCode();
String name = menuList.getItemName();
int totalAmountPerItem = itemQuan * itemRate;
viewCartDetailsModel = new ViewCartDetailsModel(code, name, itemQuan, itemRate);
viewCartDetailsModelMap.put(viewCartDetailsModel.getCode(), viewCartDetailsModel);
Log.e("hashmap", "size" + viewCartDetailsModelMap.size());
Gson gson = new Gson();
String hashMapToString = gson.toJson(viewCartDetailsModelMap);
AppPreferences.saveDataInSharedpreferences(getActivity(), AppConstants.VIEW_ITEMS_INT_CART_KEY, hashMapToString);
totalAmount += itemRate;
int amount = totalAmount;
onButtonPressedForAmount(amount);
notifyDataSetChanged();
int quan = 0;
TextView tv;
for (int i = 0; i < listView.getCount(); i++) {
View view = listView.getAdapter().getView(i, null, null);
tv = (TextView) view.findViewById(R.id.tv_no_of_items);
quan = quan + Integer.parseInt(tv.getText().toString());
}
onButtonClickedForQuantity(quan);
}
}
);
buttonMinus.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
MenuHeadingDetailsModel menuList = myItems.get(position);
if ((menuList.getQuantity() - 1) >= 0) {
menuList.setQuantity(menuList.getQuantity() - 1);
myItems.set(position, menuList);
int itemRate = Integer.parseInt(myItems.get(position).getRate());
int itemQuan = menuList.getQuantity();
String code = menuList.getCode();
String name = menuList.getItemName();
//int totalAmountPerItem = itemQuan * itemRate;
viewCartDetailsModel = new ViewCartDetailsModel(code, name, itemQuan, itemRate);
if (itemQuan == 0) {
viewCartDetailsModelMap.remove(code);
} else {
viewCartDetailsModelMap.put(viewCartDetailsModel.getCode(), viewCartDetailsModel);
}
Gson gson = new Gson();
String hashMapToString = gson.toJson(viewCartDetailsModelMap);
AppPreferences.saveDataInSharedpreferences(getActivity(), AppConstants.VIEW_ITEMS_INT_CART_KEY, hashMapToString);
if (totalAmount > 0) {
totalAmount -= itemRate;
Log.e("totalamount", "minus" + totalAmount);
int amount = totalAmount;
onButtonPressedForAmount(amount);
}
} else {
menuList.setQuantity(0);
myItems.set(position, menuList);
}
notifyDataSetChanged();
int quan = 0;
TextView tv;
for (int i = 0; i < listView.getCount(); i++) {
View view = listView.getAdapter().getView(i, null, null);
tv = (TextView) view.findViewById(R.id.tv_no_of_items);
quan = quan + Integer.parseInt(tv.getText().toString());
}
onButtonClickedForQuantity(quan);
}
}
);
return convertView;
}
public void onButtonPressedForAmount(int userData) {
if (comm != null) {
comm.sendAmount(userData);
}
}
public void onButtonClickedForQuantity(int quantity) {
if (comm != null) {
comm.sendQuantity(quantity);
}
}
class ViewHolder {
TextView nameText;
TextView codeText;
TextView descText;
TextView rateText;
TextView textViewNoOfItems;
}
 }
//For settings fonts to the alert diaolog for customization of items
//public void setGlametrixBoldFont(TextView textView) {
//Typeface typeface = Typeface.createFromAsset(getActivity().getAssets(), "fonts/GlametrixBold.otf");
//textView.setTypeface(typeface);
// }
@Override
public void onAttach(Activity activity) {
super.onAttach(activity);
try {
comm = (Communicate) activity;
} catch (Exception e) {
AppMethods.getStackTrace(e);
}
}
public interface Communicate {
public void sendAmount(int amount);
public void sendQuantity(int quantity);
}
//    public void getPosition(int Position) {
//
//        int pagePosition = Position;
//        Log.e("pos", " " + pagePosition);
//    }
}

Answer 1

您可以通過以下方法在View頁面中獲取當前片段

SampleFragment sampleFr = (SampleFragment) viewPager.getAdapter().instantiateItem(viewPager, 0);

現在，您可以使用該片段訪問所需的任何數據。

第一次在視圖分頁器中添加片段的方式如下。

        BaseFragment frTimeLine = (BaseFragment) Fragment.instantiate(this, SampleFragment.class.getName());
        fragments.add(frTimeLine);
        BaseFragment frEarnTiqs = (BaseFragment) Fragment.instantiate(this, SampleFragment1.class.getName());
        fragments.add(frEarnTiqs);


        adapter = new ViewPagerAdapter(getSupportFragmentManager(), getResources(), fragments);
        viewPager.setAdapter(adapter);
        viewPager.setOffscreenPageLimit(3);