我有一个主要活动,很多片段相互替换,并且状态总是迷路,我什至尝试过public void onSaveInstanceState(@NonNull Bundle outState)
,但仍然不起作用,我什至在MainActivity
中也做了保留实例,但一无所获
现在我有一个CartOrderFragment
,当单击按钮时,我会从FoodListFragment
向其中添加项目,但是每次我转到CartOrderFragment
并返回到FoodListFragment
并尝试通过单击同一按钮添加更多项目,CartOrderFragment
会丢失其列表。
MainActivity.java
public class MainActivity extends AppCompatActivity implements
SetupAccountFragment.SetupAccountListener, FoodListFragment.ListenerFoodListFragment,
SignInAccountFragment.SignInAccountListener, SignUpAccountFragment.SignUpAccountListener {
FragmentManager fm;
FoodListFragment foodListFragment;
ArrayList<Food> foodsOrdered;
CartOrdersFragment cartOrdersFragment;
Map<Integer, Integer> cartValues = new HashMap<>();
@Override
public void sendOrders(ArrayList<Food> foods) {
foodsOrdered = foods;
}
@Override
protected void onSaveInstanceState(@NonNull Bundle outState) {
super.onSaveInstanceState(outState);
getSupportFragmentManager().putFragment(outState, "myFragment", cartOrdersFragment);
}
// this get called when the button gets clicked in the FoodListFragment
@Override
public void cartClickListener() {
cartOrdersFragment = CartOrdersFragment.newInstance(foodsOrdered);
fm.beginTransaction()
.replace(R.id.main_container, cartOrdersFragment)
.addToBackStack(null)
.commit();
}
// for sign up fragment
@Override
public void registerNowBtnListener() {
foodListFragment = new FoodListFragment();
fm.beginTransaction()
.replace(R.id.main_container, foodListFragment)
.commit();
}
// for sign up fragment
// for sign in fragment
@Override
public void signInBtn() {
foodListFragment = new FoodListFragment();
fm.beginTransaction()
.replace(R.id.main_container, foodListFragment)
.commit();
}
// for sign in fragment
@Override
public void sendToCart(int value, int adapterPosition) {
cartValues.put(adapterPosition, value);
foodListFragment.updateCartValue(getTotalValue());
}
private int getTotalValue() {
int value = 0;
for (Integer key : cartValues.keySet()) {
value += cartValues.get(key);
}
return value;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (savedInstanceState != null) {
cartOrdersFragment = (CartOrdersFragment) getSupportFragmentManager().getFragment(savedInstanceState,
"myFragment");
}
fm = getSupportFragmentManager();
Fragment fragment = fm.findFragmentById(R.id.main_container);
if (fragment == null) {
// adding fragment to main container
fm.beginTransaction()
.replace(R.id.main_container, onBoardingFragment)
.replace(R.id.id_container_menu, new FoodCategoryFragment())
.addToBackStack(null)
.commit();
}
}
}
CartOrderFragment.java
public class CartOrdersFragment extends Fragment {
private CartOrdersAdapter cartOrdersAdapter;
private ArrayList<Food> foods;
private static final String KEY_ARRAYLIST = "ArrayList";
@Override
public void onSaveInstanceState(@NonNull Bundle outState) {
super.onSaveInstanceState(outState);
outState.putParcelableArrayList(KEY_ARRAYLIST, foods);
}
public static CartOrdersFragment newInstance(ArrayList<Food> foods) {
CartOrdersFragment cartOrdersFragment = new CartOrdersFragment();
Bundle args = new Bundle();
args.putParcelableArrayList(KEY_ARRAYLIST, foods);
cartOrdersFragment.setArguments(args);
return cartOrdersFragment;
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (savedInstanceState != null) {
foods = savedInstanceState.getParcelableArrayList(KEY_ARRAYLIST);
}
if (getArguments() != null) {
foods = getArguments().getParcelableArrayList(KEY_ARRAYLIST);
}
cartOrdersAdapter = new CartOrdersAdapter(getActivity(), foods);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(cartOrdersAdapter);
}
public class FoodListFragment extends Fragment {
private FoodListAdapter foodListAdapter;
private BadgeHolderLayout badgeHolderLayout;
private ArrayList<Food> foods;
public interface ListenerFoodListFragment {
void sendToCart(int value, int adapterPosition);
void cartClickListener();
void sendOrders(ArrayList<Food> foods);
}
private ListenerFoodListFragment listenerFoodListFragment;
@Override
public void onAttach(@NonNull Context context) {
super.onAttach(context);
try {
listenerFoodListFragment = (ListenerFoodListFragment) context;
} catch (ClassCastException e) {
Log.d("FoodListFragment", "onAttach: " + e.getMessage());
}
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
foods = new ArrayList<>();
foods.add(new Food("Chicken", "99999$", R.drawable.chicken));
foods.add(new Food("Burger", "1000$", R.drawable.burger));
badgeHolderLayout.setOnClickListener(v -> listenerFoodListFragment.cartClickListener());
foodListAdapter = new FoodListAdapter(getActivity(), foods, listenerFoodListFragment);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerView.setAdapter(foodListAdapter);
}
public void updateCartValue(int value) {
badgeHolderLayout.setCountWithAnimation(value);
}
}
FoodListAdapter.java
public class FoodListAdapter extends RecyclerView.Adapter<FoodListAdapter.ViewHolder>
implements Filterable {
private Context context;
private List<Food> foodList;
private List<Food> foodListFiltered;
private ArrayList<Food> orderedFood = new ArrayList<>();
FoodListFragment.ListenerFoodListFragment listenerFoodListFragment;
public FoodListAdapter(Context context, List<Food> foodList,
FoodListFragment.ListenerFoodListFragment listenerFoodListFragment) {
this.context = context;
this.foodList = foodList;
this.listenerFoodListFragment = listenerFoodListFragment;
this.foodListFiltered = foodList;
}
}
public class ViewHolder extends RecyclerView.ViewHolder {
public ViewHolder(@NonNull View itemView) {
super(itemView);
// this is the button that i mentioned
tvOk.setOnClickListener(v -> {
Food food = foodList.get(getAdapterPosition());
orderedFood.add(food);
listenerFoodListFragment.sendOrders(orderedFood);
});
fc.setOnClickListener(v -> fc.toggle(false));
}
}
}
答案 0 :(得分:1)
您可以使用隐藏和显示,试试这个
output_buffering = On