堆棧內存溢出
  簡體   English   中英

當我從活動中向后按下時，以及在底部導航欄中切換片段時，如何保留recyclerview滾動位置

[英]How can I retain recyclerview scroll position when i back pressed from activity to fragment and when switching fragments in bottom nav bar

 原文  2021-01-16 05:50:45  3   1    android/ android-recyclerview

問題描述

  1. 我將5個片段放置在帶有底部導航欄的主要活動中，這些片段具有回收站視圖，當我從底部導航欄切換時，先前的片段回收站視圖的滾動位置會自動重置為頂部，並且我想保留先前的滾動位置。

  2. 當我單擊碎片回收器視圖項目時，它進入活動狀態；當我從活動窗體中按下該鍵時，先前的碎片回收器視圖滾動位置重置為頂部，我也想保留它。

這是片段代碼

public class Assassin_Fragment extends Fragment {

    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    private String mParam1;
    private String mParam2;
    RecyclerView recyclerView;
    Ass_Adapter ass_adapter;
    FirebaseDatabase database;
    DatabaseReference reference;
    ProgressBar fpgbar;

    public Assassin_Fragment() {
    }

    public static Assassin_Fragment newInstance(String param1, String param2) {
        Assassin_Fragment fragment = new Assassin_Fragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_assassin_, container, false);

        recyclerView = (RecyclerView) view.findViewById(R.id.rcview);
        recyclerView.setLayoutManager(new GridLayoutManager(getContext(), 4));

        fpgbar = (ProgressBar) view.findViewById(R.id.fpgbar);

        FirebaseRecyclerOptions<Assassin_Models> options = new FirebaseRecyclerOptions.Builder<Assassin_Models>().setQuery(FirebaseDatabase.getInstance().getReference().child("Assassin"), Assassin_Models.class).build();

        ass_adapter = new Ass_Adapter(options, getContext());
        recyclerView.setAdapter(ass_adapter);

        reference = database.getInstance().getReference().child("Assassin");
        reference.keepSynced(true);

        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {
                if (snapshot.getChildrenCount() > 0) {
                    fpgbar.setVisibility(View.GONE);
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });

        return view;
    }

    @Override
    public void onStart() {
        super.onStart();
        ass_adapter.startListening();
    }

    @Override
    public void onStop() {
        super.onStop();
        ass_adapter.stopListening();
    }

    @Override
    public void onCreateOptionsMenu(@NonNull Menu menu, @NonNull MenuInflater inflater) {
        inflater.inflate(R.menu.about_us_menu, menu);
        MenuItem menuItem = menu.findItem(R.id.search);
        SearchView searchView = (SearchView) menuItem.getActionView();
        searchView.setInputType(InputType.TYPE_TEXT_FLAG_CAP_SENTENCES);
        searchView.setQueryHint("Search heros...");
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String s) {
                processsearch(s);
                return false;
            }

            @Override
            public boolean onQueryTextChange(String s) {
                processsearch(s);
                return false;
            }
        });
        super.onCreateOptionsMenu(menu, inflater);
    }

    private void processsearch(String s) {

        FirebaseRecyclerOptions<Assassin_Models> options = new FirebaseRecyclerOptions.Builder<Assassin_Models>().setQuery(FirebaseDatabase.getInstance().getReference().child("Assassin").orderByChild("heroname").startAt(s).endAt(s + "\uf8ff"), Assassin_Models.class).build();

        ass_adapter = new Ass_Adapter(options, getContext());
        ass_adapter.startListening();
        recyclerView.setAdapter(ass_adapter);

    }
}

這是底部導航代碼

 getSupportFragmentManager().beginTransaction().replace(R.id.container, new Herotablayout()).addToBackStack(null).commit();

    bottomNavigationView = findViewById(R.id.chipnav);

    integerDeque.push(R.id.champs);

    loadFragment(new Herotablayout());

    bottomNavigationView.setSelectedItemId(R.id.champs);

    bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            int id = item.getItemId();

            if (integerDeque.contains(id)) {

                if (id == R.id.champs) {
                    if (integerDeque.size() != 1) {

                        if (flag) {
                            integerDeque.addFirst(R.id.champs);

                            flag = false;
                        }
                    }
                }
                integerDeque.remove(id);
            }
            integerDeque.push(id);
            loadFragment(getFragment(item.getItemId()));
            return true;
        }
    });


}

private Fragment getFragment(int itemId) {
    switch (itemId) {
        case R.id.champs:
            bottomNavigationView.getMenu().getItem(0).setChecked(true);
            return new Herotablayout();

        case R.id.items:
            bottomNavigationView.getMenu().getItem(1).setChecked(true);
            return new Itemstablayout();

        case R.id.spells:
            bottomNavigationView.getMenu().getItem(2).setChecked(true);
            return new Spelltsablayout();

        case R.id.runes:
            bottomNavigationView.getMenu().getItem(3).setChecked(true);
            return new Runestablayout();

        case R.id.buffs:
            bottomNavigationView.getMenu().getItem(4).setChecked(true);
            return new Bufftablayout();

    }

    bottomNavigationView.getMenu().getItem(0).setChecked(true);
    return new Herotablayout();
}

private void loadFragment(Fragment fragment) {
    getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
}

幫幫我...如果可以的話，您可以用答案編輯我的代碼嗎，我是編程新手，謝謝

1 個解決方案

解決方案1
 0  2021-01-16 06:12:08

  1. 我將5個片段放置在帶有底部導航欄的主要活動中，這些片段具有回收站視圖，當我從底部導航欄切換時，先前的片段回收站視圖的滾動位置會自動重置為頂部，並且我想保留先前的滾動位置。

  2. 當我單擊碎片回收器視圖項目時，它進入活動狀態；當我從活動窗體中按下該鍵時，先前的碎片回收器視圖滾動位置重置為頂部，我也想保留它。

這是片段代碼

public class Assassin_Fragment extends Fragment {

    private static final String ARG_PARAM1 = "param1";
    private static final String ARG_PARAM2 = "param2";

    private String mParam1;
    private String mParam2;
    RecyclerView recyclerView;
    Ass_Adapter ass_adapter;
    FirebaseDatabase database;
    DatabaseReference reference;
    ProgressBar fpgbar;

    public Assassin_Fragment() {
    }

    public static Assassin_Fragment newInstance(String param1, String param2) {
        Assassin_Fragment fragment = new Assassin_Fragment();
        Bundle args = new Bundle();
        args.putString(ARG_PARAM1, param1);
        args.putString(ARG_PARAM2, param2);
        fragment.setArguments(args);
        return fragment;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setHasOptionsMenu(true);
        if (getArguments() != null) {
            mParam1 = getArguments().getString(ARG_PARAM1);
            mParam2 = getArguments().getString(ARG_PARAM2);
        }
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_assassin_, container, false);

        recyclerView = (RecyclerView) view.findViewById(R.id.rcview);
        recyclerView.setLayoutManager(new GridLayoutManager(getContext(), 4));

        fpgbar = (ProgressBar) view.findViewById(R.id.fpgbar);

        FirebaseRecyclerOptions<Assassin_Models> options = new FirebaseRecyclerOptions.Builder<Assassin_Models>().setQuery(FirebaseDatabase.getInstance().getReference().child("Assassin"), Assassin_Models.class).build();

        ass_adapter = new Ass_Adapter(options, getContext());
        recyclerView.setAdapter(ass_adapter);

        reference = database.getInstance().getReference().child("Assassin");
        reference.keepSynced(true);

        reference.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(@NonNull DataSnapshot snapshot) {
                if (snapshot.getChildrenCount() > 0) {
                    fpgbar.setVisibility(View.GONE);
                }
            }

            @Override
            public void onCancelled(@NonNull DatabaseError error) {

            }
        });

        return view;
    }

    @Override
    public void onStart() {
        super.onStart();
        ass_adapter.startListening();
    }

    @Override
    public void onStop() {
        super.onStop();
        ass_adapter.stopListening();
    }

    @Override
    public void onCreateOptionsMenu(@NonNull Menu menu, @NonNull MenuInflater inflater) {
        inflater.inflate(R.menu.about_us_menu, menu);
        MenuItem menuItem = menu.findItem(R.id.search);
        SearchView searchView = (SearchView) menuItem.getActionView();
        searchView.setInputType(InputType.TYPE_TEXT_FLAG_CAP_SENTENCES);
        searchView.setQueryHint("Search heros...");
        searchView.setOnQueryTextListener(new SearchView.OnQueryTextListener() {
            @Override
            public boolean onQueryTextSubmit(String s) {
                processsearch(s);
                return false;
            }

            @Override
            public boolean onQueryTextChange(String s) {
                processsearch(s);
                return false;
            }
        });
        super.onCreateOptionsMenu(menu, inflater);
    }

    private void processsearch(String s) {

        FirebaseRecyclerOptions<Assassin_Models> options = new FirebaseRecyclerOptions.Builder<Assassin_Models>().setQuery(FirebaseDatabase.getInstance().getReference().child("Assassin").orderByChild("heroname").startAt(s).endAt(s + "\uf8ff"), Assassin_Models.class).build();

        ass_adapter = new Ass_Adapter(options, getContext());
        ass_adapter.startListening();
        recyclerView.setAdapter(ass_adapter);

    }
}

這是底部導航代碼

 getSupportFragmentManager().beginTransaction().replace(R.id.container, new Herotablayout()).addToBackStack(null).commit();

    bottomNavigationView = findViewById(R.id.chipnav);

    integerDeque.push(R.id.champs);

    loadFragment(new Herotablayout());

    bottomNavigationView.setSelectedItemId(R.id.champs);

    bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
        @Override
        public boolean onNavigationItemSelected(@NonNull MenuItem item) {
            int id = item.getItemId();

            if (integerDeque.contains(id)) {

                if (id == R.id.champs) {
                    if (integerDeque.size() != 1) {

                        if (flag) {
                            integerDeque.addFirst(R.id.champs);

                            flag = false;
                        }
                    }
                }
                integerDeque.remove(id);
            }
            integerDeque.push(id);
            loadFragment(getFragment(item.getItemId()));
            return true;
        }
    });


}

private Fragment getFragment(int itemId) {
    switch (itemId) {
        case R.id.champs:
            bottomNavigationView.getMenu().getItem(0).setChecked(true);
            return new Herotablayout();

        case R.id.items:
            bottomNavigationView.getMenu().getItem(1).setChecked(true);
            return new Itemstablayout();

        case R.id.spells:
            bottomNavigationView.getMenu().getItem(2).setChecked(true);
            return new Spelltsablayout();

        case R.id.runes:
            bottomNavigationView.getMenu().getItem(3).setChecked(true);
            return new Runestablayout();

        case R.id.buffs:
            bottomNavigationView.getMenu().getItem(4).setChecked(true);
            return new Bufftablayout();

    }

    bottomNavigationView.getMenu().getItem(0).setChecked(true);
    return new Herotablayout();
}

private void loadFragment(Fragment fragment) {
    getSupportFragmentManager().beginTransaction().replace(R.id.container, fragment, fragment.getClass().getSimpleName()).addToBackStack(null).commit();
}

幫幫我...如果可以的話，您可以用答案編輯我的代碼嗎，我是編程新手，謝謝

暫無
暫無

聲明:本站的技術帖子網頁，遵循CC BY-SA 4.0協議，如果您需要轉載，請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.

相關問題 從其他活動返回到同一片段時，如何保存和恢復片段中 RecyclerView 的滾動位置？ 從片段反向按下時，recyclerview為空 按下后退按鈕時如何刷新片段？ 當我使用底部導航視圖時如何從主頁片段中的操作欄中刪除后退箭頭 從片段切換到活動並返回時沒有動畫 有什么方法可以在按下后保留 recyclerview 滾動條 position 如何在另一個活動的背面按下時保留 Recyclerview 的滾動位置，並從 firebase 實時數據庫中獲取數據？ 如何從片段中刪除主要活動的底部導航欄？ 從另一個活動返回活動時，RecyclerView 的滾動位置丟失 在操作欄選項卡/片段之間切換時如何保持狀態？
相關標簽
 
粵ICP備18138465號  © 2020-2024 STACKOOM.COM