在动态 viewpager 片段中创建 recyclerviews
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【中文标题】在动态 viewpager 片段中创建 recyclerviews【英文标题】：Creating recyclerviews within dynamic viewpager fragments 【发布时间】：2020-12-27 09:02:08 【问题描述】：我的布局中有一个 tablayout+viewpager。
片段及其选项卡是从我的数据库中的类别动态创建的，因此当用户创建或删除新类别时它们会更新。
然后我希望能够在每个选项卡中将相应类别的项目显示为 recyclerview 项目。我已经在创建/编辑它们的常规 recyclerviews 的其他地方显示了这些项目，因此只需让它们在此 viewpager 中以相同的方式显示，按选项卡排序。项目也将使用日历视图按日期过滤。
到目前为止，我有一个 DynamicFragmentAdapter：
package com.example.navgraphtest;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentStatePagerAdapter;
import org.jetbrains.annotations.NotNull;
public class DynamicFragmentAdapter extends FragmentStatePagerAdapter
private int mNumOfTabs;
DynamicFragmentAdapter(FragmentManager fm, int NumOfTabs)
super(fm);
this.mNumOfTabs = NumOfTabs;
@NonNull
@Override
public Fragment getItem(int position)
Bundle b = new Bundle();
b.putInt("position", position);
Fragment frag = DynamicFragment.newInstance();
frag.setArguments(b);
return frag;
@Override
public int getCount()
return mNumOfTabs;
DynamicFragment 本身，目前只显示与其类别相关的索引
package com.example.navgraphtest;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import org.jetbrains.annotations.NotNull;
import java.util.ArrayList;
public class DynamicFragment extends Fragment
ArrayList<CategoryModel> arrayList;
public static DynamicFragment newInstance()
return new DynamicFragment();
@Override
public void onCreate(@Nullable Bundle savedInstanceState)
super.onCreate(savedInstanceState);
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState)
View view = inflater.inflate(R.layout.dynamic_fragment_layout, container, false);
initViews(view);
return view;
private void initViews(View view)
DatabaseHelper databaseHelper = new DatabaseHelper(getActivity());
arrayList = new ArrayList<CategoryModel>(databaseHelper.getCategories());
TextView textView=view.findViewById(R.id.commonTextView);
textView.setText(String.valueOf("Category : "+getArguments().getInt("position")));
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState)
super.onActivityCreated(savedInstanceState);
@Override
public void onAttach(@NotNull Context context)
super.onAttach(context);
@Override
public void onPause()
super.onPause();
@Override
public void onResume() super.onResume();
@Override
public void onStop()
super.onStop();
@Override
public void onDestroyView()
super.onDestroyView();
@Override
public void onDestroy()
super.onDestroy();
在主片段内
package com.example.navgraphtest;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.viewpager.widget.ViewPager;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import com.google.android.material.tabs.TabLayout;
import com.prolificinteractive.materialcalendarview.CalendarDay;
import com.prolificinteractive.materialcalendarview.MaterialCalendarView;
import com.prolificinteractive.materialcalendarview.OnDateSelectedListener;
import org.threeten.bp.LocalDate;
import java.util.ArrayList;
import static android.content.ContentValues.TAG;
public class CalendarViewFragment extends Fragment
private MaterialCalendarView mCalendarView;
private CalendarDay currentDate;
private TextView mTextViewCurrentDate;
private ViewPager mViewPager;
private TabLayout mTabLayout;
ArrayList<CategoryModel> arrayList;
@Override
public void onResume()
Log.d(TAG, "onResume: ");
super.onResume();
// Update ActionBar titles in MainActivity to reflect current fragment
// Actionbar is in main layout not the fragments.
((MainActivity) getActivity()).setActionBarTitle("Calendar View");
((MainActivity) getActivity()).getSupportActionBar().setSubtitle("View your consumption history");
// Open fragment with today's date selected on calendarview.
mCalendarView.setSelectedDate(CalendarDay.today());
// initViews for category tabs
initViews();
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
Log.d(TAG, "onCreateView: ");
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_calendar_view, container, false);
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState)
super.onViewCreated(view, savedInstanceState);
Log.d(TAG, "onViewCreated: ");
mTextViewCurrentDate = getActivity().findViewById(R.id.currentDateTextView);
mCalendarView = getActivity().findViewById(R.id.calendarView);
mCalendarView.setOnDateChangedListener(new OnDateSelectedListener()
@Override
public void onDateSelected(@NonNull MaterialCalendarView widget, @NonNull CalendarDay date, boolean selected)
mTextViewCurrentDate.setText(String.valueOf(date));
);
final NavController navController = Navigation.findNavController(view);
private void initViews()
Log.d(TAG, "initViews: ");
mViewPager = getActivity().findViewById(R.id.viewPagerCalendarView);
mTabLayout = getActivity().findViewById(R.id.tabLayoutCalendarView);
mViewPager.setOffscreenPageLimit(5);
mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(mTabLayout));
mTabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener()
@Override
public void onTabSelected(TabLayout.Tab tab)
mViewPager.setCurrentItem(tab.getPosition());
@Override
public void onTabUnselected(TabLayout.Tab tab)
@Override
public void onTabReselected(TabLayout.Tab tab)
);
setDynamicFragmentToTabLayout();
private void setDynamicFragmentToTabLayout()
DatabaseHelper databaseHelper = new DatabaseHelper(getActivity());
arrayList = new ArrayList<CategoryModel>(databaseHelper.getCategories());
Log.d(TAG, "setDynamicFragmentToTabLayout: ");
for (int i = 0; i < arrayList.size() ; i++)
mTabLayout.addTab(mTabLayout.newTab().setText(arrayList.get(i).getCategoryTitle()));
DynamicFragmentAdapter mDynamicFragmentAdapter = new DynamicFragmentAdapter(getActivity().getSupportFragmentManager(), mTabLayout.getTabCount());
mViewPager.setAdapter(mDynamicFragmentAdapter);
mViewPager.setCurrentItem(0);
我真的不知道如何实现这一点，没有取消用户创建类别的选项并且只有一个固定的数字，但是我不知道如何获得这些项目在 tablayout/viewpager 中显示。
【问题讨论】：
【参考方案1】：那么你的 dynamicFragmentAdapter 应该是这样的
public class DynamicFragmentAdapter extends FragmentStatePagerAdapter
private int mNumOfTabs;
Fragment fragment = null;
ViewPager viewPager;
ArrayList<Menu> fragDataList=new ArrayList<>();
private List<String> tabNameList;
Context context;
public DynamicFragmentAdapter (Context context,FragmentManager fm, int mNumOfTabs, List<String> tabNameList, ArrayList<Menu> fragDataList,ViewPager viewPager)
super(fm);
this.mNumOfTabs = mNumOfTabs;
this.tabNameList = tabNameList;
this.fragDataList=fragDataList;
this.context=context;
this.viewPager=viewPager;
@Override
public Fragment getItem(final int position)
for (int i = 0; i < mNumOfTabs ; i++)
fragment = GenericFragment.newInstance( fragDataList,position);
Log.i("info",String.valueOf(position));
break;
return fragment;
@Override
public int getCount()
return mNumOfTabs;
@Override
public CharSequence getPageTitle(int position)
return tabNameList.get(position);
// return super.getPageTitle(position);
你的主要片段通过你可以从数据库中获取数据，viewpager和tablayout会是这样的
//this method is used to set number of tabs dynamically
private void sendData(int /*sizeof tabNames list*/ size, final List<String> tabName, final ArrayList<Menu> fragArrayList, List<Menu> positioncheck)
Log.d("My Msg", "Tab countert check = " + size);
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener()
int pos = 0;
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels)
Bundle bundle = new Bundle();
bundle.putInt("position", position);
@Override
public void onPageSelected(int position)
pos = position;
@Override
public void onPageScrollStateChanged(int state)
);
final DynamicFragmentAdapter dynamicFragmentAdapter = new DynamicFragmentAdapter (getApplicationContext(), getSupportFragmentManager(), size, tabName, fragArrayList, viewPager);
viewPager.setAdapter(dynamicFragmentAdapter );
//viewPager.setOffscreenPageLimit(5);
// viewPager.setCurrentItem(tabLayout.getSelectedTabPosition());
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(new TabLayout.BaseOnTabSelectedListener()
@Override
public void onTabSelected(TabLayout.Tab tab)
viewPager.setCurrentItem(tab.getPosition());
@Override
public void onTabUnselected(TabLayout.Tab tab)
@Override
public void onTabReselected(TabLayout.Tab tab)
);
tabLayout.setupWithViewPager(viewPager);
你的 dynamicFragment 会得到数据
`public class DynamicFragment extends Fragment
static List<fragDAta> fragDataList;
static int loopsize = 0;
int mnum = 0;
public static DynamicFragment newInstance(ArrayList<fragData> fragDataList, int position)
DynamicFragment.fragDataList = fragDataList;
DynamicFragment f = new DynamicFragment ();
// Supply num input as an argument.
Bundle args = new Bundle();
args.putInt("position", position);
f.setArguments(args);
DynamicFragment.loopsize = loopsize;
return f;
public DynamicFragment ()
// Required empty public constructor
@Override
public void onCreate(@Nullable Bundle savedInstanceState)
super.onCreate(savedInstanceState);
mnum = getArguments() != null ? getArguments().getInt("position") : 1;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState)
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_dynamic, container, false);
@Override
public void setUserVisibleHint(boolean isVisibleToUser)
super.setUserVisibleHint(isVisibleToUser);
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState)
super.onViewCreated(view, savedInstanceState);
// here is your data
Log.d("MYMSG", "DATA CHECK = " + fragDataList.size());
@Override
public void onResume()
Log.d("MYMSG", "DATA CHECK = " + fragDataList.size());
super.onResume();
`
【讨论】：
您好，非常感谢您的回复。我已经尝试实施您的建议，但它不起作用。没有创建片段，也没有显示任何数据，只是带有标题的选项卡布局。 能否把代码分享给我，你是如何实现的，我可以看到并更准确地帮助你 抱歉回复晚了@Ifoste17 你得到结果了吗？如果没有，我会帮助你以上是关于在动态 viewpager 片段中创建 recyclerviews的主要内容，如果未能解决你的问题，请参考以下文章