本篇主要介绍一下 ViewPager2 + TabLayout + BottomNavigationView 的结合操作
概述
相信大家都看过今日头条的的样式 如下: 顶部有这种tab 并且是可以滑动的, 这就是本篇所介绍的 ViewPager2 + TabLayout 的组合 下面来看看如何实现把
实现思路
1.Activity 布局文件中引入BottomNavigationView 和 FragmentContainerView控件
2.编写 TabLayoutHomeFragment 布局文件
3.编写 Fragment 用于集成ViewPager2 和TabLayout
4. 编写 RecFragment 用于继承RecycleView 展示
5.实现 ViewPager2TabLayoutActivity
代码实现
1.Activity 布局文件中引入BottomNavigationView 和 FragmentContainerView控件
其中 menu 使用上一篇中的指定的 menu
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:andro
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ViewPager2TabLayoutActivity">
<androidx.fragment.app.FragmentContainerView
android:
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="@id/bootomnav3"/>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
app:menu="@menu/bottom_item_menu"
app:labelVisibilityMode="labeled"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
2.编写 TabLayoutHomeFragment 布局文件
主要想在这个 Home首页 Fragment 中 实现TabLayout 和 ViewPager2滑动功能
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:andro
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
tools:context=".tablayout.TabLayoutHomeFragment">
<com.google.android.material.tabs.TabLayout
android:
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="auto"
app:tabGravity="start"
app:tabBackground="@color/pink"
app:tabTextColor="@color/white"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toTopOf="@id/myviepage2"
/>
<androidx.viewpager2.widget.ViewPager2
android:
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintTop_toBottomOf="@id/mytablayout2"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
/>
</androidx.constraintlayout.widget.ConstraintLayout>
3. 编写 TabLayoutHomeFragment代码部分 用于集成ViewPager2 和TabLayout
package com.johnny.slzzing.tablayout;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.viewpager2.adapter.FragmentStateAdapter;
import androidx.viewpager2.widget.ViewPager2;
import com.google.android.material.tabs.TabLayout;
import com.google.android.material.tabs.TabLayoutMediator;
import com.johnny.slzzing.BottomFragment;
import com.johnny.slzzing.R;
import com.johnny.slzzing.RecFragment;
import java.util.Arrays;
import java.util.List;
public class TabLayoutHomeFragment2 extends Fragment {
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
private static final String TAG = "TabLayoutHomeFragment";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private ViewPager2 viewPager2;
private TabLayout tabLayout;
public TabLayoutHomeFragment2() {}
public static TabLayoutHomeFragment2 newInstance(String param1, String param2) {
TabLayoutHomeFragment2 fragment = new TabLayoutHomeFragment2();
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);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(
LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_tab_layout_home2, container, false);
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
viewPager2 = view.findViewById(R.id.myviepage2);
viewPager2.setSaveEnabled(false);
tabLayout = view.findViewById(R.id.mytablayout2);
List<String> titleList = initPageTitleList();
TabLayoutChildViewPager tabLayoutChildViewPager =
new TabLayoutChildViewPager(getActivity(),initChildFragmentList());
//重点!! ViewPager2绑定Adapter
viewPager2.setAdapter(tabLayoutChildViewPager);
//重点!! 关联 TabLayout 和 ViewPager2
new TabLayoutMediator(tabLayout, viewPager2, true,
(tab, position) -> tab.setText(titleList.get(position)))
.attach();
}
private List<String> initPageTitleList() {
return Arrays.asList("推荐","关注","娱乐","游戏","电影", "电视剧","实时新闻");
}
private List<Fragment> initChildFragmentList() {
//在tablayout 的第一个fragment 中使用 RecycleView 优化一下页面
RecFragment recFragment = new RecFragment();
//BottomFragment bottomFragment = BottomFragment.newInstance("推荐", "");
BottomFragment bottomFragment2 = BottomFragment.newInstance("关注", "");
BottomFragment bottomFragment3 = BottomFragment.newInstance("娱乐", "");
BottomFragment bottomFragment4 = BottomFragment.newInstance("游戏", "");
BottomFragment bottomFragment5 = BottomFragment.newInstance("电影", "");
BottomFragment bottomFragment6 = BottomFragment.newInstance("电视剧", "");
BottomFragment bottomFragment7 = BottomFragment.newInstance("实时新闻", "");
return Arrays.asList(
recFragment,
bottomFragment2,
bottomFragment3,
bottomFragment4,
bottomFragment5,
bottomFragment6,
bottomFragment7);
}
static class TabLayoutChildViewPager extends FragmentStateAdapter{
private List<Fragment> fragmentList;
public TabLayoutChildViewPager(@NonNull FragmentActivity fragmentActivity, List<Fragment> fragmentList) {
super(fragmentActivity);
this.fragmentList = fragmentList;
}
@NonNull
@Override
public Fragment createFragment(int position) {
return fragmentList.get(position);
}
@Override
public int getItemCount() {
return fragmentList.size();
}
}
}
4. 编写 RecFragment 用于继承RecycleView 展示
主要是优化TabLayout 的第一个fragment 样式
package com.johnny.slzzing;
import static com.johnny.slzzing.R.drawable.discountberry;
import static com.johnny.slzzing.R.drawable.discountbrocoli;
import static com.johnny.slzzing.R.drawable.discountmeat;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import java.util.ArrayList;
import java.util.List;
/**
* A simple {@link Fragment} subclass.
* Use the {@link RecFragment#newInstance} factory method to
* create an instance of this fragment.
*/
public class RecFragment extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
private RecyclerView discountRecyclerView;
private DiscountedProductAdapter discountedProductAdapter;
public RecFragment() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* @param param1 Parameter 1.
* @param param2 Parameter 2.
* @return A new instance of fragment RecFragment.
*/
// TODO: Rename and change types and number of parameters
public static RecFragment newInstance(String param1, String param2) {
RecFragment fragment = new RecFragment();
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);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_rec, container, false);
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
discountRecyclerView = view.findViewById(R.id.discountedRecycler);
setDiscountedRecycler(initDiscountList());
}
private List<DiscountedProducts> initDiscountList() {
List<DiscountedProducts> discountedProductsList = new ArrayList<>();
discountedProductsList.add(new DiscountedProducts(1, discountberry, "草莓", "草莓，多年生草本植物。高10-40厘米，茎低于叶或近相等，密被开展黄色柔毛"));
discountedProductsList.add(new DiscountedProducts(2, discountbrocoli, "花菜","花椰菜（是十字花科、芸薹属植物野甘蓝的变种。"));
discountedProductsList.add(new DiscountedProducts(3, discountmeat, "西红柿", "番茄 是茄科茄属 [2] 一年生或多年生草本植物，体高0.6-2米，全体生粘质腺毛，有强烈气味，茎易倒伏，叶羽状复叶或羽状深裂"));
discountedProductsList.add(new DiscountedProducts(4, discountberry, "西瓜","西瓜 一年生蔓生藤本；茎、枝粗壮，具明显的棱。卷须较粗壮，具短柔毛，叶柄粗，密被柔毛"));
discountedProductsList.add(new DiscountedProducts(5, discountbrocoli, "南瓜","南瓜 葫芦科南瓜属的一个种，一年生蔓生草本植物"));
discountedProductsList.add(new DiscountedProducts(6, discountmeat, "猕猴桃", "中华猕猴桃 是猕猴桃科、猕猴桃属大植物。大型落叶藤本；幼一枝或厚或薄地被有灰白色茸毛或褐色长硬毛或铁锈色硬毛状刺毛，老时秃净或留有断损残毛"));
discountedProductsList.add(new DiscountedProducts(7, discountberry, "草莓", "草莓，多年生草本植物。高10-40厘米，茎低于叶或近相等，密被开展黄色柔毛"));
discountedProductsList.add(new DiscountedProducts(8, discountbrocoli, "花菜","花椰菜 是十字花科、芸薹属植物野甘蓝的变种。"));
discountedProductsList.add(new DiscountedProducts(9, discountmeat, "西红柿", "番茄 是茄科茄属 [2] 一年生或多年生草本植物，体高0.6-2米，全体生粘质腺毛，有强烈气味，茎易倒伏，叶羽状复叶或羽状深裂"));
discountedProductsList.add(new DiscountedProducts(10, discountberry, "西瓜","西瓜 一年生蔓生藤本；茎、枝粗壮，具明显的棱。卷须较粗壮，具短柔毛，叶柄粗，密被柔毛"));
discountedProductsList.add(new DiscountedProducts(11, discountbrocoli, "南瓜","南瓜 葫芦科南瓜属的一个种，一年生蔓生草本植物"));
discountedProductsList.add(new DiscountedProducts(12, discountmeat, "猕猴桃", "中华猕猴桃 是猕猴桃科、猕猴桃属大植物。大型落叶藤本；幼一枝或厚或薄地被有灰白色茸毛或褐色长硬毛或铁锈色硬毛状刺毛，老时秃净或留有断损残毛"));
return discountedProductsList ;
}
private void setDiscountedRecycler(List<DiscountedProducts> dataList) {
RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(getContext(), LinearLayoutManager.VERTICAL, false);
discountedProductAdapter = new DiscountedProductAdapter(getContext(),dataList);
discountRecyclerView.setLayoutManager(layoutManager);
discountRecyclerView.setAdapter(discountedProductAdapter);
}
}
5.实现 ViewPager2TabLayoutActivity
package com.johnny.slzzing;
import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.MenuItem;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentContainerView;
import com.google.android.material.bottomnavigation.BottomNavigationView;
import com.google.android.material.navigation.NavigationBarView;
import com.johnny.slzzing.tablayout.TabLayoutHomeFragment2;
import java.util.HashMap;
import java.util.Map;
public class ViewPager2TabLayoutActivity extends AppCompatActivity {
BottomNavigationView bottomNavigationView;
FragmentContainerView fragmentContainerView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_view_pager2_tab_layout);
bottomNavigationView = findViewById(R.id.bootomnav3);
fragmentContainerView = findViewById(R.id.container_view);
Map<Integer, Fragment> fragmentMap = new HashMap<>();
TabLayoutHomeFragment2 tabLayoutHomeFragment2 = new TabLayoutHomeFragment2();
//这里 第一个home fragment 使用上面编写的 TabLayoutHomeFragment2
fragmentMap.put(R.id.home_item,tabLayoutHomeFragment2);
fragmentMap.put(R.id.type_item,Bottom2Fragment.newInstance("我是typefragment", ""));
fragmentMap.put(R.id.add_item,Bottom2Fragment.newInstance("我是addfragment", ""));
fragmentMap.put(R.id.setting_item,Bottom2Fragment.newInstance("我是settingfragment", ""));
//bottomNavigationView 点击用于替换 FragmentContainerView
bottomNavigationView.setOnItemSelectedListener(new NavigationBarView.OnItemSelectedListener() {
@SuppressLint("NonConstantResourceId")
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
int itemId = item.getItemId();
switch (itemId){
case R.id.home_item:
getSupportFragmentManager().beginTransaction()
.replace(R.id.container_view, fragmentMap.get(R.id.home_item))
.commit();
break;
case R.id.type_item:
getSupportFragmentManager().beginTransaction()
.replace(R.id.container_view, fragmentMap.get(R.id.type_item))
.commit();
case R.id.add_item:
getSupportFragmentManager().beginTransaction()
.replace(R.id.container_view, fragmentMap.get(R.id.add_item))
.commit();
case R.id.setting_item:
getSupportFragmentManager().beginTransaction()
.replace(R.id.container_view, fragmentMap.get(R.id.setting_item))
.commit();
}
return true;
}
});
getSupportFragmentManager().beginTransaction()
.replace(R.id.container_view, fragmentMap.get(R.id.home_item))
.commit();
}
}
效果
可以看到 顶部有类似 今日头条的 Tab 并且可以滑动哟
总结
本篇主要介绍了 ViewPager2 + TabLayout 的一个集成 实现类似今日头条的顶部Tab 并且支持滑动
核心联动代码
不同于ViewPager , ViewPager2 使用 TabLayoutMediator 来联动TabLayout 和ViewPager2 以及 tab的标题,注意最后要 attach()
viewPager2.setAdapter(tabLayoutChildViewPager);
new TabLayoutMediator(tabLayout, viewPager2, true,
(tab, position) -> tab.setText(titleList.get(position)))
.attach();
欢迎大家访问 个人博客 Johnny小屋
欢迎关注个人公众号
