ViewPager2 Demo详细写法

于 2022-01-05 13:45:35 发布
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本文链接：https://blog.youkuaiyun.com/CoderFucker/article/details/122321366
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前言:

ViewPager 2 底层是用 RecycleView 实现

Recyclerview需要编写adapter,VIewPager2同样也需要

使用前需要导入依赖

implementation 'androidx.viewpager2:viewpager2:1.0.0'
implementation 'androidx.recyclerview:recyclerview:1.1.0'

Demo1 最简单的水平翻页(垂直也可以)

1.像使用RecyclerView一样写一个adapter,完全一样,直接附上代码,不会写的可以先去简单学习以下Recyclerview

package com.example.viewpager2test.HorziontalTest;

import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.example.viewpager2test.R;

import java.util.List;

public class HorizontalVpAdapter extends RecyclerView.Adapter<HorizontalVpAdapter.ViewHolder> {

    List<Integer> backColorList;

    public HorizontalVpAdapter() {
    }

    public HorizontalVpAdapter(List<Integer> backColorList) {
        this.backColorList = backColorList;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_layout, parent,false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        int backColor = backColorList.get(position);
        holder.itemImage.setImageResource(backColor);

    }

    @Override
    public int getItemCount() {
        if (backColorList == null) {
            return 0;
        } else {
            return backColorList.size();
        }

    }

    class ViewHolder extends RecyclerView.ViewHolder {
        ViewGroup itemLayout;
        ImageView itemImage;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            itemImage = itemView.findViewById(R.id.item_image);
        }
    }
}

2.在xml中放上viewPager2控件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/my_view_pager2"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

    </androidx.viewpager2.widget.ViewPager2>

</LinearLayout>

3.在Activity中初始化

package com.example.viewpager2test.HorziontalTest;

import androidx.appcompat.app.AppCompatActivity;
import androidx.viewpager2.widget.ViewPager2;

import android.os.Bundle;

import com.example.viewpager2test.R;

import java.util.ArrayList;
import java.util.List;

public class HorizontalTestActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);
        ViewPager2 viewPager2 = this.findViewById(R.id.my_view_pager2);
        HorizontalVpAdapter horizontalVpAdapter = new HorizontalVpAdapter(initData());
        viewPager2.setAdapter(horizontalVpAdapter);
    }

    private List<Integer> initData() {
        List<Integer> backgrounds = new ArrayList<>();
        backgrounds = new ArrayList<>();
        backgrounds.add(android.R.color.holo_blue_bright);
        backgrounds.add(android.R.color.holo_red_dark);
        backgrounds.add(android.R.color.holo_green_dark);
        backgrounds.add(android.R.color.holo_orange_light);
        backgrounds.add(android.R.color.holo_purple);
        return backgrounds;
    }
}

打完收工,看看效果

横向滑动.gif

4.需要垂直翻页的只用加一句代码

public class HorizontalTestActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);
        ViewPager2 viewPager2 = this.findViewById(R.id.my_view_pager2);
        HorizontalVpAdapter horizontalVpAdapter = new HorizontalVpAdapter(initData());
        viewPager2.setAdapter(horizontalVpAdapter);

        //就加下面这一句就ok了,非常轻松
        viewPager2.setOrientation(ViewPager2.ORIENTATION_VERTICAL);
    }

    private List<Integer> initData() {
        List<Integer> backgrounds = new ArrayList<>();
        backgrounds = new ArrayList<>();
        backgrounds.add(android.R.color.holo_blue_bright);
        backgrounds.add(android.R.color.holo_red_dark);
        backgrounds.add(android.R.color.holo_green_dark);
        backgrounds.add(android.R.color.holo_orange_light);
        backgrounds.add(android.R.color.holo_purple);
        return backgrounds;
    }
}

Demo2 带Tab的翻页

1.先写布局xml,要放上tabLayout和ViewPager2

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    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=".MainActivity">

    <com.google.android.material.tabs.TabLayout
        android:id="@+id/tablayout"
        android:layout_width="0dp"
        android:layout_height="wrap_content"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <androidx.viewpager2.widget.ViewPager2
        android:id="@+id/viewpager2"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@id/tablayout" />

</androidx.constraintlayout.widget.ConstraintLayout>

2.用fragement

package com.example.viewpager2test.TabLayoutTest;

import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.FrameLayout;
import android.widget.RelativeLayout;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;

import com.example.viewpager2test.R;

import java.util.ArrayList;
import java.util.List;

public class PageFragment extends Fragment {
    private static final String COLORS = "colors";
    private static final String POSITION = "position";
    private List<Integer> mColors;
    private int mPosition;

    public static PageFragment newsInstance(List<Integer> colors, int position) {
        Bundle args = new Bundle();
        args.putSerializable(COLORS, (ArrayList<Integer>) colors);
        args.putInt(POSITION, position);
        PageFragment pageFragment = new PageFragment();
        pageFragment.setArguments(args);
        return pageFragment;
    }

    @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        if(getArguments()!=null){
            mColors=(List<Integer>)getArguments().getSerializable(COLORS);
            mPosition=this.getArguments().getInt(POSITION);
        }
    }

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.item_page, container, false);
        return view;
    }

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        RelativeLayout relativeLayout = view.findViewById(R.id.item_page_container);
        TextView textView = view.findViewById(R.id.item_page_tv);
        relativeLayout.setBackgroundResource(mColors.get(mPosition));
        textView.setText("Item"+mPosition);
    }
}

3.初始化

package com.example.viewpager2test.TabLayoutTest;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.fragment.app.FragmentManager;
import androidx.viewpager2.adapter.FragmentStateAdapter;
import androidx.viewpager2.widget.ViewPager2;

import android.os.Bundle;
import android.view.Menu;

import com.example.viewpager2test.R;
import com.google.android.material.tabs.TabLayout;

import java.util.ArrayList;
import java.util.List;

public class TabLayoutTestActivity extends AppCompatActivity {

    private ViewPager2 mViewPager2;
    private TabLayout mTabLayout;
    private List<Integer> colors = new ArrayList<>();
    private ViewPagerFragmentStateAdapter mViewPagerFragmentStateAdapter;

    {
        colors.add(android.R.color.black);
        colors.add(android.R.color.holo_purple);
        colors.add(android.R.color.holo_blue_dark);
        colors.add(android.R.color.holo_green_light);
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tab_layout_test);
        mTabLayout = findViewById(R.id.tablayout);
        mViewPager2 = findViewById(R.id.viewpager2);
        mViewPagerFragmentStateAdapter = new ViewPagerFragmentStateAdapter(this);
        mViewPager2.setAdapter(mViewPagerFragmentStateAdapter);
        mTabLayout.addTab(mTabLayout.newTab().setText("Tab0"));
        mTabLayout.addTab(mTabLayout.newTab().setText("Tab1"));
        mTabLayout.addTab(mTabLayout.newTab().setText("Tab2"));
        mTabLayout.addTab(mTabLayout.newTab().setText("Tab3"));
        mTabLayout.addOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
            @Override
            public void onTabSelected(TabLayout.Tab tab) {
                mViewPager2.setCurrentItem(tab.getPosition());
            }

            @Override
            public void onTabUnselected(TabLayout.Tab tab) {

            }

            @Override
            public void onTabReselected(TabLayout.Tab tab) {

            }
        });
        mViewPager2.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
            @Override
            public void onPageSelected(int position) {
                super.onPageSelected(position);
                mTabLayout.setScrollPosition(position, 0, false);
            }
        });
    }

    
    class ViewPagerFragmentStateAdapter extends FragmentStateAdapter {

        public ViewPagerFragmentStateAdapter(@NonNull FragmentActivity fragmentActivity) {
            super(fragmentActivity);
            if (colors == null) {
                colors = new ArrayList<>();
            }
        }

        @Override
        public int getItemCount() {
            return colors.size();
        }

        @NonNull
        @Override
        public Fragment createFragment(int position) {
            return PageFragment.newsInstance(colors, position);
        }
    }


}

4.在不同的tab放不同的fragment

比如我想在第二页放一个其他的fragment

class ViewPagerFragmentStateAdapter extends FragmentStateAdapter {

        public ViewPagerFragmentStateAdapter(@NonNull FragmentActivity fragmentActivity) {
            super(fragmentActivity);
            if (colors == null) {
                colors = new ArrayList<>();
            }
        }

        @Override
        public int getItemCount() {
            //控制viewPager2的页数 
            return colors.size();
        }

        @NonNull
        @Override
        public Fragment createFragment(int position) {
            //在这里控制你想在第几页放什么fragment
            if(position==1){
                return new NewPageFragment();
            }
            return PageFragment.newsInstance(colors, position);
        }
    }

Demo3 底部RadioGroup的ViewPager2

1.编写RadioTestActivity

package com.example.viewpager2test.RadioGroupTest;

import androidx.fragment.app.Fragment;
import androidx.viewpager2.widget.ViewPager2;

import android.os.Bundle;
import android.widget.RadioButton;
import android.widget.RadioGroup;

import com.example.viewpager2test.ForceOffline__Notification.BaseActivity;
import com.example.viewpager2test.R;
import com.example.viewpager2test.TabLayoutTest.NewPageFragment;

import java.util.ArrayList;
import java.util.List;

public class RadioTestActivity extends BaseActivity {
    private RadioGroup mRadioGroup;
    private ViewPager2 mViewPager2;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.radio_test_layout);
        mRadioGroup = this.findViewById(R.id.rg_vp);
        mViewPager2 = this.findViewById(R.id.vp_rg);
        RgAdapter rgAdapter = new RgAdapter(this);
        rgAdapter.setFragmentList(initData());
        mViewPager2.setAdapter(rgAdapter);
        
        //RadioGroup中的Radio check状态变化时的回调
        mRadioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                switch (checkedId) {
                    case R.id.rb_home:
                        mViewPager2.setCurrentItem(0);
                        break;
                    case R.id.rb_msg:
                        mViewPager2.setCurrentItem(1);
                        break;
                    case R.id.rg_my:
                        mViewPager2.setCurrentItem(2);
                        break;
                }
            }
        });

        //ViewPager2的当前页码变化时的回调
        mViewPager2.registerOnPageChangeCallback(new ViewPager2.OnPageChangeCallback() {
            @Override
            public void onPageSelected(int position) {
                super.onPageSelected(position);
                int childCount = mRadioGroup.getChildCount();
                for (int i = 0; i < childCount; i++) {
                    RadioButton radioButton = (RadioButton) mRadioGroup.getChildAt(i);
                    if (i == position) {
                        radioButton.setTextColor(getResources().getColor(R.color.colorPrimaryDark));
                    }else{
                        radioButton.setTextColor(getResources().getColor(R.color.colorAccent));
                    }
                }
            }
        });
    }

    // 不同的页显示不同的fragment，丰富viewPager2的内容
    private List<Fragment> initData() {
        List<Fragment> list = new ArrayList<>();
        list.add(NewPageFragment.getInstance());
        list.add(New2PageFragment.getInstance());
        list.add(New3PageFragment.getInstance());
        return list;
    }

}

2.编写ViewPager2的Adapter

package com.example.viewpager2test.RadioGroupTest;

import androidx.annotation.NonNull;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentActivity;
import androidx.viewpager2.adapter.FragmentStateAdapter;

import java.util.ArrayList;
import java.util.List;

public class RgAdapter extends FragmentStateAdapter {
    private List<Fragment> fragmentList;

    public RgAdapter(@NonNull FragmentActivity fragmentActivity) {
        super(fragmentActivity);
        if (fragmentList == null) {
            fragmentList = new ArrayList<>();
        }
    }

    public List<Fragment> getFragmentList() {
        return fragmentList;
    }

    public void setFragmentList(List<Fragment> fragmentList) {
        this.fragmentList = fragmentList;
    }

    @NonNull
    @Override
    public Fragment createFragment(int position) {
        return (Fragment) fragmentList.get(position);
    }

    @Override
    public int getItemCount() {
        return fragmentList.size();
    }
}

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