安卓Fragment与ViewPager设置app底部导航

package cn.aisencode.www.adapter;

import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import java.util.List;

/**
 * 
文件描述：

 * 
作者：Aisen

 * 
创建时间：2021.2.7 15:07

 * 
博客地址：www.aisencode.cn

 */
public class ViewPagerAdapter extends FragmentPagerAdapter {
    private List fragments;
    public ViewPagerAdapter(FragmentManager fm, List fragments) {
        super(fm);
        this.fragments = fragments;
    }

    @Override
    public Fragment getItem(int position) {
        return fragments.get(position);
    }

    @Override
    public int getCount() {
        return fragments.size();
    }
}

package cn.aisencode.www.fragment;

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

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

import cn.aisencode.www.R;

/**
 * 
文件描述：

 * 
作者：Aisen

 * 
创建时间：2021.2.7 14:37

 * 
博客地址：www.aisencode.cn

 */
public class HomeFragment extends Fragment{
    private View view;
    private TextView textView;

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        //第一个参数是子布局，第二个参数是要加载进去的父布局，第三个是否将载入的视图绑定到根视图中
        view = inflater.inflate(R.layout.layout_fragment,container,false);
        textView = view.findViewById(R.id.textView);
        textView.setText(R.string.home);
        return view;
    }
}

package cn.aisencode.www;

import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.viewpager.widget.ViewPager;

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

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

import cn.aisencode.www.adapter.ViewPagerAdapter;
import cn.aisencode.www.fragment.DynamicFragment;
import cn.aisencode.www.fragment.HomeFragment;
import cn.aisencode.www.fragment.MineFragment;

public class MainActivity extends AppCompatActivity {
    private ViewPager viewPager;
    private ViewPagerAdapter viewPagerAdapter;
    private List fragments;
    private HomeFragment homeFragment = new HomeFragment();
    private DynamicFragment dynamicFragment = new DynamicFragment();
    private MineFragment mineFragment = new MineFragment();
    private RadioGroup radioGroup;
    private RadioButton raioHome,radioDynamic,radioMine;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        viewPager = findViewById(R.id.viewPager);
        radioGroup = findViewById(R.id.radio_group);
        raioHome = findViewById(R.id.radio_home);
        radioDynamic = findViewById(R.id.radio_dynamic);
        radioMine = findViewById(R.id.radio_mine);
        //创建fragments的list
        fragments = new ArrayList<>();
        fragments.add(homeFragment);
        fragments.add(dynamicFragment);
        fragments.add(mineFragment);
        //viewPager绑定adapter
        FragmentManager fragmentManager = getSupportFragmentManager();
        viewPagerAdapter = new ViewPagerAdapter(fragmentManager,fragments);
        viewPager.setAdapter(viewPagerAdapter);
        //viewPager，radioGroup，初始化选中
        viewPager.setCurrentItem(0);
        radioGroup.check(R.id.radio_home);

        //设置viewPager的Listener中的onPageSelected与radioGroup绑定
        viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
            @Override
            public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

            }


            @Override
            public void onPageSelected(int position) {
                switch (position){
                    case 0:
                        radioGroup.check(R.id.radio_home);
                        break;
                    case 1:
                        radioGroup.check(R.id.radio_dynamic);
                        break;
                    case 2:
                        radioGroup.check(R.id.radio_mine);
                        break;
                }
            }

            @Override
            public void onPageScrollStateChanged(int state) {

            }
        });
        //radioGroup设置Listener与viewPager绑定
        radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
            @Override
            public void onCheckedChanged(RadioGroup group, int checkedId) {
                switch (checkedId){
                    case R.id.radio_home:
                        viewPager.setCurrentItem(0);
                        break;
                    case R.id.radio_dynamic:
                        viewPager.setCurrentItem(1);
                        break;
                    case R.id.radio_mine:
                        viewPager.setCurrentItem(2);
                        break;
                }
            }
        });
    }
}

<?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"
    android:orientation="vertical">
    <androidx.viewpager.widget.ViewPager
        android:id="@+id/viewPager"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_weight="1"/>
    <View
        android:layout_width="match_parent"
        android:layout_height="0.5dp"
        android:background="@color/gray"/>
    <RadioGroup
        android:id="@+id/radio_group"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:orientation="horizontal">
        <RadioButton
            android:id="@+id/radio_home"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:button="@null"
            android:text="@string/home"
            android:gravity="center"
            android:checked="true"
            android:textColor="@drawable/text_selector"
            android:background="@null"/>
        <RadioButton
            android:id="@+id/radio_dynamic"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:button="@null"
            android:text="@string/dynamic"
            android:gravity="center"
            android:textColor="@drawable/text_selector"
            android:background="@drawable/button_selector"/>
        <RadioButton
            android:id="@+id/radio_mine"
            android:layout_width="0dp"
            android:layout_height="match_parent"
            android:layout_weight="1"
            android:button="@null"
            android:text="@string/mine"
            android:gravity="center"
            android:textColor="@drawable/text_selector"/>
    </RadioGroup>

</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<ripple xmlns:android="http://schemas.android.com/apk/res/android"
android:color="@color/gray"> <!--波纹颜色-->
<item>
<shape android:shape="rectangle">
<!-- 填充背景色-->
<solid android:color="@color/white"/>
</shape>
</item>
</ripple>

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <!-- 单击时的背景颜色 -->
    <item
        android:drawable="@color/gray"
        android:state_pressed="true">
    </item>
    <!-- 未单击时的背景颜色 -->
    <item
        android:drawable="@color/white"
        android:state_pressed="false">
    </item>
</selector>

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:color="@color/pink"
        android:state_checked="true" />
    <item android:color="@color/gray"
        android:state_checked="false" />
</selector>