Android_ViewPager+Fragment实现页面滑动和底部导航栏

1、Xml中底部导航栏由一个RadioGroup组成，其上是ViewPager。

<?xml version="1.0" encoding="utf-8"?>

<RelativeLayout 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"

    android:orientation="horizontal"

    android:background="#FFFFFF"

    tools:context=".MainActivity">

    <LinearLayout

        android:id="@+id/main_toplinear"

        android:layout_width="match_parent"

        android:layout_height="70dp"

        android:background="@drawable/riple_btn_nocorner"

        android:gravity="center">

        <ImageView

            android:layout_width="60dp"

            android:layout_height="60dp"

            android:layout_margin="5dp"

            android:src="@drawable/icon"></ImageView>

        <TextView

            android:layout_width="wrap_content"

            android:layout_height="wrap_content"

            android:text="滴滴嗒小账本"

            android:textColor="#9E6E1E"

            android:textSize="25dp"></TextView>

    </LinearLayout>

    <View

        android:layout_width="match_parent"

        android:layout_height="0.5dp"

        android:layout_below="@+id/main_toplinear"

        android:background="#232"></View>

    <View

        android:layout_width="match_parent"

        android:layout_height="0.5dp"

        android:layout_above="@+id/main_radio_group"

        android:background="#232"></View>

    <RadioGroup

        android:id="@+id/main_radio_group"

        android:layout_width="match_parent"

        android:layout_height="70dp"

        android:layout_alignParentBottom="true"

        android:background="#EDDEF7"

        android:gravity="center"

        android:orientation="horizontal">

        <RadioButton

            android:layout_width="wrap_content"

            android:layout_height="match_parent"

            android:layout_weight="1"

            android:button="@null"

            android:text="记录"

            android:gravity="center"

            android:textSize="25dp"

            android:textColor="#9E6E1E"

            android:background="@drawable/radio"

            android:id="@+id/main_rd_cord"

            ></RadioButton>

        <RadioButton

            android:id="@+id/main_rd_inout"

            android:layout_width="5dp"

            android:layout_height="match_parent"

            android:layout_weight="1"

            android:gravity="center"

            android:textSize="25dp"

            android:textColor="#9E6E1E"

            android:text="收支"

            android:background="@drawable/radio"

            android:button="@null"></RadioButton>

        <RadioButton

            android:id="@+id/main_rd_my"

            android:layout_width="wrap_content"

            android:layout_height="match_parent"

            android:layout_weight="1"

            android:button="@null"

            android:gravity="center"

            android:textSize="25dp"

            android:textColor="#9E6E1E"

            android:background="@drawable/radio"

            android:text="我的"

            ></RadioButton>

    </RadioGroup>

    <androidx.viewpager.widget.ViewPager

        android:id="@+id/main_viewpager"

        android:layout_width="match_parent"

        android:layout_height="match_parent"

        android:layout_below="@+id/main_toplinear"

        android:layout_above="@id/main_radio_group"></androidx.viewpager.widget.ViewPager>

</RelativeLayout>

　　

2、编写几个页面的Fragment。

3、编写FragmentPagerAdapter，重写getItem和getCount方法。

package com.example.didida_corder;

import androidx.annotation.NonNull;

import androidx.fragment.app.Fragment;

import androidx.fragment.app.FragmentManager;

import androidx.fragment.app.FragmentPagerAdapter;

public class MyFragPageAdapter extends FragmentPagerAdapter {

    private int PAGE_NUM = 3;

    private final int PAGE_CORD = 0;

    private final int PAGE_INOUT = 1;

    private final int PAGE_MY = 2;

    private CordFragment cordFragment = null;

    private MyItemFragment myItemFragment = null;

    private InOutFragment inOutFragment = null;

    public MyFragPageAdapter(@NonNull FragmentManager fm) {

        super(fm);

        cordFragment = new CordFragment();

        myItemFragment = new MyItemFragment();

        inOutFragment = new InOutFragment();

    }

    @NonNull

    @Override

    public Fragment getItem(int position) {

        switch (position) {

            case PAGE_CORD: {

                return cordFragment;

            }

            case PAGE_INOUT: {

                return inOutFragment;

            }

            case PAGE_MY: {

                return myItemFragment;

            }

            default:

                return null;

        }

    }

    @Override

    public int getCount() {

        return PAGE_NUM;

    }

}

　　

4、在MainActivity中实现ViewPager.OnPageChangeListener和RadioGroup.OnCheckedChangeListener接口。

package com.example.didida_corder;

import androidx.appcompat.app.AppCompatActivity;

import androidx.viewpager.widget.ViewPager;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.widget.Adapter;

import android.widget.RadioButton;

import android.widget.RadioGroup;

import android.widget.TextView;

public class MainActivity extends AppCompatActivity implements ViewPager.OnPageChangeListener, RadioGroup.OnCheckedChangeListener{

    private MyFragPageAdapter myFragPageAdapter;

    private ViewPager viewPager;

    private TextView textView;

    private RadioGroup radioGroup;

    private RadioButton radioButton_crod;

    private RadioButton radioButton_inout;

    private RadioButton radioButton_myitem;

    private int PAGE_NUM = 3;

    private final int PAGE_CORD = 0;

    private final int PAGE_INOUT = 1;

    private final int PAGE_MY = 2;

    @Override

    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        myFragPageAdapter=new MyFragPageAdapter(getSupportFragmentManager());

        bindViews();

        radioButton_crod.setChecked(true);

    }

    private void bindViews(){

        radioButton_crod=findViewById(R.id.main_rd_cord);

        radioButton_inout=findViewById(R.id.main_rd_inout);

        radioButton_myitem=findViewById(R.id.main_rd_my);

        radioGroup=findViewById(R.id.main_radio_group);

        radioGroup.setOnCheckedChangeListener(this);

        viewPager= findViewById(R.id.main_viewpager);

        viewPager.setAdapter(myFragPageAdapter);

        viewPager.addOnPageChangeListener(this);

        viewPager.setCurrentItem(0);

    }

    @Override

    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {

    }

    @Override

    public void onPageSelected(int position) {

    }

    @Override

    public void onPageScrollStateChanged(int state) {

       if (state==2){

           switch (viewPager.getCurrentItem()){

               case PAGE_CORD:

                   radioButton_crod.setChecked(true);

                   break;

               case PAGE_INOUT:

                   radioButton_inout.setChecked(true);

                   break;

               case PAGE_MY:

                   radioButton_myitem.setChecked(true);

                   break;

           }

       }

    }

    @Override

    public void onCheckedChanged(RadioGroup group, int checkedId) {

        switch (checkedId){

            case R.id.main_rd_cord:{

                viewPager.setCurrentItem(PAGE_CORD);

                break;

            }

            case R.id.main_rd_inout:{

                viewPager.setCurrentItem(PAGE_INOUT);

                break;

            }

            case R.id.main_rd_my:{

                viewPager.setCurrentItem(PAGE_MY);

                break;

            }

        }

    }

}