相关视频教程在某站上面(🔍浩宇软件开发)

1. 开发环境

1. 开发工具：Androidstudio
2. 开发语言：Java
3. jdk版本：11+以上

2. 涉及到技术点

1. 底部导航栏控件BottomNavigationView的使用
2. BottomNavigationView的事件监听
3. Fragment在Activity中如何使用

3. 代码实现过程

1. 主页activity_main.xml布局

<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"
    tools:context=".MainActivity">


    <FrameLayout
        android:id="@+id/content"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_above="@id/bottomNavigationView" />


    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottomNavigationView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        app:itemIconTint="@color/my_light_primary"
        app:itemTextColor="@color/my_light_primary"
        app:labelVisibilityMode="selected"
        app:menu="@menu/navigation" />

</RelativeLayout>

2. 在res下新建menu文件夹，然后在menu中创建navigation.xml，如下图所示
   
   navigation.xml

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

    <item
        android:id="@+id/home"
        android:icon="@drawable/baseline_feed_24"
        android:title="首页" />


    <item
        android:id="@+id/search"
        android:icon="@drawable/baseline_manage_search_24"
        android:title="搜索" />


    <item
        android:id="@+id/mine"
        android:icon="@drawable/baseline_account_circle_24"
        android:title="我的" />
</menu>

3. 主页面MainActivity.java

底部导航栏页面之间的切换是Fragment，所以需要创建好三个fragment，HomeFragment，SearchFragment，MineFragment

public class MainActivity extends BaseActivity {
    private HomeFragment mHomeFragment;
    private SearchFragment mSearchFragment;
    private MineFragment mMineFragment;

    private BottomNavigationView mBottomNavigationView;

    @Override
    protected int getLayoutResId() {
        return R.layout.activity_main;
    }

    @Override
    protected void initViews() {

        mBottomNavigationView =findViewById(R.id.bottomNavigationView);

    }

    @Override
    protected void setListener() {


        mBottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                if (item.getItemId() ==R.id.home){
                    selectedFragment(0);
                }else if (item.getItemId() ==R.id.search){
                    selectedFragment(1);
                }else {
                    selectedFragment(2);
                }
                return true;
            }
        });

    }

    @Override
    protected void initData() {


        selectedFragment(0);

    }


    private void selectedFragment(int position) {

        FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
        hideFragment(fragmentTransaction);

        if (position == 0) {
            if (mHomeFragment == null) {
                mHomeFragment = new HomeFragment();
                fragmentTransaction.add(R.id.content, mHomeFragment);
            } else {
                fragmentTransaction.show(mHomeFragment);
            }
        } else if (position == 1) {
            if (mSearchFragment == null) {
                mSearchFragment = new SearchFragment();
                fragmentTransaction.add(R.id.content, mSearchFragment);
            } else {
                fragmentTransaction.show(mSearchFragment);

            }
        } else {
            if (mMineFragment == null) {
                mMineFragment = new MineFragment();
                fragmentTransaction.add(R.id.content, mMineFragment);
            } else {
                fragmentTransaction.show(mMineFragment);
            }
        }
        //一定要提交
        fragmentTransaction.commit();
    }

    private void hideFragment(FragmentTransaction fragmentTransaction) {

        if (mHomeFragment != null) {
            fragmentTransaction.hide(mHomeFragment);
        }
        if (mSearchFragment != null) {
            fragmentTransaction.hide(mSearchFragment);
        }
        if (mMineFragment != null) {
            fragmentTransaction.hide(mMineFragment);
        }

    }


}

4. 运行效果图

5. 教程教学

1. 视频教程：https://www.bilibili.com/video/BV1FJ4m1u76G/?spm_id_from=333.788&vd_source=984bb03f768809c7d33f20179343d8c8