2024最新最简单的安卓底部菜单栏教程

大界面跳转

public class MainActivity extends AppCompatActivity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);BottomNavigationView bot = findViewById(R.id.bottomNavigationView);getSupportFragmentManager().beginTransaction().replace(R.id.linearLayout,new IndexFragment()).commit();
//       getSupportFragmentManager().beginTransaction().replace(R.id.linearLayout,new ShoppyFragment()).commit();bot.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {@Overridepublic boolean onNavigationItemSelected(@NonNull MenuItem item) {Fragment f1=null;switch (item.getItemId()){case R.id.index:f1=new IndexFragment();break;case R.id.shoppy:f1=new ShoppyFragment();break;case R.id.user:f1=new UserFragment();break;}getSupportFragmentManager().beginTransaction().replace(R.id.linearLayout,f1).commit();return true;}});}
}

她的xml代码

<?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"><LinearLayoutandroid:id="@+id/linearLayout"android:layout_width="0dp"android:layout_height="0dp"android:layout_marginStart="1dp"android:layout_marginEnd="1dp"android:layout_marginBottom="14dp"android:orientation="horizontal"app:layout_constraintBottom_toTopOf="@+id/bottomNavigationView"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toTopOf="parent"></LinearLayout><com.google.android.material.bottomnavigation.BottomNavigationViewandroid:id="@+id/bottomNavigationView"android:layout_width="401dp"android:layout_height="69dp"android:layout_marginStart="6dp"android:layout_marginEnd="6dp"android:layout_marginBottom="1dp"app:layout_constraintBottom_toBottomOf="parent"app:layout_constraintEnd_toEndOf="parent"app:layout_constraintStart_toStartOf="parent"app:layout_constraintTop_toBottomOf="@+id/linearLayout"app:menu="@menu/menu"></com.google.android.material.bottomnavigation.BottomNavigationView></androidx.constraintlayout.widget.ConstraintLayout>

菜单界面注意菜单界面必须创建路径叫menu的文件夹

android:icon="@drawable/home" 表示下面的图标

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"><itemandroid:icon="@drawable/home"android:title="主页"android:id="@+id/index"/><itemandroid:icon="@drawable/shoppy"android:title="订单"android:id="@+id/shoppy"/><itemandroid:icon="@drawable/user"android:title="我的"android:id="@+id/user"/></menu>

三个子界面（都是这样子的界面除了中的R.layout.fragment_user需要改成自己的布局）所以复制了一个自己复制就可以或者创建的时候选择

return inflater.inflate(R.layout.fragment_user, container, false);

public class UserFragment extends Fragment {@Overridepublic View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {// Inflate the layout for this fragmentreturn inflater.inflate(R.layout.fragment_user, container, false);}
}

她的xml文件

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"tools:context=".menu.UserFragment"><!-- TODO: Update blank fragment layout --><TextViewandroid:layout_width="match_parent"android:layout_height="match_parent"android:text="@string/hello_blank_fragment" /></FrameLayout>

主要的代码结构