Android底部导航栏BottomNavigationView+Fragment

主要代码

1：添加依赖

implementation 'com.google.android.material:material:1.2.1'

2：布局文件activity_main.xml

<?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"
    tools:context=".MainActivity">
    <FrameLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:id="@+id/fragment"
        />
    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottomNavigagionview"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:background="#FFFFFF"
        app:menu="@menu/navigation"
        />
</RelativeLayout>

3：菜单menu/navigation

<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android">
    <item
        android:id="@+id/navigation1"
        android:title="@string/app_fragmner1"
        app:showAsAction="ifRoom"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_home"
        />
    <item
        android:id="@+id/navigation2"
        android:title="@string/app_fragmner2"
        app:showAsAction="ifRoom"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_my_location"
        />
    <item
        android:id="@+id/navigation3"
        android:title="@string/app_fragmner3"
        app:showAsAction="ifRoom"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_home"
        />
    <item
        android:id="@+id/navigation4"
        android:title="@string/app_fragmner4"
        app:showAsAction="ifRoom"
        android:enabled="true"
        android:icon="@drawable/ic_baseline_my_location"
        />
</menu>

4:颜色选择器：bottom_navigation_item_selector.xml

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

5：activity中的Java代码

package com.example.androoid;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.fragment.app.Fragment;


import android.os.Bundle;
import android.view.MenuItem;


import com.google.android.material.bottomnavigation.BottomNavigationView;

import java.util.ArrayList;

public class MainActivity extends AppCompatActivity {
    private BottomNavigationView bottomNavigationView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        if (savedInstanceState == null){
            getSupportFragmentManager().beginTransaction().replace(R.id.fragment,new homeFragment()).commit();
        }
        initviewpager();
    }

    private void initviewpager() {
        bottomNavigationView=findViewById(R.id.bottomNavigagionview);

        bottomNavigationView.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
            @Override
            public boolean onNavigationItemSelected(@NonNull MenuItem item) {
                Fragment fragment=null;
                switch (item.getItemId()){
                    case R.id.navigation1:
                        fragment=new homeFragment();
                        break;
                    case R.id.navigation2:
                        fragment=new homeFragment2();
                        break;
                    case R.id.navigation3:
                        fragment=new homeFragment();
                        break;
                    case R.id.navigation4:
                        fragment=new homeFragment2();
                        break;
                }
                getSupportFragmentManager().beginTransaction().replace(R.id.fragment,fragment).commit();
                return true;
            }
        });

    }
}

6:Fragment的xml

<?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=".homeFragment">

<!-- TODO: Update blank fragment layout -->
<TextView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:gravity="center"
    android:textSize="36sp"
    android:id="@+id/text"
    android:background="#Ff0000"
    android:text="@string/hello_blank_fragment" />

</FrameLayout>

7:Fragment的Java代码:

package com.example.androoid;

import android.os.Bundle;

import androidx.fragment.app.Fragment;

import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import org.w3c.dom.Text;


public class homeFragment extends Fragment {
    View view;




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

}

Ok简单的一个Android底部导航切换就完成了