安卓开发，底部导航栏

1、创建导航栏图标

使用系统自带的矢量图库文件，鼠标右键点击res->New->Vector Asset

修改 Name , Clip art 和 Color

 再创建一个

同样的方法再创建四个按钮

2、添加百分比布局依赖

app\build.gradle.kts 中添加百分比布局依赖，并点击Sync Now

implementation("androidx.percentlayout:percentlayout:1.0.0")

3、创建三个Layout Resource File

1)home.xml

2)learn.xml

3)me.xml

4、创建三个Java Class

1)Home.java

package com.example.bottomnavigationbar;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;
import androidx.appcompat.app.AppCompatActivity;
public class Home extends AppCompatActivity {
    private ImageButton learn,me;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home);
        learn = findViewById(R.id.learn);
        me = findViewById(R.id.me);
        learn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intentToLearn = new Intent(Home.this,Learn.class);
                startActivity(intentToLearn);
                overridePendingTransition(0, 0); // 取消转场动画
            }
        });
        me.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intentToMe = new Intent(Home.this,Me.class);
                startActivity(intentToMe);
                overridePendingTransition(0, 0); // 取消转场动画
            }
        });
    }
}

2)Learn.java

package com.example.bottomnavigationbar;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
public class Learn extends AppCompatActivity {
    private ImageButton home,me;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.learn);
        home = findViewById(R.id.home);
        me = findViewById(R.id.me);
        home.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intentToLearn = new Intent(Learn.this,Home.class);
                startActivity(intentToLearn);
                overridePendingTransition(0, 0); // 取消转场动画
            }
        });
        me.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intentToMe = new Intent(Learn.this,Me.class);
                startActivity(intentToMe);
                overridePendingTransition(0, 0); // 取消转场动画
            }
        });
    }
}

3)Me.java

package com.example.bottomnavigationbar;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageButton;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
public class Me extends AppCompatActivity {
    private ImageButton home,learn;
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.me);
        home = findViewById(R.id.home);
        learn = findViewById(R.id.learn);
        learn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intentToLearn = new Intent(Me.this,Learn.class);
                startActivity(intentToLearn);
                overridePendingTransition(0, 0); // 取消转场动画
            }
        });
        home.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intentToMe = new Intent(Me.this,Home.class);
                startActivity(intentToMe);
                overridePendingTransition(0, 0); // 取消转场动画
            }
        });
    }
}

5、AndroidManifest.xml