• 上图
  

• 引入

implementation 'com.google.android.material:material:1.4.0'

• 属性

• 使用

1. 布局源代码

2. menu源代码

3. activity 源代码

package com.yyf.demo;import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.Window;import com.yyf.demo.databinding.ActivityMain3Binding;public class MainActivity extends AppCompatActivity {private ActivityMain3Binding binding;private static final String TAG = "MainActivity";@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);supportRequestWindowFeature(Window.FEATURE_NO_TITLE);binding = ActivityMain3Binding.inflate(getLayoutInflater());setContentView(binding.getRoot());//引入toolBarsetSupportActionBar(binding.toolbar);//toolBar 左侧返回图标事件binding.toolbar.setNavigationOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {Log.d(TAG, "onClick: 点击了返回图标");}});}//引入menu布局文件@Overridepublic boolean onCreateOptionsMenu(Menu menu) {getMenuInflater().inflate(R.menu.menu, menu);return true;}//menu选项被点击响应事件@Overridepublic boolean onOptionsItemSelected(@NonNull MenuItem item) {switch (item.getItemId()) {case R.id.scan:Log.d(TAG, "onOptionsItemSelected: " + item.getTitle());break;}return super.onOptionsItemSelected(item);}
}

• 注意事项

java.lang.IllegalStateException: This Activity already has an action bar supplied by the window decor. Do not request Window.FEATURE_SUPPORT_ACTION_BAR and set windowActionBar to false in your theme to use a Toolbar instead.
该异常说明已经有一个标题栏存在,不能再去设置一个,解决方式如下:

1. 在activity中setContentView()前设置supportRequestWindowFeature(Window.FEATURE_NO_TITLE);
2. 在AndroidManifest.xml中修改application标签的theme属性

• 文中Activity使用了ViewBinding 若直接复制报错,请在项目中build.gradle android标签 下开启

	buildFeatures{viewBinding=true}