代码片段：Android创建导航栏菜单

1、在menu文件夹下创建xml菜单文件

<?xml version="1.0" encoding="utf-8"?>
<menu 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">
    <item
        android:id="@+id/export_item"
        android:orderInCategory="100"
        android:title="导出"
        app:showAsAction="always"
        tools:ignore="AlwaysShowAction,HardcodedText"/>

    <item
        android:id="@+id/clear_item"
        android:orderInCategory="100"
        android:title="清理"
        app:showAsAction="always"
        tools:ignore="AlwaysShowAction,HardcodedText"/>
</menu>

如下图

2、在Activity中生成菜单并添加响应事件

@Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.meters_menu,menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if(item.getItemId() == R.id.export_item){
            exportAll();
        }else if(item.getItemId() == R.id.clear_item){
            clearAll();
        }
        return super.onOptionsItemSelected(item);
    }