如何监听系统公共事件，如熄屏、亮屏、开机等

import CommonEventManager from '@ohos.commonEventManager'; 
let subscriber:CommonEventManager.CommonEventSubscriber; 
let subscribeInfo: CommonEventManager.CommonEventSubscribeInfo = { 
  events: ['usual.event.SCREEN_OFF'], // 订阅灭屏公共事件 
  priority:80 
} 
CommonEventManager.createSubscriber(subscribeInfo, (err, data) => { 
  if (err) { 
    console.error(`Failed to create subscriber. Code is ${err.code}, message is ${err.message}`); 
    return; 
  } 
  console.info('Succeeded in creating subscriber1.'); 
  subscriber = data; 
  // 订阅公共事件回调 
  CommonEventManager.subscribe(subscriber, (err, data) => { 
    if (err) { 
      console.error(`Failed to subscribe common event. Code is ${err.code}, message is ${err.message}`); 
      return; 
    } else { 
      console.info(`Succeeded in subscribe common event Succeeded1 `); 
    } 
  }) 
})