low memory发生时如何监听

import UIAbility from '@ohos.app.ability.UIAbility'; 
import AbilityConstant from '@ohos.app.ability.AbilityConstant'; 
 
class MyUIAbility extends UIAbility { 
  onMemoryLevel(level: AbilityConstant.MemoryLevel) { 
    console.log(`onMemoryLevel, level: ${JSON.stringify(level)}`); 
  } 
}