在元服务中，监听当前内存达到不同级别

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)}`);
 } 
}