System Resources

import { runningLock } from '@kit.BasicServicesKit';
import { hilog } from '@kit.PerformanceAnalysisKit';
import { BusinessError } from '@kit.BasicServicesKit';

// Return to the background to release the lock
runningLock.create('running_lock_test', runningLock.RunningLockType.BACKGROUND)
  .then((lock: runningLock.RunningLock) => {
    try {
      lock.unhold();
    } catch (error) {
      let err = error as BusinessError;
      hilog.warn(0x000, 'testTag', `setColorMode failed, code=${err.code}, message=${err.message}`);
    }
  })
  .catch((err: Error) => {
    console.error('create running lock failed, err: ' + err);
  });

import { UIAbility } from '@kit.AbilityKit';
import { audio } from '@kit.AudioKit';
import { BusinessError } from '@kit.BasicServicesKit';
// ...
export default class EntryAbility extends UIAbility {
  // ...

  onForeground(): void {
    //Apply for the resources required by the system, or reapply for the resources released in onBackground ()
    audio.createAudioRenderer(audioRendererOptions,(err: BusinessError) => {});
  }

  onBackground(): void {
    //Release resources when the UI is invisible
    audioRenderer.stop((err: BusinessError) => {});
  }
}