求大佬告知如何实现防截屏功能

import { BusinessError } from '@ohos.base'; 
let isPrivacyMode: boolean = true; 
try { 
  windowClass.setWindowPrivacyMode(isPrivacyMode, (err: BusinessError) => { 
    const errCode: number = err.code; 
    if (errCode) { 
      console.error('Failed to set the window to privacy mode. Cause:' + JSON.stringify(err)); 
      return; 
    } 
    console.info('Succeeded in setting the window to privacy mode.'); 
  }); 
} catch (exception) { 
  console.error('Failed to set the window to privacy mode. Cause:' + JSON.stringify(exception)); 
}