HarmonyOS 应用内防截屏功能

首先需要在module.json5中申请隐私窗口权限。然后在onPageShow()中获取当前窗口对象并设置隐私模式。在退出页面的时候，在onPageHide()生命周期中取消隐私模式即可。

参考文档：https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-window-V5

示例参考如下：

//module.json5文件中
{
  "name" : 'ohos.permission.PRIVACY_WINDOW'
}

//EAbility文件中
onWindowStageCreate(windowStage: window.WindowStage) : void{
  let windowClass: window.Window = windowStage.getMainWindowSync();
  // 获取应用主窗口
  AppStorage.setOrCreate("windowClass",windowClass);
}

//Index文件中
import { window } from '@kit.ArkUI';
import { BusinessError } from '@ohos.base';

@Entry
@Component
struct Index43 {
  private windowStage = AppStorage.get("windowStage") as window.WindowStage
  private windowClass = AppStorage.get("windowClass") as window.Window
  @State message: string = 'Hello World';

  build() {
    Row() {
      Column() {
        Text('禁止截屏')
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(() => {

            let isPrivacyMode: boolean = true;
            try {
              this.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));
            }
          })

        Text('允许截屏')
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(() => {

            let isPrivacyMode: boolean = false;
            try {
              this.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));
            }
          })

      }
      .width('100%')
    }
    .height('100%')
  }
}