【每日学点鸿蒙知识】动画主动停止、右滑左滑收拾、登录页跳转、Web组件拉起相册、怎么禁止侧滑

1、HarmonyOS 无限循环的 animateTo 动画有办法主动停止吗？

@Component
export struct Test {
  @State message: string = 'Hello World';
  @State opacityValue: number = 1

  build() {
    Row() {
      Column() {
        Text(this.message)
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .opacity(this.opacityValue)
        Button("开始动画").onClick(() => {
          animateTo({ duration: 1000, iterations: -1, playMode: PlayMode.AlternateReverse }, () => {
            this.opacityValue = 0
          })
        })
        Button("结束动画").onClick(() => {
          animateTo({
            duration: 0, iterations: 1, onFinish: () => {
              this.opacityValue = 1
            }
          }, () => {
            this.opacityValue = 0.9
          })
        })
      }
      .width('100%')
    }
    .height('100%')
  }
}

2、HarmonyOS 系统右滑和左滑手势如何关闭或者如何更改手势交互？

在项目部分页面需要关闭系统右滑和左滑手势，部分页面需要修改右滑和左滑手势事件。

通过onBackPress事件拦截，返回true表示页面自己处理返回逻辑，参考链接：https://developer.huawei.com/consumer/cn/doc/harmonyos-faqs-V5/faqs-arkui-29-V5

3、HarmonyOS 登录页面跳转？

应用登录之后，进入应用首页，接着进入下一级页面，在某个下一级页面需要弹出登录页面，登录完成之后，需要显示的是应用首页，这个要怎么管控页面的跳转，才能回到应用首页

问题中提到的场景，在登录页面登录完成之后都需要回到应用首页；直接清空路由栈，然后push到首页这种是否可以满足业务场景

Button("登录")
  .onClick((event: ClickEvent) => {
    //业务处理，登录校验
    //然后清空路由栈，跳转到首页
    router.clear()
    router.pushUrl({
      url:'pages/Index'
    })
  })

4、HarmonyOS Web组件如何拉起相册，相机以及文件管理器？

import web_webview from '@ohos.web.webview'
import { common } from '@kit.AbilityKit'
import { uri, util } from '@kit.ArkTS'
import fs from '@ohos.file.fs';
import picker from '@ohos.file.picker'
import { BusinessError } from '@kit.BasicServicesKit';

class testClass {
  base64Str: string

  constructor(base64Str:string) {
    this.base64Str=base64Str;
  }

  test(): string {
    return "2123";
  }

  toString(): void {
    console.log('Web Component toString');
  }
}

@Entry
@Component
struct WebComponent {
  controller: web_webview.WebviewController = new web_webview.WebviewController()
  //定义一个全局的string类型的数组，用来存放通过picker拉起后选择完图片后图片的uri
  @State uris: Array<string> = []
  @State base64Str : string = ""
  @State testObj: testClass = new testClass(this.base64Str);
  aboutToAppear() {
    web_webview.WebviewController.setWebDebuggingAccess(true);
  }
  build() {
    Column() {

      Web({ src: $rawfile('TestonShowFileSelector.html'), controller: this.controller })
        .javaScriptAccess(true)
        .domStorageAccess(true)
        .onShowFileSelector((event) => {
          // //-------调用相册-------------------------
          console.log('MyFileUploader onShowFileSelector invoked')
          const photoSelectOptions = new picker.PhotoSelectOptions();
          // 过滤选择媒体文件类型为IMAGE_VIDEO_TYPE
          photoSelectOptions.MIMEType = picker.PhotoViewMIMETypes.IMAGE_VIDEO_TYPE;
          // 选择媒体文件的最大数目
          photoSelectOptions.maxSelectNumber = 8;
          //let uris: Array<string> = [];
          const photoViewPicker = new picker.PhotoViewPicker();
          photoViewPicker.select(photoSelectOptions).then((photoSelectResult: picker.PhotoSelectResult) => {
            this.uris = photoSelectResult.photoUris;
            let file1 = fs.openSync(this.uris[0])
            let array:ArrayBuffer = new ArrayBuffer(fs.statSync(file1.fd).size)
            fs.readSync(file1.fd,array)
            let unit = new Uint8Array(array)
            let base64 = new util.Base64Helper();
            let mystr = base64.encodeToStringSync(unit);
            this.base64Str = "myFunction(\"" + mystr + "\")"
            this.controller.runJavaScript(this.base64Str)
            console.info('photoViewPicker.select to file succeed and uris are:' + this.uris);//file://media/Photo/11/IMG_1713942933_005/IMG_20240424_151353.jpg
          }).catch((err: BusinessError) => {
            console.error(`Invoke photoViewPicker.select failed, code is ${err.code}, message is ${err.message}`);
          })

          return false
          //----调用文件管理器-----------------
          // console.log('MyFileUploader onShowFileSelector invoked')
          // const documentSelectOptions = new picker.DocumentSelectOptions();
          // // 选择媒体文件的最大数目
          // documentSelectOptions.maxSelectNumber = 2;
          // const documentViewPicker = new picker.DocumentViewPicker();
          // documentViewPicker.select(documentSelectOptions).then((DocumentSelectResult: Array<string>) => {
          //   this.uris = DocumentSelectResult;
          //   console.info('photoViewPicker.select to file succeed and uris are:' + this.uris);
          // }).catch((err: BusinessError) => {
          //   console.error(`Invoke photoViewPicker.select failed, code is ${err.code}, message is ${err.message}`);
          // })
          // return false

          -----相机--------------------------------
          // const context = getContext(this) as common.UIAbilityContext
          // context.startAbilityForResult({
          //   action:"ohos.want.action.imageCapture",
          //   parameters:{
          //     callBundleName:"com.hm.imageshow"
          //   }
          // }).then((res)=>{
          //   console.log("testTag - " +JSON.stringify(res));
          //   let str:string = res.want?.parameters!["resourceUri"] as string
          //   console.log("str"+str);//file://media/Photo/11/IMG_1713942933_005/IMG_20240424_151353.jpg
          //   let fd = fs.openSync(str).fd
          //   this.uris[0] = str
          //   let arr:ArrayBuffer = new ArrayBuffer(128)
          //   fs.readSync(fd,arr)
          //   console.log("testTag - " + str);
          //
          // })
          //return false


        })

    }
  }
}
<form id="upload-form" enctype="multipart/form-data">
    <!-- 修改type属性为camera -->
    <input type="file" id="upload" name="upload" accept="image/*" capture="camera" />
    <!-- 添加一个图片元素用于展示图片 -->
    <img id="preview"/>
</form>
<div id="155134"></div>

5、HarmonyOS 怎么禁止侧滑？

可以在页面生命周期中返回true onBackPress() { return true }