Automatic Focus Acquisition, Global Popups, Data Change Monitoring, Size Display Anomalies

[Daily HarmonyOS Next Knowledge] Automatic Focus Acquisition, Global Popups, Data Change Monitoring, Size Display Anomalies, One-Click Closure of All Pages

1. HarmonyOS TextInput automatic focus issue?

A TextInput and a button are arranged vertically on the page. Clicking the button triggers a popup using CustomDialogController. After closing the popup, the TextInput automatically gains focus. How to prevent automatic focus acquisition? Setting .defaultFocus(false).groupDefaultFocus(false) is ineffective.

Use requestFocus as shown in the demo:

import prompt from '@ohos.prompt';

@Entry
@Component
struct Index {
  @State message: string = 'Hello World';
  @State isboole: boolean = true;

  build() {
    Row() {
      Column() {
        Text(this.message)
          .id('1sa')
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
        Button('I will get focus')
          .key('BBB')
        TextInput({ placeholder: 'AAAAA' })
          .id('AAAA1')
          .type(InputType.Normal)
        Button('Click to transfer focus')
          .onClick(() => {
            let res = focusControl.requestFocus('BBB')
            if (res) {
              prompt.showToast({ message: 'Request success' })
            } else {
              prompt.showToast({ message: 'Request failed' })
            }
          })
        Button('Click to get focus')
          .onClick(() => {
            this.isboole = true
            sendEventByKey("AAAA1", 10, "") // Send click event to component with id "longClick"
          })
      }
      .width('100%')
    }
    .height('100%')
  }
}

2. How to encapsulate global popups in HarmonyOS? What is the best practice?

1. What is the optimal way to encapsulate public popups?
2. How to use popups in non-UI components?

To encapsulate a globally usable popup, use promptAction to wrap a custom dialog:

Reference documentation: See the example code for promptAction.openCustomDialog (https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-promptaction-V5#promptactionopencustomdialog11)

Sample code:

let customDialogId: number = 0

export function showCustomDialog() {
  let result: CustomDialogController = new CustomDialogController({
    builder: SimpleDialog({}),
    alignment: DialogAlignment.Bottom,
    customStyle: true,
    offset: {
      dx: 0,
      dy: CommonConstants.DY_OFFSET
    }
  })
  result.open()
}

...

onClick: () => {
  promptAction.openCustomDialog({
    builder: showCustomDialog.bind(this)
  }).then((dialogId: number) => {
    customDialogId = dialogId;
  })
}

// Confirm/cancel popup
promptAction.closeCustomDialog(customDialogId)

3. How to monitor data changes of isNormalMode within a @builder decorator in HarmonyOS?

Need to update the Image component's source when isNormalMode changes. Currently, if written directly in build without @builder, the Image updates normally. When written in @builder, data changes are not detected. How to monitor data changes within @builder?

@State isNormalMode: boolean = true;

@Builder
showImage(source: string | Resource, onImageClick: () => void = () => {}) {

  Image(source)
    .fitOriginalSize(true)
    .objectFit(ImageFit.Auto)
    .width(Constants.FULL_PARENT)
    .onClick(() => {
      console.log("obclick")
      onImageClick();
    })
    .padding({ /// Inner area padding
      top: $r('app.float.screen_margin_left_right')
    })
}

build() {
  Stack({ alignContent: Alignment.TopStart }) {
    Flex({ direction: FlexDirection.Column }) {

      TitleBar({ model: $model })

      Column() {

        this.showImage(this.isNormalMode ? $r('app.media.normal_mode_selected') : $r('app.media.normal_mode_unselect'), () => {
          console.log("setImageobclick")
          this.isNormalMode = true;
        });

        this.showImage(this.isNormalMode ? $r('app.media.easy_mode_unselect') : $r('app.media.easy_mode_selected'), () => {
          console.log("setImageobclick")
          this.isNormalMode = false;
        });
      }
      .padding({ /// Inner area padding
        left: $r('app.float.screen_margin_left_right'),
        right: $r('app.float.screen_margin_left_right'),
      })
      .width(Constants.FULL_PARENT)
      .height(Constants.FULL_PARENT)
    }
  }
  .width(Constants.FULL_PARENT)
  .height(Constants.FULL_PARENT)
}

When calling a @Builder-decorated function, parameters are passed by value. Changes to state variables (passed by value) do not trigger UI refresh within @builder. For state variables, use reference passing.

Reference: https://developer.huawei.com/consumer/cn/doc/harmonyos-guides-V5/arkts-builder-V5

Sample code:

class ImageParams {
  imageUrl: string | Resource = ''
  onImageClick: () => void = () => {
  }
}

@Entry
@Component
struct Index {
  @State isNormalMode: boolean = true;
  @State imgUrl: string | Resource = $r('app.media.img1')

  @Builder
  showImageNew(params: ImageParams) {

    Image(params.imageUrl)
      .fitOriginalSize(true)
      .objectFit(ImageFit.Auto)
      .width(200)
      .onClick(() => {
        console.log("obclick")
        params.onImageClick();
      })
  }

  @Builder
  showImage(source: string | Resource, onImageClick: () => void = () => {
  }) {
    Image(source)
      .fitOriginalSize(true)
      .objectFit(ImageFit.Auto)
      .width(200)
      .onClick(() => {
        console.log("obclick")
        onImageClick();
      })
  }

  build() {
    Stack({ alignContent: Alignment.TopStart }) {
      Flex({ direction: FlexDirection.Column }) {

        Column() {

          Text("Status: " + this.isNormalMode)
          Text(" imgUrl: " + JSON.stringify(this.imgUrl))

          this.showImage(this.imgUrl, () => {
            console.log("setImageobclick")
            this.isNormalMode = !this.isNormalMode;
            this.imgUrl = this.isNormalMode ? $r('app.media.img1') : $r('app.media.img2')
          })

          Button("Change type (only status, image unchanged)").onClick(() => {
            this.isNormalMode = !this.isNormalMode
          })

          //=================Use the following approach==========================
          this.showImageNew(
            {
              imageUrl: this.imgUrl,
              onImageClick: () => {
                this.isNormalMode = !this.isNormalMode;
                this.imgUrl = this.isNormalMode ? $r('app.media.img1') : $r('app.media.img2')
              }
            }
          )
          if (this.isNormalMode) {
            this.showImageNew(
              {
                imageUrl: $r("app.media.img1"),
                onImageClick: () => {
                  this.isNormalMode = !this.isNormalMode;
                  this.imgUrl = this.isNormalMode ? $r('app.media.img1') : $r('app.media.img2')
                }
              }
            )
          } else {
            this.showImageNew(
              {
                imageUrl: $r("app.media.img2"),
                onImageClick: () => {
                  this.isNormalMode = !this.isNormalMode;
                  this.imgUrl = this.isNormalMode ? $r('app.media.img1') : $r('app.media.img2')
                }
              }
            )
          }

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

4. HarmonyOS component size display anomaly?

In the following code, the width is set to 100%, but the actual width does not fill the screen as shown in the screenshot.

@Entry
@Component
struct AlignRuleTestPage {
  @State message: string = 'Hello World';

  build() {
    RelativeContainer() {
      Text(this.message)
        .id('AlignRuleTestPageHelloWorld')
        .fontSize(30)
        .width("100%")
        .aspectRatio(6)
        .margin({
          top: "14%"
        })
        .backgroundColor(Color.Red)
        .fontWeight(FontWeight.Bold)
        .alignRules({
          top: { anchor: '__container__', align: VerticalAlign.Top },
          left: { anchor: '__container__', align: HorizontalAlign.Start },
          right: { anchor: '__container__', align: HorizontalAlign.End },
        })
    }
    .height('100%')
    .width('100%')
  }
}

Refer to the demo:

@Component
struct Index {
  @State message: string = 'Hello World';

  build() {
    RelativeContainer() {
      Text(this.message)
        .id('AlignRuleTestPageHelloWorld')
        .fontSize(30)//.aspectRatio(0)  Remove this line
        .margin({
          top: "14%"
        })
        .backgroundColor(Color.Red)
        .fontWeight(FontWeight.Bold)
        .width("100%")
        .height('100%')
    }
    .height('100%')
    .width('100%')
  }
}

Reference for aspectRatio: https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/ts-universal-attributes-layout-constraints-V5

5. How to close all previous pages with one click in HarmonyOS?

After navigating through multiple pages (e.g., A-B-C-D), how to close A, B, and C with one click?

To close pages A and B, use router.clear() to clear all historical pages from the stack, leaving only the current page as the top.

Reference: https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/js-apis-router-V5