Image Cropping, Disabling Back Gestures, App Icon Size Specifications, Database Errors

[Daily HarmonyOS Next Knowledge] Image Cropping, Disabling Back Gestures, App Icon Size Specifications, Database Errors, Text Component Omission Display for Excess Length

1. What are the units for the interface area settings (x, y, size) of HarmonyOS image cropping?

The size is specified in pixels (px), and the units for x and y are also pixels (px).

2. How to disable the swipe-back gesture in HarmonyOS?

An overlay layer is added using context.getOverlayManager().addComponentContent, but this layer cannot disable the swipe-back gesture.

Reference code (index page):

import { AppRouter } from './AppRouter' 

import { AppDialog } from './AppDialog' 

import { PrivacyDialogViewBuilder } from './PrivacyDialogView'; 

import { DefaultDialog } from './DefaultDialog';

@Entry

@Component

struct Index {

  @Builder

  PageMap(name: string) {

    DefaultDialog()

  }



  build() {

    Navigation(AppRouter.getInstance().getPathStack()) {

      Stack({ alignContent: Alignment.Center }) {

        Column() {

          Button('Custom Popup Based on Navigation', { stateEffect: true, type: ButtonType.Capsule })

            .onClick(() => {

              AppDialog.build(wrapBuilder(PrivacyDialogViewBuilder))

                .onBackPressed((): boolean => true)

                .open();

            })

        }

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

    }.hideTitleBar(true).navDestination(this.PageMap)

  }

}

3. What are the specifications for HarmonyOS app icon sizes, and what sizes are required for different devices? How does an app adapt to multiple device requirements?

Reference document: https://developer.huawei.com/consumer/cn/doc/design-guides/ux-guidelines-general-0000001760708152#section1353515481417

Visual Style

Color Contrast

Font Size

4. Why does inserting data into a HarmonyOS relationalStore database table that hasn't been created throw an error 14800021?

Errors occur during SQL execution, such as:

1. Inserting or updating a non-created table.
   


2. Inserting or updating a non-existent column.
   


3. Calling undefined functions, etc.
   

5. When a HarmonyOS Text component is set to omit the tail for excess length, it shows abnormal omission in specific cases (omitting early when space remains at the tail).

For omission in mixed text, set the wordBreak property to WordBreak.BREAK_ALL to resolve early omission.


Reference document: https://developer.huawei.com/consumer/cn/doc/harmonyos-references-V5/ts-basic-components-text-V5#textalign

textAlign(value: TextAlign)

Sets the horizontal alignment of the text paragraph.

The text paragraph width fills the Text component width.

The vertical position of the text paragraph can be controlled via the align property. In this component, the align property cannot control the horizontal position (e.g., Alignment.TopStart, Alignment.Top, and Alignment.TopEnd all position content at the top; Alignment.Start, Alignment.Center, and Alignment.End center content vertically; Alignment.BottomStart, Alignment.Bottom, and Alignment.BottomEnd position content at the bottom). The horizontal position is controlled in conjunction with the textAlign property.

When textAlign is set to TextAlign.JUSTIFY, the wordBreak property must be set based on the text content, and the last line of text does not participate in full justification, displaying a horizontal start alignment effect.