This content originally appeared on DEV Community and was authored by flfljh
Implementing Responsive Knowledge Point Layouts in HarmonyOS Next
1. Window Breakpoint Detection on App Launch
```typescript
// Update breakpoint based on current window dimensions
private updateBreakpoint(windowWidth: number): void {
try {
// Convert px to vp (virtual pixels)
const windowWidthVp = windowWidth / display.getDefaultDisplaySync().densityPixels;
console.log('Calculated windowWidthVp', windowWidthVp);
let newBp: string = '';
// Determine breakpoint based on width
if (windowWidthVp < 600) {
newBp = 'sm'; // Small screens (phones)
} else if (windowWidthVp < 840) {
newBp = 'md'; // Medium screens (tablets)
} else {
newBp = 'lg'; // Large screens (desktops)
}
// Update global breakpoint state if changed
if (this.curBp !== newBp) {
this.curBp = newBp;
AppStorage.setOrCreate('currentBreakpoint', this.curBp);
}
} catch (err) {
console.error("Display sync failed: " + err.code);
}
}
```
2. Universal Breakpoint Utility Class
```typescript
interface BreakPointTypeOption<T> {
sm?: T; // Small screen configuration
md?: T; // Medium screen configuration
lg?: T; // Large screen configuration
}
/**
* Media Query Utility
* Core of responsive design implementation
*/
export class BreakPointType<T> {
options: BreakPointTypeOption<T>;
constructor(option: BreakPointTypeOption<T>) {
this.options = option;
}
// Get value for current breakpoint
getValue(currentBreakPoint: string): T {
return this.options[currentBreakPoint] as T;
}
}
```
3. Responsive Knowledge Point Layout
```typescript
GridRow({
gutter: Utils.getVp(23) // Responsive gutter spacing
}) {
ForEach(this.knowledgeDataList, (item: KnowledgeItem, tempIndex) => {
GridCol({
// Responsive column span configuration:
// - sm (phones): 12 columns = 1 item per row
// - md (tablets): 6 columns = 2 items per row
// - lg (desktops): 4 columns = 3 items per row
span: { sm: 12, md: 6, lg: 4 }
}) {
KnowledgeListItemLayout({
knowledgeInfo: item,
level: 0
});
}
})
}
```
Implementation Details
1. Breakpoint Detection
- Unit Conversion: Converts physical pixels (px) to virtual pixels (vp) for consistent sizing
-
Breakpoint Thresholds:
-
sm
: < 600vp (mobile phones) -
md
: 600-840vp (tablets) -
lg
: ≥ 840vp (desktops/large tablets)
-
-
Global State: Stores current breakpoint in
AppStorage
for app-wide access
2. Breakpoint Utility Features
- Type-Safe Configuration: Generic class works with any data type
-
Simple Value Retrieval:
getValue()
returns configuration for current breakpoint - Extensible Design: Easily add new breakpoints as needed
3. Responsive Grid Implementation
- GridRow: Container for responsive grid system
- GridCol: Responsive columns with breakpoint-specific spans
-
Layout Behavior:
- Phones (sm): 1 item per row (12/12 columns)
- Tablets (md): 2 items per row (6/12 columns each)
- Large Screens (lg): 3 items per row (4/12 columns each)
-
Gutter Spacing: Responsive spacing between items using
Utils.getVp()
Usage Example
```typescript
// Create responsive configuration
const responsiveColors = new BreakPointType<string>({
sm: '#FF5733', // Red for mobile
md: '#33FF57', // Green for tablets
lg: '#3357FF' // Blue for desktops
});
// Get current color based on breakpoint
const currentColor = responsiveColors.getValue(AppStorage.get('currentBreakpoint'));
```
This implementation provides a complete responsive design solution for HarmonyOS Next applications, enabling adaptive layouts that automatically adjust to different screen sizes and device types.
This content originally appeared on DEV Community and was authored by flfljh

flfljh | Sciencx (2025-06-27T01:23:53+00:00) Implementing Responsive Knowledge Point Layouts in HarmonyOS Next. Retrieved from https://www.scien.cx/2025/06/27/implementing-responsive-knowledge-point-layouts-in-harmonyos-next/
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