自定义组件onMeasureSize的使用

export class GlobalContext {  
  private constructor() {  
  }  
  private static instance: GlobalContext;  
  private _objects = new Map<string, Object>();  
  public static getContext(): GlobalContext {  
    if (!GlobalContext.instance) {  
      GlobalContext.instance = new GlobalContext();  
    }  
    return GlobalContext.instance;  
  }  
  getObject(value: string): Object | undefined {  
    return this._objects.get(value);  
  }  
  setObject(key: string, objectClass: Object): void {  
    this._objects.set(key, objectClass);  
  }  
}

let windowClass:window.Window = windowStage.getMainWindowSync();      
 GlobalContext.getContext().setObject('windowClass',windowClass)

import { window } from '@kit.ArkUI';  
import { GlobalContext } from './GlobalContext'  
@Entry  
@Component  
struct Index {  
  @State windowWidth: number = 0;  
  aboutToAppear(): void {  
    let windowClass: window.Window = GlobalContext.getContext().getObject('windowClass') as window.Window;  
    let rect: window.Rect = windowClass.getWindowProperties().windowRect;  
    this.windowWidth = px2vp(rect.width);  
  }  
  build() {  
    Column() {  
      CustomLayout({ builder: ColumnChildren, windowWidth: this.windowWidth })  
    }  
  }  
}  
@Builder  
function ColumnChildren() {  
  ForEach([1], (index: number) => {  
    Text('S' + index)  
      .fontSize(30)  
      .height('100%')  
      .borderWidth(2)  
      .offset({ x: 10, y: 20 })  
  })  
}  
@Component  
struct CustomLayout {  
  @Builder  
  doNothingBuilder() {  
  };  
  @BuilderParam builder: () => void = this.doNothingBuilder;  
  @State startSize: number = 100;  
  @Prop windowWidth: number;  
  result: SizeResult = {  
    width: 0,  
    height: 0  
  };  
  onMeasureSize(selfLayoutInfo: GeometryInfo, children: Array<Measurable>, constraint: ConstraintSizeOptions) {  
    let size = this.windowWidth/6;  
    children.forEach((child) => {  
      let result: MeasureResult = child.measure({  
        minHeight: size * 2,  
        minWidth: size,  
        maxWidth: size,  
        maxHeight: size * 2  
      })  
    })  
    this.result.width = size;  
    this.result.height = size * 2;  
    return this.result;  
  }  
  build() {  
    this.builder()  
  }  
}