HarmonyOS textpicker组件的使用咨询

// xxx.ets 
class bottom { 
  bottom:number = 50 
} 
let bott:bottom = new bottom() 
@Entry 
@Component 
struct TextPickerExample { 
  private select: number = 1 
  private apfruits: string[] = ['apple1', 'apple2', 'apple3', 'apple4'] 
  private orfruits: string[] = ['orange1', 'orange2', 'orange3', 'orange4'] 
  private pefruits: string[] = ['peach1', 'peach2', 'peach3', 'peach4'] 
  private multi: string[][] = [this.apfruits, this.orfruits, this.pefruits] 
  private cascade: TextCascadePickerRangeContent[] = [ 
    { 
      text: '辽宁省', 
      children: [{ text: '沈阳市', children: [{ text: '沈河区' }, { text: '和平区' }, { text: '浑南区' }] }, 
        { text: '大连市', children: [{ text: '中山区' }, { text: '金州区' }, { text: '长海县' }] }] 
    }, 
    { 
      text: '吉林省', 
      children: [{ text: '长春市', children: [{ text: '南关区' }, { text: '宽城区' }, { text: '朝阳区' }] }, 
        { text: '四平市', children: [{ text: '铁西区' }, { text: '铁东区' }, { text: '梨树县' }] }] 
    }, 
    { 
      text: '黑龙江省', 
      children: [{ text: '哈尔滨市', children: [{ text: '道里区' }, { text: '道外区' }, { text: '南岗区' }] }, 
        { text: '牡丹江市', children: [{ text: '东安区' }, { text: '西安区' }, { text: '爱民区' }] }] 
    } 
  ] 
 
  build() { 
    Column() { 
 
      TextPicker({ range: this.apfruits, selected: this.select }) 
        .onChange((value: string | string[], index: number | number[]) => { 
          console.info('Picker item changed, value: ' + value + ', index: ' + index) 
        }).margin(bott) 
 
      TextPicker({ range: this.multi }) 
        .onChange((value: string | string[], index: number | number[]) => { 
          console.info('TextPicker 多列:onChange ' + JSON.stringify(value) + ', ' + 'index: ' + JSON.stringify(index)) 
        }).margin(bott) 
 
      TextPicker({ range: this.cascade }) 
        .onChange((value: string | string[], index: number | number[]) => { 
          console.info('TextPicker 多列联动:onChange ' + JSON.stringify(value) + ', ' + 'index: ' + JSON.stringify(index)) 
        }) 
    } 
  } 
}