Ionic v4.12 ion-picker 找不到任何方法来处理某列的项目选择更改

Question

I user ion-picker component with ionic V4.12, and I have 3 columns. When I select one item of the first column, I need to filter items of the second column, but I cannot find any way to resolve my problem

I found PickerColumn has refresh function ,but still not work

import { PickerController } from '@ionic/angular';

@Component({
  ...
})
export class ComponentPage {
  constructor(public pickerCtrl: PickerController) { }

  async openPicker() {
    const picker = await this.pickerCtrl.create({
      buttons: [{
        text: 'Done',
      }],
      columns: [
        {
          name: 'days',
          options: [
            {
              text: '1',
              value: 1
            },
            {
              text: '2',
              value: 2
            },
            {
              text: '3',
              value: 3
            },
          ]
        },
        {
          name: 'years',
          options: [
            {
              text: '1992',
              value: 1992
            },
            {
              text: '1993',
              value: 1993
            },
            {
              text: '1994',
              value: 1994
            },
          ]
        },
      ]
    });
    await picker.present();
  }
}

When I select 1 on days column, I just want to show the item named 1994.

Answer 1

I put a request to IONIC TEAM,and the answer is listen ionPickerColChange Even

picker.addEventListener('ionPickerColChange', async (event: any) => {
     here handle some logic
} 

Answer 2

You can listen to the onDidDismiss method like so:

async openPicker() {
    const picker = await this.pickerCtrl.create({
      buttons: [{
        text: 'Done',
      }],
      columns: [
        {
          name: 'days',
          options: [
            {
              text: '1',
              value: 1
            },
            {
              text: '2',
              value: 2
            },
            {
              text: '3',
              value: 3
            },
          ]
        },
        {
          name: 'years',
          options: [
            {
              text: '1992',
              value: 1992
            },
            {
              text: '1993',
              value: 1993
            },
            {
              text: '1994',
              value: 1994
            },
          ]
        },
      ]
    });

    picker.onDidDismiss().then(({data}) => console.log(data.years.value));

    await picker.present();
  }