??? ?? ??? ???? 3?? ?? ??? ???? ????.

1. ? ?? ?? ??? ?? ??? ???? ???? ?????.
2. ? ??? ?? ??? ??? ?? ?? ??? ???? ?? ??(??? ?? ??)? ????? ????.
3. ? ??? ?? ??? ???? ?? ?? ?????.

??? ? ?? ?? ???? ?? ?? ??? ?? ????.

??? ?? 2?? ?? ??? ???? ? ???? ? ?? ??? ? ????.

? ?? ?? ??, Cascade Form Basic
? ?? ????, Cascade ?? ??

??? ?????.

???

• ???
• ?? ?? ??
• ?? ?? ???
• ?? ???
• ??? ??
• ?? ??
• ?? ?
• ?? ??
• ?????(?, ??, ??)
• ??
• ?? ???

?? ??

5?? ???? ??? ?? ?? ?? ??????.

import React, { useState, useEffect } from "react";
import { ScrollView, View, Text, StyleSheet, TouchableOpacity } from "react-native";
import { Dropdown } from "react-native-element-dropdown";
import { Snackbar } from "react-native-paper";

var snackMsg = "";
export default function App() {
  const [refreshPage, setRefreshPage] = useState(false);
  const [visible, setVisible] = useState(false);

  const onToggleSnackBar = () => setVisible(!visible);
  const onDismissSnackBar = () => setVisible(false);

  const resetForm = () => {
  };

  return (
    <ScrollView>



<p>refreshPage state variable is used to refresh the page in all the situations. </p>

<p><img src="/static/imghw/default1.png"  data-src="https://img.php.cn/upload/article/000/000/000/173363402014343.jpg"  class="lazy" alt="Cascading Form React Native Advanced" /></p>

<p>Now, These fields are going to be converted as dynamic. </p>

<h3>
  
  
  Form Field Object
</h3>

<p>Previously we had 3 separate objects for 3 different fields, but here all fields data placed under one form field object.<br>
</p>

<pre class="brush:php;toolbar:false"> . . .
const formFields = {
  country: {
    fieldId: "country",
    label: "Country",
    labelField: "name",
    valueField: "countryId",
    parents: [],
    list: [],
    selectedItem: {},
    selectedValue: null,
    onValueSelected: () => null,
  },
  state: {
    fieldId: "state",label: "State",labelField: "name",valueField: "stateId",
    parents: ["country"],list: [],selectedItem: {},selectedValue: null,
    onValueSelected: () => null,
  },
  city: {
    fieldId: "city",label: "City",labelField: "name",valueField: "cityId",
    parents: ["country", "state"],list: [],selectedItem: {},
    selectedValue: null,onValueSelected: () => null,
  },
  village: {
    fieldId: "village",label: "Village",labelField: "name",
    valueField: "villageId",
    parents: ["country", "state", "city"],
    list: [],selectedItem: {},selectedValue: null,
    onValueSelected: () => null,
  },
  street: {
    fieldId: "street",label: "Street",labelField: "name",
    valueField: "streetId",
    parents: ["country", "state", "city", "village"],
    list: [],selectedItem: {},selectedValue: null,onValueSelected: () => null,
  },
};

 . . .
export default function App() {
   . . .
}

??? ??? ?? ???? ??? ??? ?? ???? ???? ? ?????.

• fieldId ??? ID
• label ?? ?? ??
• labelField? ???? ?? ??? ???? ??? ??? ?????
• valueField? ???? ? ??? ?????
• ?? ??? ?? ??? ??? ??? ?????
• ?? ???? ?? ??
• selectedItem ????? ?? ?? ?? ??
• selectedValue ??? ?
• onValueSelected? ?? ???? ???? ?? ??/??? ? ??/?????. ???? ? ???? ???????.

?? ?? ???

???? ??? ???? ????? ?? ?? ?? ???? ???? ?? ?? ???? ??? ?? ??? ??? ? ????.

export default function App() {
  . . .
    return (
    <View>



<p>handle focus / blur<br>
</p>

<pre class="brush:php;toolbar:false">var focusField = "";
export default function App() {
. . .

 const changeFocusField = (fld = "") => {
  focusField = fld;
  setRefreshPage(!refreshPage);
 };
. . .
}

<ZDropDown
. . .
  isFocus={focusField === ele}
  onFocus={() => {
    changeFocusField(ele);
  }}
  onBlur={() => changeFocusField("")}
  onChange={(item) => {}}
 />

?? ???

??, ?, ?, ??, ?? ??? ?? ?? ??????.

const listCountry = [
  { countryId: "1", name: "india" },
  { countryId: "2", name: "uk" },
  { countryId: "3", name: "canada" },
  { countryId: "4", name: "us" },
];

const listSate = [
  { stateId: "1", countryId: "1", name: "state1_india" },
  { stateId: "4", countryId: "2", name: "state1_uk" },
  { stateId: "7", countryId: "3", name: "state1_canada" },
  { stateId: "10", countryId: "4", name: "state1_us" },
];

const listCity = [
  { cityId: "1", stateId: "1", countryId: "1", name: "city1_state1_country1" },
  { cityId: "5", stateId: "2", countryId: "1", name: "city5_state2_country1" },
  {
    cityId: "21",stateId: "7",countryId: "3",name:"city21_state7_country3",
  },
  {
    cityId: "26",stateId: "9",countryId: "3",name: "city26_state9_country3",
  },
];

const listVillage = [
  { cityId: "1", villageId: "1", name: "village 1  city 1" },
  { cityId: "2", villageId: "5", name: "village 5  city 2" },
  { cityId: "3", villageId: "9", name: "village 9  city 3" },
  { cityId: "4", villageId: "10", name: "village 10  city 4" },
];

const listStreet = [
  { villageId: "1", streetId: "1", name: "village 1 street 1" },
  { villageId: "1", streetId: "109", name: "village 1 street 109" },
  { villageId: "2", streetId: "2", name: "village 2 street 2" },
  { villageId: "2", streetId: "110", name: "village 2 street 110" },
];
 . . .
export default function App() {
  . . .
}
 . . .

??? ??

?? ?? ???? ? ?? ??? ??? ???? ???. onValueSelected ??? ? ???? ????? ?????. ?? ?? ???? ??? ?????. ??? 5?? ???? ???? ?? ?? ??? ???? ???.

export default function App() {
  . . .
  const allValuesSelected = () => {
    console.log("All fields value selected");
  };

  const loadStreet = async () => {};

  const loadVillage = async () => {};

  const loadCity = async () => {};

  const loadState = async () => {};

  const loadCountry = async () => {};

  const loadPageData = () => {
    formFields.country.onValueSelected = loadState;
    formFields.state.onValueSelected = loadCity;
    formFields.city.onValueSelected = loadVillage;
    formFields.village.onValueSelected = loadStreet;
    formFields.street.onValueSelected = allValuesSelected;    
  };

  return (. . .);
}

?? ?? ???? STATE ??? ???? ?? ??? ???? ??? onValueSelected? loadState ???? ?????. ??? ?? ??? ????? ?????.

  useEffect(() => {
    loadPageData();
  }, []);

  return (. . .);

?? ??

?? ????? ?? ??? ???? ?? ??? ?? ? ?????.

  const loadCountry = async () => {
    formFields.country.list = [...listCountry];
    setRefreshPage(!refreshPage);
  };

  const loadPageData = () => {
    formFields.country.onValueSelected = loadState;
    formFields.state.onValueSelected = loadCity;
    formFields.city.onValueSelected = loadVillage;
    formFields.village.onValueSelected = loadStreet;
    formFields.street.onValueSelected = allValuesSelected;

    loadCountry();
  };

?? ?

???? ?? ?? ???? ?? ?? ?? ?? ???? ???? ??? ? ?? ???? ??? ???? ???.

return (
  . . .
  <ZDropDown
    // . . .
    onChange={(item) => {
      fld.selectedItem = item;
      fld.selectedValue = item[fld.valueField];
      focusField = "";
      fld.onValueSelected();
    }}
  />
  . . .
);

onValueSelected? ?????

?? ??

? ?? ????(??)? ???? ??? ??? ?????. ??? ?? ?? ?? ??? ??? ???? ??? ???. ?? ?? ??? ???? ? ???? ?? ?? ? ?? ???? ?????.

import React, { useState, useEffect } from "react";
import { ScrollView, View, Text, StyleSheet, TouchableOpacity } from "react-native";
import { Dropdown } from "react-native-element-dropdown";
import { Snackbar } from "react-native-paper";

var snackMsg = "";
export default function App() {
  const [refreshPage, setRefreshPage] = useState(false);
  const [visible, setVisible] = useState(false);

  const onToggleSnackBar = () => setVisible(!visible);
  const onDismissSnackBar = () => setVisible(false);

  const resetForm = () => {
  };

  return (
    <ScrollView>



<p>refreshPage state variable is used to refresh the page in all the situations. </p>

<p><img src="/static/imghw/default1.png"  data-src="https://img.php.cn/upload/article/000/000/000/173363402014343.jpg"  class="lazy" alt="Cascading Form React Native Advanced" /></p>

<p>Now, These fields are going to be converted as dynamic. </p>

<h3>
  
  
  Form Field Object
</h3>

<p>Previously we had 3 separate objects for 3 different fields, but here all fields data placed under one form field object.<br>
</p>

<pre class="brush:php;toolbar:false"> . . .
const formFields = {
  country: {
    fieldId: "country",
    label: "Country",
    labelField: "name",
    valueField: "countryId",
    parents: [],
    list: [],
    selectedItem: {},
    selectedValue: null,
    onValueSelected: () => null,
  },
  state: {
    fieldId: "state",label: "State",labelField: "name",valueField: "stateId",
    parents: ["country"],list: [],selectedItem: {},selectedValue: null,
    onValueSelected: () => null,
  },
  city: {
    fieldId: "city",label: "City",labelField: "name",valueField: "cityId",
    parents: ["country", "state"],list: [],selectedItem: {},
    selectedValue: null,onValueSelected: () => null,
  },
  village: {
    fieldId: "village",label: "Village",labelField: "name",
    valueField: "villageId",
    parents: ["country", "state", "city"],
    list: [],selectedItem: {},selectedValue: null,
    onValueSelected: () => null,
  },
  street: {
    fieldId: "street",label: "Street",labelField: "name",
    valueField: "streetId",
    parents: ["country", "state", "city", "village"],
    list: [],selectedItem: {},selectedValue: null,onValueSelected: () => null,
  },
};

 . . .
export default function App() {
   . . .
}

? ??? ?? ?? ???? ?? ? ??? ??? ???? ??? ? ????.

export default function App() {
  . . .
    return (
    <View>



<p>handle focus / blur<br>
</p>

<pre class="brush:php;toolbar:false">var focusField = "";
export default function App() {
. . .

 const changeFocusField = (fld = "") => {
  focusField = fld;
  setRefreshPage(!refreshPage);
 };
. . .
}

?? ?? ???? ??? ???? ???????.

???(??, ??, ??)? ?????.

??? ??? ?? ???? ???? ?? ????.

<ZDropDown
. . .
  isFocus={focusField === ele}
  onFocus={() => {
    changeFocusField(ele);
  }}
  onBlur={() => changeFocusField("")}
  onChange={(item) => {}}
 />

????. ?? ????? ?? ???? ??? ????.

??

???? ??? ???? ?? ?? ??? ???? ???? ???. ??? ?? ?? ???? ?? ??? ???????. ?? ?? ??? ???? ?? ???? ??? ?? ??? ?????.

const listCountry = [
  { countryId: "1", name: "india" },
  { countryId: "2", name: "uk" },
  { countryId: "3", name: "canada" },
  { countryId: "4", name: "us" },
];

const listSate = [
  { stateId: "1", countryId: "1", name: "state1_india" },
  { stateId: "4", countryId: "2", name: "state1_uk" },
  { stateId: "7", countryId: "3", name: "state1_canada" },
  { stateId: "10", countryId: "4", name: "state1_us" },
];

const listCity = [
  { cityId: "1", stateId: "1", countryId: "1", name: "city1_state1_country1" },
  { cityId: "5", stateId: "2", countryId: "1", name: "city5_state2_country1" },
  {
    cityId: "21",stateId: "7",countryId: "3",name:"city21_state7_country3",
  },
  {
    cityId: "26",stateId: "9",countryId: "3",name: "city26_state9_country3",
  },
];

const listVillage = [
  { cityId: "1", villageId: "1", name: "village 1  city 1" },
  { cityId: "2", villageId: "5", name: "village 5  city 2" },
  { cityId: "3", villageId: "9", name: "village 9  city 3" },
  { cityId: "4", villageId: "10", name: "village 10  city 4" },
];

const listStreet = [
  { villageId: "1", streetId: "1", name: "village 1 street 1" },
  { villageId: "1", streetId: "109", name: "village 1 street 109" },
  { villageId: "2", streetId: "2", name: "village 2 street 2" },
  { villageId: "2", streetId: "110", name: "village 2 street 110" },
];
 . . .
export default function App() {
  . . .
}
 . . .

?? ???

????? ?? ??? ???? ? ?? ??? ?????.

export default function App() {
  . . .
  const allValuesSelected = () => {
    console.log("All fields value selected");
  };

  const loadStreet = async () => {};

  const loadVillage = async () => {};

  const loadCity = async () => {};

  const loadState = async () => {};

  const loadCountry = async () => {};

  const loadPageData = () => {
    formFields.country.onValueSelected = loadState;
    formFields.state.onValueSelected = loadCity;
    formFields.city.onValueSelected = loadVillage;
    formFields.village.onValueSelected = loadStreet;
    formFields.street.onValueSelected = allValuesSelected;    
  };

  return (. . .);
}

?? ???????. ?? ?? ?? ??? ????, ??? ?????, ???? ???? ???? ???? ??? ???????.

??? ??? ?? ??? ???? ?? 3?? ?? ?????.

? ???/???? ??? ???? ??? ??? ??? ????. ?????.

?? ??? ???

? ??? ??? ?? React Native Advanced? ?? ?????. ??? ??? PHP ??? ????? ?? ?? ??? ?????!