Layout with Flexbox

Flex

flex.tsx

import React from "react";
import { StyleSheet, Text, View } from "react-native";
const Flex = () => {
  return (
    <View style={[styles.container, {
      // Try setting `flexDirection` to `"row"`.
      flexDirection: "column"
    }]}>
      <View style={{ flex: 1, backgroundColor: "red" }} />
      <View style={{ flex: 2, backgroundColor: "darkorange" }} />
      <View style={{ flex: 3, backgroundColor: "green" }} />
    </View>
  );
};
const styles = StyleSheet.create({
  container: {
    flex: 1,
    padding: 20,
  },
});
export default Flex;

app.tsx

import React from 'react'
import Flex from './Flex';
const App = () => {
  return (
    <Flex />
  );
}
export default App;

Flex Direction

FlexDirectionBasics.tsx

import React, { useState } from "react";
import { StyleSheet, Text, TouchableOpacity, View } from "react-native";
const FlexDirectionBasics = () => {
  const [flexDirection, setflexDirection] = useState("column");
  return (
    <PreviewLayout
      label="flexDirection"
      values={["column", "row", "row-reverse", "column-reverse"]}
      selectedValue={flexDirection}
      setSelectedValue={setflexDirection}
    >
      <View
        style={[styles.box, { backgroundColor: "powderblue" }]}
      />
      <View
        style={[styles.box, { backgroundColor: "skyblue" }]}
      />
      <View
        style={[styles.box, { backgroundColor: "steelblue" }]}
      />
    </PreviewLayout>
  );
};
const PreviewLayout = ({
  label,
  children,
  values,
  selectedValue,
  setSelectedValue,
}) => (
  <View style={{ padding: 10, flex: 1 }}>
    <Text style={styles.label}>{label}</Text>
    <View style={styles.row}>
      {values.map((value: string) => (
        <TouchableOpacity
          key={value}
          onPress={() => setSelectedValue(value)}
          style={[
            styles.button,
            selectedValue === value && styles.selected,
          ]}
        >
          <Text
            style={[
              styles.buttonLabel,
              selectedValue === value && styles.selectedLabel,
            ]}
          >
            {value}
          </Text>
        </TouchableOpacity>
      ))}
    </View>
    <View style={[styles.container, { [label]: selectedValue }]}>
      {children}
    </View>
  </View>
);
const styles = StyleSheet.create({
  container: {
    flex: 1,
    marginTop: 8,
    backgroundColor: "aliceblue",
  },
  box: {
    width: 50,
    height: 50,
  },
  row: {
    flexDirection: "row",
    flexWrap: "wrap",
  },
  button: {
    paddingHorizontal: 8,
    paddingVertical: 6,
    borderRadius: 4,
    backgroundColor: "oldlace",
    alignSelf: "flex-start",
    marginHorizontal: "1%",
    marginBottom: 6,
    minWidth: "48%",
    textAlign: "center",
  },
  selected: {
    backgroundColor: "coral",
    borderWidth: 0,
  },
  buttonLabel: {
    fontSize: 12,
    fontWeight: "500",
    color: "coral",
  },
  selectedLabel: {
    color: "white",
  },
  label: {
    textAlign: "center",
    marginBottom: 10,
    fontSize: 24,
  },
});
export default FlexDirectionBasics;

注意看自定义组件的写法，以及 useState 的用法。

import React from 'react'
import FlexDirectionBasics from './FlexDirectionBasics';
const App = () => {
  return (
    <FlexDirectionBasics />
  );
}
export default App;

其他的

https://reactnative.dev/docs/flexbox