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Settings

本文档贡献者：sunnylqm(100.00%)

Settings是对NSUserDefaults的封装。它是 iOS 平台上的一种持久的键值对存储。

示例

import React, { useState } from "react";
import { Button, Settings, StyleSheet, Text, View } from "react-native";

const App = () => {
  const [data, setData] = useState(Settings.get("data"));

  const storeData = data => {
    Settings.set(data);
    setData(Settings.get("data"));
  };

  return (
    <View style={styles.container}>
      <Text>Stored value:</Text>
      <Text style={styles.value}>{data}</Text>
      <Button
        onPress={() => storeData({ data: "React" })}
        title="Store 'React'"
      />
      <Button
        onPress={() => storeData({ data: "Native" })}
        title="Store 'Native'"
      />
    </View>
  );
};

const styles = StyleSheet.create({
  container: {
    flex: 1,
    justifyContent: "center",
    alignItems: "center"
  },
  value: {
    fontSize: 24,
    marginVertical: 12
  }
});

export default App;

---

Reference

Methods

clearWatch()

static clearWatch(watchId: number)

watchId is the number returned by watchKeys() when the subscription was originally configured.

get()

static get(key: string): mixed

Get the current value for a given key in NSUserDefaults.

---

set()

static set(settings: object)

Set one or more values in NSUserDefaults.

---

watchKeys()

static watchKeys(keys: string | array<string>, callback: function): number

Subscribe to be notified when the value for any of the keys specified by the keys parameter has been changed in NSUserDefaults. Returns a watchId number that may be used with clearWatch() to unsubscribe.

Note: watchKeys() by design ignores internal set() calls and fires callback only on changes preformed outside of React Native code.