103 строки
2.7 KiB
JavaScript
103 строки
2.7 KiB
JavaScript
/**
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* Copyright (c) 2015-present, Facebook, Inc.
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*
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* This source code is licensed under the MIT license found in the
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* LICENSE file in the root directory of this source tree.
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*
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* @format
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* @flow
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*/
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'use strict';
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var React = require('react');
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var ReactNative = require('react-native');
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var {AsyncStorage, PickerIOS, Text, View} = ReactNative;
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var PickerItemIOS = PickerIOS.Item;
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var STORAGE_KEY = '@AsyncStorageExample:key';
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var COLORS = ['red', 'orange', 'yellow', 'green', 'blue'];
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class BasicStorageExample extends React.Component<{}, $FlowFixMeState> {
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state = {
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selectedValue: COLORS[0],
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messages: [],
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};
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componentDidMount() {
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this._loadInitialState().done();
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}
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_loadInitialState = async () => {
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try {
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var value = await AsyncStorage.getItem(STORAGE_KEY);
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if (value !== null) {
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this.setState({selectedValue: value});
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this._appendMessage('Recovered selection from disk: ' + value);
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} else {
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this._appendMessage('Initialized with no selection on disk.');
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}
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} catch (error) {
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this._appendMessage('AsyncStorage error: ' + error.message);
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}
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};
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render() {
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var color = this.state.selectedValue;
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return (
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<View>
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<PickerIOS selectedValue={color} onValueChange={this._onValueChange}>
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{COLORS.map(value => (
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<PickerItemIOS key={value} value={value} label={value} />
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))}
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</PickerIOS>
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<Text>
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{'Selected: '}
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<Text style={{color}}>{this.state.selectedValue}</Text>
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</Text>
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<Text> </Text>
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<Text onPress={this._removeStorage}>
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Press here to remove from storage.
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</Text>
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<Text> </Text>
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<Text>Messages:</Text>
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{this.state.messages.map(m => <Text key={m}>{m}</Text>)}
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</View>
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);
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}
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_onValueChange = async selectedValue => {
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this.setState({selectedValue});
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try {
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await AsyncStorage.setItem(STORAGE_KEY, selectedValue);
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this._appendMessage('Saved selection to disk: ' + selectedValue);
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} catch (error) {
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this._appendMessage('AsyncStorage error: ' + error.message);
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}
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};
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_removeStorage = async () => {
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try {
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await AsyncStorage.removeItem(STORAGE_KEY);
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this._appendMessage('Selection removed from disk.');
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} catch (error) {
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this._appendMessage('AsyncStorage error: ' + error.message);
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}
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};
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_appendMessage = message => {
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this.setState({messages: this.state.messages.concat(message)});
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};
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}
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exports.title = 'AsyncStorage';
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exports.description = 'Asynchronous local disk storage.';
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exports.examples = [
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{
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title: 'Basics - getItem, setItem, removeItem',
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render(): React.Element<any> {
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return <BasicStorageExample />;
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},
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},
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];
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