react-native/RNTester/js/AsyncStorageExample.js

112 lines
2.8 KiB
JavaScript

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