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Backend API
import React, { useCallback, useRef, useState } from 'react';
import ScrollView, { ScrollViewTypes } from 'devextreme-react/scroll-view';
import SelectBox from 'devextreme-react/select-box';
import CheckBox, { CheckBoxTypes } from 'devextreme-react/check-box';
import service from './data.ts';
type UpdateContentArgs = ScrollViewTypes.PullDownEvent | ScrollViewTypes.ReachBottomEvent;
const showScrollBarModeLabel = { 'aria-label': 'Show Scrollbar Mode' };
let updateContentTimer;
const App = () => {
const [showScrollBarMode, setShowScrollBarMode] = useState<ScrollViewTypes.Properties['showScrollbar']>('onScroll');
const [pullDown, setPullDown] = useState(false);
const [scrollByContent, setScrollByContent] = useState(true);
const [scrollByThumb, setScrollByThumb] = useState(true);
const [content, setContent] = useState(service.getContent());
const scrollViewRef = useRef(null);
const updateContent = useCallback((args: UpdateContentArgs, eventName: string) => {
const updateContentText = `\n Content has been updated on the ${eventName} event.\n\n`;
if (updateContentTimer) {
clearTimeout(updateContentTimer);
}
updateContentTimer = setTimeout(() => {
setContent(eventName === 'PullDown' ? updateContentText + content : content + updateContentText);
args.component.release(false);
}, 500);
}, [content, setContent]);
const updateTopContent = useCallback((args: ScrollViewTypes.PullDownEvent) => {
updateContent(args, 'PullDown');
}, [updateContent]);
const updateBottomContent = useCallback((args: ScrollViewTypes.ReachBottomEvent) => {
updateContent(args, 'ReachBottom');
}, [updateContent]);
const pullDownValueChanged = useCallback((args: CheckBoxTypes.ValueChangedEvent) => {
setPullDown(args.value);
}, [setPullDown]);
const reachBottomValueChanged = useCallback((args: CheckBoxTypes.ValueChangedEvent) => {
scrollViewRef.current.instance().option('onReachBottom', args.value ? updateBottomContent : null);
}, [updateBottomContent]);
return (
<div id="scrollview-demo">
<ScrollView
id="scrollview"
ref={scrollViewRef}
reachBottomText="Updating..."
scrollByContent={scrollByContent}
bounceEnabled={pullDown}
onReachBottom={updateBottomContent}
onPullDown={updateTopContent}
showScrollbar={showScrollBarMode}
scrollByThumb={scrollByThumb}
>
<div className="text-content">{content}</div>
</ScrollView>
<div className="options">
<div className="caption">Options</div>
<div className="option">
<span>Show scrollbar: </span>
<SelectBox
items={showScrollbarModes}
valueExpr="value"
inputAttr={showScrollBarModeLabel}
displayExpr="text"
value={showScrollBarMode}
onValueChange={setShowScrollBarMode}
/>
</div>
<div className="option">
<CheckBox
text="Update content on the ReachBottom event"
defaultValue={true}
onValueChanged={reachBottomValueChanged}
/>
</div>
<div className="option">
<CheckBox
text="Update content on the PullDown event"
value={pullDown}
onValueChanged={pullDownValueChanged}
/>
</div>
<div className="option">
<CheckBox
text="Scroll by content"
value={scrollByContent}
onValueChange={setScrollByContent}
/>
</div>
<div className="option">
<CheckBox
text="Scroll by thumb"
value={scrollByThumb}
onValueChange={setScrollByThumb}
/>
</div>
</div>
</div>
);
};
const showScrollbarModes = [
{
text: 'On Scroll',
value: 'onScroll',
},
{
text: 'On Hover',
value: 'onHover',
},
{
text: 'Always',
value: 'always',
},
{
text: 'Never',
value: 'never',
},
];
export default App;
import React, { useCallback, useRef, useState } from 'react';
import ScrollView from 'devextreme-react/scroll-view';
import SelectBox from 'devextreme-react/select-box';
import CheckBox from 'devextreme-react/check-box';
import service from './data.js';
const showScrollBarModeLabel = { 'aria-label': 'Show Scrollbar Mode' };
let updateContentTimer;
const App = () => {
const [showScrollBarMode, setShowScrollBarMode] = useState('onScroll');
const [pullDown, setPullDown] = useState(false);
const [scrollByContent, setScrollByContent] = useState(true);
const [scrollByThumb, setScrollByThumb] = useState(true);
const [content, setContent] = useState(service.getContent());
const scrollViewRef = useRef(null);
const updateContent = useCallback(
(args, eventName) => {
const updateContentText = `\n Content has been updated on the ${eventName} event.\n\n`;
if (updateContentTimer) {
clearTimeout(updateContentTimer);
}
updateContentTimer = setTimeout(() => {
setContent(
eventName === 'PullDown' ? updateContentText + content : content + updateContentText,
);
args.component.release(false);
}, 500);
},
[content, setContent],
);
const updateTopContent = useCallback(
(args) => {
updateContent(args, 'PullDown');
},
[updateContent],
);
const updateBottomContent = useCallback(
(args) => {
updateContent(args, 'ReachBottom');
},
[updateContent],
);
const pullDownValueChanged = useCallback(
(args) => {
setPullDown(args.value);
},
[setPullDown],
);
const reachBottomValueChanged = useCallback(
(args) => {
scrollViewRef.current
.instance()
.option('onReachBottom', args.value ? updateBottomContent : null);
},
[updateBottomContent],
);
return (
<div id="scrollview-demo">
<ScrollView
id="scrollview"
ref={scrollViewRef}
reachBottomText="Updating..."
scrollByContent={scrollByContent}
bounceEnabled={pullDown}
onReachBottom={updateBottomContent}
onPullDown={updateTopContent}
showScrollbar={showScrollBarMode}
scrollByThumb={scrollByThumb}
>
<div className="text-content">{content}</div>
</ScrollView>
<div className="options">
<div className="caption">Options</div>
<div className="option">
<span>Show scrollbar: </span>
<SelectBox
items={showScrollbarModes}
valueExpr="value"
inputAttr={showScrollBarModeLabel}
displayExpr="text"
value={showScrollBarMode}
onValueChange={setShowScrollBarMode}
/>
</div>
<div className="option">
<CheckBox
text="Update content on the ReachBottom event"
defaultValue={true}
onValueChanged={reachBottomValueChanged}
/>
</div>
<div className="option">
<CheckBox
text="Update content on the PullDown event"
value={pullDown}
onValueChanged={pullDownValueChanged}
/>
</div>
<div className="option">
<CheckBox
text="Scroll by content"
value={scrollByContent}
onValueChange={setScrollByContent}
/>
</div>
<div className="option">
<CheckBox
text="Scroll by thumb"
value={scrollByThumb}
onValueChange={setScrollByThumb}
/>
</div>
</div>
</div>
);
};
const showScrollbarModes = [
{
text: 'On Scroll',
value: 'onScroll',
},
{
text: 'On Hover',
value: 'onHover',
},
{
text: 'Always',
value: 'always',
},
{
text: 'Never',
value: 'never',
},
];
export default App;
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.tsx';
ReactDOM.render(
<App />,
document.getElementById('app'),
);
let longText = '';
for (let i = 0; i < 10; i += 1) {
longText += 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\n\n';
}
export default {
getContent() {
return longText;
},
};
window.exports = window.exports || {};
window.config = {
transpiler: 'ts',
typescriptOptions: {
module: 'system',
emitDecoratorMetadata: true,
experimentalDecorators: true,
jsx: 'react',
},
meta: {
'react': {
'esModule': true,
},
'typescript': {
'exports': 'ts',
},
'devextreme/time_zone_utils.js': {
'esModule': true,
},
'devextreme/localization.js': {
'esModule': true,
},
'devextreme/viz/palette.js': {
'esModule': true,
},
},
paths: {
'npm:': 'https://unpkg.com/',
},
defaultExtension: 'js',
map: {
'ts': 'npm:plugin-typescript@4.2.4/lib/plugin.js',
'typescript': 'npm:typescript@4.2.4/lib/typescript.js',
'react': 'npm:react@17.0.2/umd/react.development.js',
'react-dom': 'npm:react-dom@17.0.2/umd/react-dom.development.js',
'prop-types': 'npm:prop-types@15.8.1/prop-types.js',
'rrule': 'npm:rrule@2.6.4/dist/es5/rrule.js',
'luxon': 'npm:luxon@1.28.1/build/global/luxon.min.js',
'es6-object-assign': 'npm:es6-object-assign@1.1.0',
'devextreme': 'npm:devextreme@24.1.6/cjs',
'devextreme-react': 'npm:devextreme-react@24.1.6/cjs',
'jszip': 'npm:jszip@3.10.1/dist/jszip.min.js',
'devextreme-quill': 'npm:devextreme-quill@1.7.1/dist/dx-quill.min.js',
'devexpress-diagram': 'npm:devexpress-diagram@2.2.11/dist/dx-diagram.js',
'devexpress-gantt': 'npm:devexpress-gantt@4.1.56/dist/dx-gantt.js',
'@devextreme/runtime': 'npm:@devextreme/runtime@3.0.13',
'inferno': 'npm:inferno@7.4.11/dist/inferno.min.js',
'inferno-compat': 'npm:inferno-compat/dist/inferno-compat.min.js',
'inferno-create-element': 'npm:inferno-create-element@7.4.11/dist/inferno-create-element.min.js',
'inferno-dom': 'npm:inferno-dom/dist/inferno-dom.min.js',
'inferno-hydrate': 'npm:inferno-hydrate@7.4.11/dist/inferno-hydrate.min.js',
'inferno-clone-vnode': 'npm:inferno-clone-vnode/dist/inferno-clone-vnode.min.js',
'inferno-create-class': 'npm:inferno-create-class/dist/inferno-create-class.min.js',
'inferno-extras': 'npm:inferno-extras/dist/inferno-extras.min.js',
'devextreme-cldr-data': 'npm:devextreme-cldr-data@1.0.3',
// SystemJS plugins
'plugin-babel': 'npm:systemjs-plugin-babel@0.0.25/plugin-babel.js',
'systemjs-babel-build': 'npm:systemjs-plugin-babel@0.0.25/systemjs-babel-browser.js',
// Prettier
'prettier/standalone': 'npm:prettier@2.8.8/standalone.js',
'prettier/parser-html': 'npm:prettier@2.8.8/parser-html.js',
},
packages: {
'devextreme': {
defaultExtension: 'js',
},
'devextreme-react': {
main: 'index.js',
},
'devextreme/events/utils': {
main: 'index',
},
'devextreme/localization/messages': {
format: 'json',
defaultExtension: 'json',
},
'devextreme/events': {
main: 'index',
},
'es6-object-assign': {
main: './index.js',
defaultExtension: 'js',
},
},
packageConfigPaths: [
'npm:@devextreme/*/package.json',
'npm:@devextreme/runtime@3.0.13/inferno/package.json',
],
babelOptions: {
sourceMaps: false,
stage0: true,
react: true,
},
};
System.config(window.config);
import React from 'react';
import ReactDOM from 'react-dom';
import App from './App.js';
ReactDOM.render(<App />, document.getElementById('app'));
let longText = '';
for (let i = 0; i < 10; i += 1) {
longText
+= 'Lorem ipsum dolor sit amet, consectetur adipisicing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.\n\n';
}
export default {
getContent() {
return longText;
},
};
<!DOCTYPE html>
<html lang="en">
<head>
<title>DevExtreme Demo</title>
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=5.0" />
<link rel="stylesheet" type="text/css" href="https://cdn3.devexpress.com/jslib/24.1.6/css/dx.light.css" />
<link rel="stylesheet" type="text/css" href="styles.css" />
<script src="https://unpkg.com/core-js@2.6.12/client/shim.min.js"></script>
<script src="https://unpkg.com/systemjs@0.21.3/dist/system.js"></script>
<script type="text/javascript" src="config.js"></script>
<script type="text/javascript">
System.import("./index.tsx");
</script>
</head>
<body class="dx-viewport">
<div class="demo-container">
<div id="app"></div>
</div>
</body>
</html>
#scrollview-demo {
min-height: 550px;
}
.text-content {
white-space: pre-wrap;
}
#scrollview {
height: auto;
position: absolute;
top: 0;
bottom: 300px;
padding: 20px;
}
.options {
padding: 20px;
background-color: rgba(191, 191, 191, 0.15);
position: absolute;
bottom: 0;
left: 0;
right: 0;
}
.caption {
font-size: 18px;
font-weight: 500;
}
.option {
margin-top: 10px;
}
.option > span {
position: relative;
top: 2px;
margin-right: 10px;
}
.option > .dx-selectbox {
display: inline-block;
vertical-align: middle;
max-width: 340px;
width: 100%;
}