import {ohosData} from '@ohosdata/sdk';

const context = ohos.abilityManager.getCurrent = () => {return null};

export default class MemoApp extends React.Component {
    constructor(props) {
        super(props);

创建云端数据库对象
        this.db = ohosData.createCloudDB(context, 'memo');
在数据库中创建备忘录条目表
        this.memoTable = this.db.defineTable('memo', {
            id: 'integer',
            content: 'text',
            createTime: 'date',
        });
同步云端数据到本地
        this.db.sync();

        this.state = {
用于存储备忘录条目的状态
        };
    }

    componentDidMount() {
监听云端数据变化，实现数据实时同步和更新
        this.memoTable.onDataChange(() => {
            this.setState({
查询数据库中的备忘录条目
            });
        });
    }

    componentWillUnmount() {
组件卸载时，取消数据监听
        this.memoTable.offDataChange();
    }

    addMemo(content) {
添加备忘录条目到云数据库
        this.memoTable.insert({
            id: Date.now(),
            content: content,
            createTime: new Date()
        });
        this.db.sync();
    }

    deleteMemo(id) {
删除指定id的备忘录条目
        this.memoTable.remove({id: id});
        this.db.sync();
    }

    render() {
        return (
渲染备忘录应用界面
            <div>
                <h1>Memo App</h1>
                <MemoList memos={this.state.memos} onDelete={this.deleteMemo} />
                <MemoInput onAdd={this.addMemo} />
            </div>
        );
    }
}

class MemoList extends React.Component {
    render() {
        return (
            <ul>
                {this.props.memos.map(memo => (
                    <li key={memo.id}>
                        {memo.content}
                        <button onClick={() => this.props.onDelete(memo.id)}>Delete</button>
                    </li>
                ))}
            </ul>
        );
    }
}

class MemoInput extends React.Component {
    constructor(props) {
        super(props);
        this.state = {content: ''};
    }

    handleInputChange(event) {
        this.setState({content: event.target.value});
    }

    handleAddClick() {
        this.props.onAdd(this.state.content);
        this.setState({content: ''});
    }

    render() {
        return (
            <div>
                <input type="text" value={this.state.content} onChange={event => this.handleInputChange(event)} placeholder="Enter your memo" />
                <button onClick={() => this.handleAddClick()}>Add</button>
            </div>
        );
    }
}