带你从零学ReactNative开发跨平台App开发（十一）

 ReactNative跨平台开发系列教程：

带你从零学ReactNative开发跨平台App开发（一）

带你从零学ReactNative开发跨平台App开发（二）

带你从零学ReactNative开发跨平台App开发（三）

带你从零学ReactNative开发跨平台App开发（四）

带你从零学ReactNative开发跨平台App开发（五）

带你从零学ReactNative开发跨平台App开发（六）

带你从零学ReactNative开发跨平台App开发（七）

hot：更多>>

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上篇说要来点真干货，由于接口没有整理好，我打算整理好接口直接部署到服务器上，这样大家可以一起使用，很遗憾，还没有整理好，不过，今天依然来点干货，只不过不是太干！

废话不多说，开始撸码，你准备好了吗？

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这篇主要利用expo上集成的sqllite数据，以及一些缓存操作，做一个简单类型的备忘录！

主要用到依赖有

    "expo": "^23.0.4",
    "pubsub-js": "^1.5.7",
    "react": "16.0.0",
    "react-native": "0.50.3",
    "react-navigation": "^1.0.0-beta.22"

该项目源代码，全部推到github，点击这里获取！

这个demo虽然小，但是灵活的控制了数据流。希望大家可以有所收获。

犹豫本项目用到了SqlLite，在此我想喷一些那些搞移动端之想着掉接口的屌丝们！

下面简单介绍一些代码：（能把 这写代码看透彻的人，我给你点赞！）

//import liraries
import React, { Component } from 'react';
import {
    View,
    Text,
    StyleSheet,
    TouchableOpacity,
    ListView,
} from 'react-native';
import PubSub from 'pubsub-js';
import MainItem from './MainItem';
import TodoManager from '../DataServer/TodoManager';
import AddTodo from './AddTodo';
import Footer from '../Component/Footer';
// create a component
class MainView extends Component {
    static navigationOptions = {
        title: '备忘录',
        headerStyle: ({
            backgroundColor: "#0EABE8",
            elevation: 0,
        }),
        headerTitleStyle: ({
            alignSelf: 'center'
        }),
        headerLeft: (
            <TouchableOpacity onPress={() => {
                PubSub.publish('all');
            }}>
                <Text>全选</Text>
            </TouchableOpacity>
        ),
        headerRight: (
            <TouchableOpacity onPress={() => {
                PubSub.publish('add');
            }}>
                <Text>添加</Text>
            </TouchableOpacity>
        )
    }
    componentDidMount() {
        PubSub.subscribe('all', () => {
            TodoManager.selectAll();
        });
        PubSub.subscribe('add', () => {
            this.props.navigation.navigate('AddTodo');
        });
        TodoManager.setListener((todo) => {
            this.setState({
                ds: this.state.ds.cloneWithRows(todo),
            });
        });
        TodoManager.setFinishListener((total) => {
            this.setState({
                selectCount: total,
            });
        });
        TodoManager.getTodoInfo();

    }
    constructor(props) {
        super(props);
        const ds = new ListView.DataSource({ rowHasChanged: (r1, r2) =>  r1 !== r2  });
        this.state = {
            ds: ds.cloneWithRows([]),
            isSelect: false,
            selectCount: 0,
        }
    }
    render() {
        return (
            <View style={styles.container}>
                <ListView
                    dataSource={this.state.ds}
                    renderRow={(rowData) => {
                        console.log('===========rowData=========================');
                        console.log(rowData);
                        console.log('====================================');
                        return (
                            <View>
                                <MainItem
                                    {...rowData}
                                    clickSelect={(id) => {
                                        console.log('====================================');
                                        console.log('点击了id' + id);
                                        console.log('====================================');
                                        TodoManager.singleSelect(id);
                                    }} />
                                <Text>{rowData.finish}</Text>
                            </View>

                        );
                    }}
                    enableEmptySections={true}
                />

                <Footer selectCount={this.state.selectCount} />
            </View>
        );
    }
}

// define your styles
const styles = StyleSheet.create({
    container: {
        flex: 1,
        justifyContent: 'center',
        alignItems: 'center',
        backgroundColor: '#fff',
    },
});

//make this component available to the app
export default MainView;

关于操作SqlLite的Manager

import { SQLite } from 'expo';
class TodoManager {
    constructor() {
        this.db = SQLite.openDatabase('todoDB4');
        this.db.transaction((tx) => {
            const sql = "create table 'main'.'todo' ('id' integer not null primary key autoincrement,'name' text,'content' text,'finish' integer)";
            tx.executeSql(sql, null, (tx, result) => {
                console.log('====================================');
                console.log('创建表成功');
                console.log('====================================');
            }, (tx, error) => {
                console.log('====================================');
                console.log('创建表失败' + error);
                console.log('====================================');
            });
        });
    }

    setListener(listener) {
        this.listener = listener;
    }

    setFinishListener(listener) {
        this.finishListener = listener;
    }

    getTodoInfo(callBack) {
        console.log('====================================');
        console.log('bbbbb');
        console.log('====================================');
        this.db.transaction((tx) => {
            const sql = 'select * from todo';
            tx.executeSql(sql, null, (tx, result) => {
                const todos = result.rows._array;
                console.log('=============todostodos=======================');
                console.log(todos);
                console.log('====================================');
                
                //监听选中与否的变量变化
                let selectCount = 0;
                todos.map((value) => {
                    if (value.finish == 1) {
                        selectCount++;
                    }
                });
                //巧妙思路的变化
                if (callBack) {
                    callBack(todos);
                }
                if (this.listener) {
                    console.log('====================================');
                    console.log('this.listener');
                    console.log('====================================');
                    this.listener(todos);
                }
                //回传过去
                this.finishListener(selectCount);
            }, (tx, error) => {
                console.log('====================================');
                console.log('查询失败' + error);
                console.log('====================================');
                //巧妙思路的变化
                if (callBack) {
                    callBack([]);
                }
                if (this.listener) {
                    this.listener([]);
                }
            });
        });
    }

    addTodoInfo(info, callBack) {
        this.db.transaction((tx) => {
            const sql = `insert into todo(name,content,finish) values('${info.name}','${info.content}',0)`;
            tx.executeSql(sql, null, (tx, result) => {
                console.log('====================================');
                console.log('添加成功');
                console.log('====================================');
                this.getTodoInfo();
                if (callBack) {
                    callBack(true);
                }

            }, (tx, error) => {
                console.log('====================================');
                console.log('添加失败' + error);
                console.log('====================================');
                if (callBack) {
                    callBack(false);
                }
            });
        });
    }

    delTodoInfo() {
        // this.db.transaction((tx) => {
        //     const ids = info.id.join(',');
        //     const sql = `delete from todo where id in (${ids})`;
        //     tx.executeSql(sql, null, (tx, result) => {
        //         console.log('====================================');
        //         console.log('删除成功');
        //         console.log('====================================');
        //         if (callBack) {
        //             callBack(true);
        //         }
        //         this.getTodoInfo();
        //     }, (tx, error) => {
        //         console.log('====================================');
        //         console.log('删除失败' + error);
        //         console.log('====================================');
        //         if (callBack) {
        //             callBack(false);
        //         }
        //     });

        // });
        this.db.transaction((tx) => {
            const sql = 'delete from todo where finish = 1';
            tx.executeSql(sql, null, (tx, resultSet) => {
                console.log('删除成功');
                this.getTodoInfo();
            })
        })
    }

    //全选
    selectAll() {
        this.db.transaction((tx) => {
            const sql = 'select * from todo';
            tx.executeSql(sql, null, (tx, result) => {
                const array = result.rows._array;
                let length = array.length;
                let slength = 0;
                array.map((value, key) => {
                    if (value.finish == 1) {
                        slength++;
                    }
                });
                if (slength == length) {
                    //取消全选
                    const sql = 'update todo set finish=0';
                    tx.executeSql(sql, null, (tx, resultSet) => {
                        if (resultSet) {
                            this.getTodoInfo();
                        }
                    }, (tx, error) => {
                        console.log('====================================');
                        console.log('取消全选失败' + error);
                        console.log('====================================');
                    });

                } else {
                    //全选
                    const sql = 'update todo set finish=1';
                    tx.executeSql(sql, null, (tx, resultSet) => {
                        if (resultSet) {
                            this.getTodoInfo();
                        }
                    }, (tx, error) => {
                        console.log('====================================');
                        console.log('全选失败' + error);
                        console.log('====================================');
                    });
                }

            }, (tx, error) => {
                console.log('====================================');
                console.log('全选失败' + error);
                console.log('====================================');
            });
        });
    }

    //单选
    singleSelect(id) {
        //先根据传过来的id查询一下
        this.db.transaction((tx) => {
            const sql = `select * from todo where id=${id}`;
            tx.executeSql(sql, null, (tx, resultSet) => {
                //修改其状态
                const todo = resultSet.rows._array[0];
                const finish = todo.finish ? 0 : 1;//修改
                const sql = `update todo set finish=${finish} where id=${id}`;
                tx.executeSql(sql, null, (tx, resultSet) => {
                    console.log('==============aaaa======================');
                    console.log('aaaa');
                    console.log('====================================');
                    this.getTodoInfo();
                })
            }, (tx, error) => {
                console.log('====================================');
                console.log('单选失败' + error);
                console.log('====================================');
            });
        });

    }

}
export default new TodoManager();

细节就不详细介绍了，代码github上自己好好研究！

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后续文章持续更新，敬请期待！

文章为作者原创，转载请注明出处。