HarmonyOS 鸿蒙Next 本地数据库实现《菜谱大全》app（三）

菜谱大全的UI框架也已搭建完毕，接下来就是通过本地数据库的操作来获取相应的数据支持了。

1.首页列表获取（带分页）

//food_meau ：表的名称
/**
*


@param store 数据库实例
@param onGetFoods 获取数据成功后的回调，返回菜谱数组
@param onError
@param limit 每次获取数量限制
@param skip
*/
getFoods(store: relationalStore.RdbStore, onGetFoods: (res: Array<Food>) => void, onError?: (err: string) => void,
limit?: number, skip?: number) {
// let predicates = new relationalStore.RdbPredicates(“food_meau”)
let lim = limit <span class="hljs-number"><span class="hljs-number">10</span></span>
if (limit && skip) {
lim = limit ${limit} skip ${skip}
}

let sql = Select * from food_meau order By RANDOM() ${lim}
store.querySql(sql, (err: BusinessError, resultSet) => {
if (err == undefined) {
let foods = Array<Food>()
while (resultSet.goToNextRow()) {
foods.push(this.parseFood(resultSet))
}
onGetFoods(foods)
} else {
onError!(err.message)
}
})
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

菜谱数据的实体类

/**


菜谱数据实体类
*/
export class Food {
meauID: number = 0
name: string = ‘’
tags: string = ‘’
method: string = ‘’
img: string = ‘’
url: string = ‘’
level: string = ‘’
peopleNum: string = ‘’
taste: string = ‘’
prepareTime: string = ‘’
cookTime: string = ‘’
mainIngredient: string = ‘’ //主料
accessories: string = ‘’ //辅料
measure: string = ‘’ //步骤
techniques: string = ‘’ //技巧
scrapyTime: string = ‘’
ACL:ESObject
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

对relationalStore.ResultSet返回数据进行解析

parseFood(resultSet: relationalStore.ResultSet): Food {
let food = new Food()
food.meauID = this.parseLong(“meauID”, resultSet)
food.name = this.parseString(“name”, resultSet);
food.tags = this.parseString(“tags”, resultSet);
food.method = this.parseString(“method”, resultSet);
food.img = this.parseString(“img”, resultSet);
food.url = this.parseString(“url”, resultSet);
food.level = this.parseString(“level”, resultSet);
food.peopleNum = this.parseString(“peopleNum”, resultSet);
food.taste = this.parseString(“taste”, resultSet);
food.prepareTime = this.parseString(“prepareTime”, resultSet);
food.cookTime = this.parseString(“cookTime”, resultSet);
food.mainIngredient = this.parseString(“mainIngredient”, resultSet); //主料
food.accessories = this.parseString(“accessories”, resultSet); //辅料
food.measure = this.parseString(“measure”, resultSet); //步骤
food.techniques = this.parseString(“techniques”, resultSet); //技巧
food.scrapyTime = this.parseString(“scrapyTime”, resultSet);
return food
}
parseLong(column: string, resultSet: relationalStore.ResultSet): number {
if (resultSet.getColumnIndex(column) != -1) {
return resultSet.getLong(resultSet.getColumnIndex(column));
}
return 0
}

parseString(column: string, resultSet: relationalStore.ResultSet): string {
if (resultSet.getColumnIndex(column) != -1) {
return resultSet.getString(resultSet.getColumnIndex(column));
}
return “”
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

2.通过关键字来进行模糊搜索

/**
*


@param store
@param keyword 关键字
@param onGetFoods
@param onError
@param limit
@param skip
/
getFoodsByKeyword(store: relationalStore.RdbStore, keyword: string, onGetFoods: (res: Array<Food>) => void,
onError?: (err: string) => void, limit?: number, skip?: number) {
let lim = limit <span class="hljs-number"><span class="hljs-number">10</span></span>//限制每次取10条数据
if (limit && skip) {
lim = limit ${limit} skip ${skip}
}
let sql = Select * from food_meau where name like (<span class="hljs-string"><span class="hljs-string">"%${keyword}%"</span></span>) order By RANDOM() ${lim}
store.querySql(sql, (err: BusinessError, resultSet) => {
if (err == undefined) {
let foods = Array<Food>()
while (resultSet.goToNextRow()) {
//解析数据
foods.push(this.parseFood(resultSet))
}
onGetFoods(foods)
} else {
onError!(err.message)
}
})
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

/*
获取指定烹饪方法下的菜谱列表
@param store
@param method
@param onGetFoods
@param onError
@param limit
@param skip
*/
getFoodsByMethod(store: relationalStore.RdbStore, method: string, onGetFoods: (res: Array<Food>) => void,
onError?: (err: string) => void, limit?: number, skip?: number) {
// let predicates = new relationalStore.RdbPredicates(“food_meau”)
// store.query(predicates, (err: BusinessError, resultSet) => {
let lim = limit <span class="hljs-number"><span class="hljs-number">10</span></span>
if (limit && skip) {
lim = limit ${limit} skip ${skip}
}

let sql = Select * from food_meau where method like (<span class="hljs-string"><span class="hljs-string">"%${method}%"</span></span>) ${lim}
store.querySql(sql, (err: BusinessError, resultSet) => {
if (err == undefined) {
let foods = Array<Food>()
while (resultSet.goToNextRow()) {
foods.push(this.parseFood(resultSet))
}
onGetFoods(foods)
} else {
onError!(err.message)
}
})
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

/**


获取所有烹饪方法
@param store
@param onGetMethods
@param onError
/
getAllCookMethods(store: relationalStore.RdbStore, onGetMethods: (res: Array<string>) => void,
onError?: (err: string) => void) {
let sql = “Select * from food_meau group by method ORDER BY method DESC”
store.querySql(sql, (err: BusinessError, resultSet) => {
if (err == undefined) {
let arr: Array<string> = new Array();
while (resultSet.goToNextRow()) {
let food = this.parseFood(resultSet)
arr.push(food.method)
}
onGetMethods(arr)
} else {
onError!(err.message)
}
})
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

/*
获取所有口味
@param store
@param onGetTaste
@param onError
/
getAllTastes(store: relationalStore.RdbStore, onGetTaste: (res: Array<string>) => void,
onError?: (err: string) => void) {
let sql = “Select * from food_meau group by taste order by taste desc”
store.querySql(sql, (err: BusinessError, resultSet) => {
if (err == undefined) {
let arr: Array<string> = new Array();
while (resultSet.goToNextRow()) {
let food = this.parseFood(resultSet)
arr.push(food.taste)
}
onGetTaste(arr)
} else {
onError!(err.message)
}
})
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>

/*
根据难度获取菜谱列表
@param store
@param level
@param onGetFoods
@param onError
@param limit
@param skip
*/
getFoodsByLevel(store: relationalStore.RdbStore, level: string, onGetFoods: (res: Array<Food>) => void,
onError?: (err: string) => void, limit?: number, skip?: number) {
let lim = limit <span class="hljs-number"><span class="hljs-number">10</span></span>
if (limit && skip) {
lim = limit ${limit} skip ${skip}
}

let sql = Select * from food_meau where level like (<span class="hljs-string"><span class="hljs-string">"%${level}%"</span></span>) ${lim}
store.querySql(sql, (err: BusinessError, resultSet) => {
if (err == undefined) {
let foods = Array<Food>()
while (resultSet.goToNextRow()) {
foods.push(this.parseFood(resultSet))
}
onGetFoods(foods)
} else {
onError!(err.message)
}
})
}<button style="position: absolute; padding: 4px 8px 0px; cursor: pointer; top: 8px; right: 8px; font-size: 14px;">复制</button>