Question

我是一个使用sqlite存储数据的离子程序。当我将数据返回到视图时，它什么都不返回。

我设置了一个服务来获取数据。它看起来像

this.todos = this.todoService.read()

在home.ts文件中，我尝试访问

这样的服务

this.todos

当我在控制台上记录{{1}}时。它没有返回任何东西。有人可以帮帮我吗？...

Answer 1

//您好， //你不能这样做.todos = this.todoService.read（）。 //您应该编写promises来从sqlite获取数据并在//组件中使用它们。 //我希望read函数在服务文件（todoService.ts）中。改变它就像//这个。

＆＃13;

//Hi,
//You cannot do this this.todos = this.todoService.read().
//You should write promises to get data from sqlite and use them in your //component.
//I expect read function is in the service file(todoService.ts). Change it like //this.

＆＃13;

    public read() {
return new Promise((resolve,reject) => {
var db = new SQLite();
        
        var query = "CREATE TABLE IF NOT EXISTS todos(id INTEGER PRIMARY KEY AUTOINCREMENT, name VARCHAR(32), datetime VARCHAR(32))";
        db.create({
          name: "data.db",
          location: "default"
        }).then((db1: SQLiteObject) => {
          db1.executeSql(query,[])
          .then((res) => {
            let todos = [];
            if(res.rows.length > 0 ) {
              todos.push(res.rows.item(0))
            }
            resolve(todos)
          },(error) => {
            reject(error);
          });
})

}
//  The promise returns an array of objects


In the page component 
// declare this
 public itemList : Array<Object>;
// In the constructor
this.itemList = [];

this.todoService.read().then((result) => {
this.itemList = <Array<Object>> result;
// you will get the retrieved data from sqlite from this array
console.log(this.itemList)
})
)


// This should work Please update me in case of any issues

＆＃13;

如何使用Ionic sqlite返回返回数据

1 个答案: