ionic 3 sqlite not return value

问题

I create provider to insert , select , delete , update data in sqlite

this my code in database.service.ts to get data

getData(){

 return  this.sqlite.create({
        name: 'data.db',
        location: 'default'
      }) 
      .then((db: SQLiteObject) => {
         db.executeSql('select * from  downloaded order by ID', {})
         .then(res => {
            for(let i = 0;i < res.row.length; i++){
                this.data.push({
                    id: res.row.item(i).id,
                    name: res.row.item(i).name,
                    url: res.row.item(i).URL
                })
            }
            return this.data;
           }).catch(e => {
            console.log(e);
            });


       })
}

and this my code in list.ts to receive the data

getData(){
this.data =  this.DB.getData();

}

but no values return

回答1:

You must publish an event with your data and listen your event in where you wait for data.

Because:

this.sqlite.create({ name: 'data.db', location: 'default' }) .then()

Is async call and dosnt return value. You should do like this:

this.events.publish('getData', dataRows);

And listen to event in where you want:

events.subscribe('getData', (data) => {
 //Do somethings
 });

来源：https://stackoverflow.com/questions/50667665/ionic-3-sqlite-not-return-value