ionic 2 sqlite run on android : cannot read property executeSql of undefined - sqlite

Question

I write a test tabs ionic 2 app use sqlite plugin. I wrapper the sqlite as provier:
import { SQLite, Device } from 'ionic-native';
import { Injectable } from '#angular/core';
import { Http } from '#angular/http';
import 'rxjs/add/operator/map';
/*
Generated class for the SqliteHelper provider.
See https://angular.io/docs/ts/latest/guide/dependency-injection.html
for more info on providers and Angular 2 DI.
*/
#Injectable()
export class SqliteHelper {
public db : SQLite;
public log : string = "";
constructor(public http: Http) {
console.log('Hello SqliteHelper Provider');
}
public initDb() {
this.db = new SQLite();
this.log += "openDatabase。。。";
// if (Device.device.platform)
this.db.openDatabase({
name: "data.db",
location: "default"
}).then((data) =>{
this.log += ("open ok " + JSON.stringify(data));
}, (err) => {
this.log += ("open err " + err.message + " " + JSON.stringify(err));
});
}
public executeSql(statement: string, parms:any) {
return this.db.executeSql(statement, parms);
}
}
And init sqlitehelper in app.components :
constructor(platform: Platform, sqliteHelper : SqliteHelper, events: Events) {
platform.ready().then(() => {
// Okay, so the platform is ready and our plugins are available.
// Here you can do any higher level native things you might need.
sqliteHelper.initDb();
events.publish("sqlite:inited", null);
StatusBar.styleDefault();
Splashscreen.hide();
});
}
And I load data from the first tabs page in constructor with platform.ready, run it on android will cause err: cannot read property executeSql of undefined.
If I load data from a button click, it's ok. or I put the loaddata to the second page's constructor, it's ok too.why?who can help me , I want to put code to the first page and load data at page started.

Answer 1

I had the same error when i try to insert in database for that reason i added "executeSql" function inside transaction:
this.database.openDatabase({
name: "sis.db",
location: "default"
}).then(() => {
this.database.executeSql("CREATE TABLE IF NOT EXISTS profile(id integer primary key autoincrement NOT NULL ,name Text NOT NULL)", []).then((data) => { console.log('profile table created'); }, (error) => { console.log('Unable to create table profile'); })
this.database.transaction(tr => { tr.executeSql("insert into profile(id,name) values(12,'Ibrahim')", []); }).then(d => { console.log('Data inserted ya hima'); }, err => { console.error('unable to insert data into profile table'); });
this.database.executeSql("select id from profile", []).then(d => { console.log('inserted id=' + d.rows.item(0).app_id); }, err => { console.error('unable to get ID from profile table'); });
}, (error) => {console.error(error); }
);