SQLite db doesn't populate QML ComboBox

[gabor53]

Hi,
I am trying to populate a ComboBox using an SQLite db. The code I currently does't give any error messages. When I click on the combobox I get a white rectangle with nothing in it. Here is the code:
main.qml:

import QtQuick 2.0
import VPlayApps 1.0
import QtQuick.Controls 1.4
import QtQuick.Controls 2.2
import QtQuick.Controls.Styles 1.4
import QtQuick.Layouts 1.3
import QtQuick.LocalStorage 2.0
import QtQml.Models 2.3
import "Database.js" as JS
import "Dropboxes.js" as DB

App {
    Rectangle {
        id: root
        color: "#a1d9ea"
        anchors.fill: parent
        focus: false

        Text {
            id: title
            text: "Combobox"
            font.pixelSize: 25
            anchors.horizontalCenter: root.horizontalCenter
            anchors.top: root.top
            anchors.topMargin: 30
        }

        ComboBox {
            id: whatCombo
            anchors.horizontalCenter: title.horizontalCenter
            anchors.top: title.bottom
            anchors.topMargin: 30
            editable: true
            textRole: "text"
            height: 50
            width: 230
            model: ListModel {
                id: listModel
            }

            delegate: ItemDelegate {
                width: whatCombo.width
                height: whatCombo.height
                text: model.text
                font.pixelSize: 18
                font.weight: whatCombo.currentIndex === model.index ? Font.DemiBold : Font
            }
        }

        Component.onCompleted: {
            var db = JS.dbGetHandle()
            db.transaction(function (tx) {
                var results = tx.executeSql(
                            'SELECT what FROM dropboxWhatIs order by what desc')
                for (var i = 0; i < results.rows.length; i++) {
                    listModel.append({
                                         id: results.rows.item(i).what,
                                         checked: ""
                                     })
                }
            })
        }
    }
}

Database.js:

function dbInit() {
    var db = LocalStorage.openDatabaseSync("FolkFriends", "",
                                           "Friend info", 1000000)
    try {
        db.transaction(function (tx) {
            tx.executeSql(
                        'CREATE TABLE IF NOT EXISTS dropboxWhatIs (what text)')
        })
    } catch (err) {
        console.log("Error creating table in database: " + err)
    }
    ;
}

function dbGetHandle() {
    try {
        var db = LocalStorage.openDatabaseSync("FolkFriends", "",
                                               "Friend info", 1000000)
    } catch (err) {
        console.log("Error opening database: " + err)
    }
    return db
}

function dbReadAll() {
    var db = dbGetHandle()
    db.transaction(function (tx) {
        var results = tx.executeSql(
                    'SELECT what FROM dropboxWhatIs order by what desc')
        for (var i = 0; i < results.row.length; i++) {
            listModel.append({
                                 what: results.rows.item(i).what,
                                 checked: " "
                             })
        }
    })
}

function dbInsert(Pwhat) {
    var db = dbGetHandle()
    var rowid = 0
    db.transaction(function (tx) {
        tx.executeSql('INSERT INTO dropboxWhatIs VALUES(?)', [Pwhat])
        var results = tx.executeSql('SELECT last_insert_rowid()')
        rowid = result.insertId
    })
}

function dbInsert(Pwhat) {
    var db = dbGetHandle()
    var rowid = 0
    db.transaction(function (tx) {
        tx.executeSql('INSERT INTO dropboxWhatIs VALUES (?)'[Pwhat])
        var results = tx.executeSql('SELECT last_insert_rowid()')
        rowid = result.inserted.Id
    })
    return rowid
}

What am I missing? Thank you for your help.

[AndyS]

Hi @gabor53,

Have you checked to see if it returns anything for the select query? To rule out the problem being that the query returns nothing as opposed to it not getting into the combobox?

[Diracsbracket]

@gabor53 said in SQLite db doesn't populate QML ComboBox:

You do:

delegate: ItemDelegate {
         text: model.text
}

but you define your model as:

listModel.append({
     id: results.rows.item(i).what,
     checked: " "
 })

and a bit further as

listModel.append({
    what: results.rows.item(i).what,
    checked: " "
})

So, not only do you try to use different field names in your model when you add the elements (id vs what) which is not allowed, but also your delegate uses the non-defined model property 'text'.

[gabor53]

Hi @Diracsbracket ,
Thank you. It works now.

[Vahid KaraBey]

Would you please tell how do you solve the problem?