Update ListView with onClicked [solved]

[dstudentx]

I'm using this to show contents of a database
@
import "test.js" as Logic
.......
...........
Text {
id: text1
x: 100
y: 100
text: qsTr(Logic.r)
opacity: 0
font.pixelSize: 12
}
ListView {
id: logic_rs
x: 455
y: -47
model: Logic.get_db(5,0)
delegate: Text{
text: qsTr(Logic.r)}
}
@
What I would like to do is be able to update is list with the next 5 elements from the database
Here is my failed attempt
@
onClicked:{
Logic.index_count = Logic.index_count+5
logic_rs=Logic.index_count

                }

@

My main goal is: I have a (large) list of items only 5 at a time are shown, there are next and prev button which show the next 5 items or the prev 5 items.

Here is my js for getting the data
@
var index_count = 0
var up_check = 0
var r = ""
function get_db(a, up_check) {

var db = LocalStorage.openDatabaseSync("DB5", "1.0", "The Example QML SQL!", 1000000);
db.transaction(
function(tx) {
/* tx.executeSql('CREATE TABLE IF NOT EXISTS Greeting(salutation TEXT, salutee TEXT)');
for ( var z=0; z<1000; z++){
tx.executeSql('INSERT INTO Greeting VALUES(?, ?)', [ 'Movie', z ]);
}
*/
var rs = tx.executeSql('SELECT * FROM Greeting');
r = ""
for(var i = 0; i < a; i++) {
if (i>index_count-1 && up_check ===0)
r += rs.rows.item(i).salutation + ": " + rs.rows.item(i).salutee + "\t\t"
if (up_check === 1){
var size_check =0
if (i >index_count-11 && size_check !==9) {
r += rs.rows.item(i).salutation + ": " + rs.rows.item(i).salutee + "\t\t"
size_check++
}
}
}
console.log(r);
index_count=a;
})}
@

[Gennon]

Perhaps you should try doing the paging in the SQL Query instead. Something like explained here:

http://stackoverflow.com/questions/14468586/how-paging-with-sqlite-with-millions-of-records

You could for instance use the ID (if it is increasing for every new row) as the SomeColumn value and store that in your code.

I hope this might help you out.

[dstudentx]

Thanks I'll def. be using that instead.

My main problem is I cannot get the content from the database to update on screen like in the console.

[Gennon]

OK, I'm not totally sure about this, but I think that in your ListView, the model will be constant:

@ListView {
id: logic_rs
x: 455
y: -47
model: Logic.get_db(5,0)
delegate: Text{
text: qsTr(Logic.r)}
}@

So what you need is something like:

@ListView {
id: logic_rs
x: 455
y: -47
model: someModel
delegate: Text{
text: qsTr(Logic.r)
}
}

var someModel;
function updateList(size){
someModel = Logic.get_db(size,0)
}
@

And then you run the updateList() function in the onClick or whatever.

[dstudentx]

Thanks! that makes total sense but I'm getting an error
@JavaScript declaration outside Script element@

[Gennon]

Yea, I guess it is line 11 in my example: var someModel; It was just an example, and I don't remember the best way to solve this, but you could perhaps have the var someModel in a javascript file that you include, or If I remember correctly you could just declare a property in your QML file:

@property variant someModel;@

[dstudentx]

Thank you making it a global QML worked!

but it only shows the content from the database in the terminal not the app

[Gennon]

Do you have a return statement in your function that should return the updated database model?

Im not sure if the code in the OP is up to date anymore, but I don't see a return statement.