How to access QSqlRelationalModel from function?
-
This is my header:
class RepairDevices: public QMainWindow { Q_OBJECT public: RepairDevices(); private slots: void refresh_devices_search_tbl(); private: void setupDevices(); void setupRepairs(); Ui::RepairDevices ui; QSqlRelationalTableModel *repairsmodel;
This is my Source file:
RepairDevices::RepairDevices() { repairsmodel = new QSqlRelationalTableModel(this); } void refresh_devices_search_tbl(){ Ui::RepairDevices *ui; QString sn = ui->sn_search_txt->toPlainText(); repairsmodel->setFilter("id>76"); }
But It's ending with Error application ended unexpectedly.
Obviously, I 'm doing something very won here.
Which is the correct way to do it?
So I 'll be able to make repairsmodel->setFilter work in my function? -
Hi
void refresh_devices_search_tbl(){
Ui::RepairDevices *ui; <<<< what is this ? looks nasty, Did you even allocate it ? Looks bad and wrong to me :)
}why is refresh_devices_search_tbl not member of RepairDevices ?
If it was then repairsmodel is available to it.
RepairDevices::refresh_devices_search_tbl
-
The 'Ui::RepairDevices *ui' I put it for someone to norice it and tell me if it's correct.
I made the function a private member, so now I have access to ui and repairsmodel.
But when the execution goes to repairsmodel->setFilter("id>76") (this is in the function), the application breaks down.
"The program has unexpectedly finished."I tried in debugging, when code execution goes to repairsmodel->setFilter("id>76"), I get this error:
-
im not sure what you are doing but just make
refresh_devices_search_tbl a function in
RepairDevicesand you dont need anything else.
RepairDevices::RepairDevices()
{
repairsmodel = new QSqlRelationalTableModel(this); // make it
}void RepairDevices::refresh_devices_search_tbl(){
Ui::RepairDevices *ui; // DONT DO THIS. its evil :)repairsmodel->setFilter("id>76"); // use it
}
-
ok,
then debug it. find where you crash.This also looks a bit odd to me
RepairDevices::RepairDevices()
{
repairsmodel = new QSqlRelationalTableModel(this);
}its that the constructor ?
What about the stuff for QMainWindow ? -
@Panoss
Yes but it jsut says. Programs crashed.
So find your error using the debugger :)If i should guess
i think
RepairDevices::RepairDevices()
{
repairsmodel = new QSqlRelationalTableModel(this);
}is never called and you crash at this line
repairsmodel->setFilter("id>76"); // use it
since repairsmodel is just a dangling pointer. -
@Panoss
Ok fair enough.The errors says that something in the program was fiddling around with some memeory it should not.
so try this and tell me if crash goes away
RepairDevices::RepairDevices() { ////// OUT repairsmodel = new QSqlRelationalTableModel(this); } void refresh_devices_search_tbl(){ // make it here jsut to test repairsmodel = new QSqlRelationalTableModel(this); QString sn = ui->sn_search_txt->toPlainText(); repairsmodel->setFilter("id>76"); qDebug() << "in refresh_devices_search_tbl"; }
also please use
qDebug()
like in sample. it helps alot to see what is called. -
@mrjj said in How to access QSqlRelationalModel from function?:
@Panoss
RepairDevices::RepairDevices()
{
repairsmodel = new QSqlRelationalTableModel(this);
}is never called and you crash at this line
I think you 're right, somehow refresh_devices_search_tbl() is called before repairsmodel = new QSqlRelationalTableModel(this);!!!
I don't understand how is this possible... -
@Panoss said in How to access QSqlRelationalModel from function?:
RepairDevices::RepairDevices()
{
repairsmodel = new QSqlRelationalTableModel(this);
}This looks like the constructor but most likely you are using the one you get from
QMainWindow that takes a parent.
and hence yours is never called.show how you create the RepairDevices instance ?
( i mean where you do like )
RepairDevices *mine= new RepairDevices ( ? ) -
@Panoss said in How to access QSqlRelationalModel from function?:
Hmm i would have expected it to call
your constructor but it seems not. Mainwindow must have one that qualify.Well it seems to use the one u get from your
base class and hence yours is never called.so that is why.
Using a debugger this would be really clear :)
a normal mainwindow constructor looks like this
explicit MainWindow(QWidget *parent = 0); MainWindow::MainWindow(QWidget *parent) : QMainWindow(parent), ui(new Ui::MainWindow) { }
-
@mrjj said in How to access QSqlRelationalModel from function?:
@Panoss said in How to access QSqlRelationalModel from function?:
Hmm i would have expected it to call
your constructor but it seems not.
I thought 'RepairDevices win' calls the constructor.@mrjj said in How to access QSqlRelationalModel from function?:
@Panoss said in How to access QSqlRelationalModel from function?:
Using a debugger this would be really clear :)
I did use the debugger but it was not clear at all to me :).It still isn't, what must I do?
I ''l do mainwindow constructor as you suggested and post the result.I did the test you suggested me above, I had to change a dot to -> (ui->sn_search_txt to ui.sn_search_txt)
repairsmodel = new QSqlRelationalTableModel(this); QString sn = ui.sn_search_txt->toPlainText(); repairsmodel ->setFilter("id>76"); qDebug() << "in refresh_devices_search_tbl";
and got no error.
The etext is not printed, so the refresh_devices_search_tbl is not called now. -
@Panoss said in How to access QSqlRelationalModel from function?:
refresh_devices_search_tbl
who calls it ?
Is it a slot for a button or how should it be called? -
@Panoss
well just check the
connects and its should be clear why its not called.
(connect return true / false)At some point you will also need to learn to use the debugger and set break points.
Its THE BEST tool to find out what is happening and where program goes. :)