QComboBox - filtering by typing

michaeldev

Hi!

Does exist working example of app:
QComboBox with filtering items by typing in lineedit
?
Filtering by "contain", not only by first symbols.

Don't propose LineEdit, plz. I'm interested in QComboBox, because I'd like to select item from drop-down list with possibility of filtering.

JonB

@michaeldev
Do you mean: typing into the QComboBox's line edit and having it select corresponding item(s) in the selection list?

EDIT Oh, I see you've edited your question:

Filtering by "contain", not only by first symbols.

I don't know whether there's a better way now, but http://www.qtcentre.org/threads/23143-Combobox-entries-filter-as-I-type [from 2009!] is the same question with a solution using QSortFilterProxyModel .....

michaeldev

@JonB Doesn't work.

SGaist

Hi,

doesn't work is a bit too vague.

mrjj

@michaeldev
Besides, it does work :)
and can use wildcards so its like a contain.
Code directly used from @JonBs link.
However, it can crash when connected directly to TextChanged as filtering and typing interfere and TextChanged triggered while filtering. it seems.
Didnt really debug into it. However, using edit for filter string just works.

alt text )

michaeldev

This post is deleted!

michaeldev

@SGaist said in QComboBox - filtering by typing:

Hi,

doesn't work is a bit too vague.

Did you check that code?

aha_1980

Hi @michaeldev

as you can see two posts above @mrjj tested it for you and it works.

So would you please tell us what's not working for you?

Regards

michaeldev

@aha_1980 said in QComboBox - filtering by typing:

Hi @michaeldev

as you can see two posts above @mrjj tested it for you and it works.

So would you please tell us what's not working for you?

Regards

I wrote "Don't propose LineEdit".

Interesting, filtering works by first symbols (without additional QLineEdit), but doesn't work by "containing".

aha_1980

@michaeldev

don't propose != doesn't work

every combo box includes a line edit, so you can do the filtering within the combo box if you adopt the example.

you cannot expect us to write your code, we just suggest and help. for free! it's up to you to want our help or not.

mrjj

@michaeldev
the lineedit is not important. its just that
the sample would die from recursive calls as we
would filter and type at same time and trigger signal, that trigger filter that trigger signal etc so
i just use lineEdit for input as not to waste time to find out what signal to use instead to fix the sample or why
rapid change of input would make it crash in its own lists. or what ever it was.

it does work fine otherwise finding any combination of wildcards i tried.

I expected you to put a debugger to it and see what is going on. :)

michaeldev

Right now my code :

#ifndef MYCOMBOBOX_H
#define MYCOMBOBOX_H

#include <QComboBox>
#include <QtSql>

class MyComboBox : public QComboBox
{

    Q_OBJECT

public:
    explicit MyComboBox(QWidget *parent);
    virtual void showPopup();
    void focusOutEvent(QFocusEvent* event);
    void init(const QSqlRelationalTableModel *model,
              const int idx,
              const QString &relFiled);

private:
    int relFieldIdx;
};

#endif // MYCOMBOBOX_H

#include "mycombobox.h"

#include <QCompleter>
#include <QApplication>

MyComboBox::MyComboBox(QWidget *parent) :
    QComboBox(parent)
{
}

//Better do this in constructor, but - file ui
void MyComboBox::init(const QSqlRelationalTableModel *model,
                      const int idx,
                      const QString &relFiled)
{
    QSqlTableModel *relModel = model->relationModel(idx);

    relFieldIdx = relModel->fieldIndex(relFiled);

    setModel(relModel);
    setModelColumn(relFieldIdx);
    setEditable(false);
}

void MyComboBox::showPopup()
{
    setEditable(true);

    QCompleter *completer = new QCompleter(model(), this);
    completer->setCompletionMode(QCompleter::PopupCompletion);
    completer->setCompletionColumn(relFieldIdx);
    setCompleter(completer);

    QComboBox::showPopup();
}

void MyComboBox::focusOutEvent(QFocusEvent* event) {

    //This code (probably) should be done differently
    if ((QApplication::focusWidget() != this) && (QApplication::focusWidget() != view()))
        setEditable(false);
    //

    QComboBox::focusOutEvent(event);
}

I don't have filtering by typing "by containing", only "by first symbols". But there is only one widget - MyComboBox. Maybe later I will make filtering in "God's regime ))
Using - first call init(...)

VRonin

Does this do what you want?

#include <QApplication>
#include <QStringListModel>
#include <QPushButton>
#include <QComboBox>
#include <QSortFilterProxyModel>

int main(int argc, char **argv) {
  QApplication app(argc, argv);
  QStringList modleList;
  for(int i=1;i<1000;++i)
  modleList <<  QStringLiteral("%1%2").arg(QLatin1Char('a'+(i%26))).arg(i,3,10,QLatin1Char('0'));
  QStringListModel model(modleList);
  QSortFilterProxyModel filterModel;
  filterModel.setSourceModel(&model);
  QComboBox w;
  w.setModel(&filterModel);
  w.setEditable(true);
  w.setCompleter(nullptr);
  QObject::connect(&w, &QComboBox::editTextChanged, &filterModel, [&filterModel](const QString& input){filterModel.setFilterRegExp('^'+input);},Qt::QueuedConnection);
  w.show();
  app.exec();
  return 0;
}

michaeldev

@VRonin said in QComboBox - filtering by typing:

Does this do what you want?

#include <QApplication>
#include <QStringListModel>
#include <QPushButton>
#include <QComboBox>
#include <QSortFilterProxyModel>

int main(int argc, char **argv) {
  QApplication app(argc, argv);
  QStringList modleList;
  for(int i=1;i<1000;++i)
  modleList <<  QStringLiteral("%1%2").arg(QLatin1Char('a'+(i%26))).arg(i,3,10,QLatin1Char('0'));
  QStringListModel model(modleList);
  QSortFilterProxyModel filterModel;
  filterModel.setSourceModel(&model);
  QComboBox w;
  w.setModel(&filterModel);
  w.setEditable(true);
  w.setCompleter(nullptr);
  QObject::connect(&w, &QComboBox::editTextChanged, &filterModel, [&filterModel](const QString& input){filterModel.setFilterRegExp('^'+input);},Qt::QueuedConnection);
  w.show();
  app.exec();
  return 0;
}

There isn't filtration by content. Am I wrong?

kshegunov

Looking at the code I'm pretty sure there is. Have you actually loaded it in your IDE and given it a try?

michaeldev

@kshegunov said in QComboBox - filtering by typing:

Looking at the code I'm pretty sure there is. Have you actually loaded it in your IDE and given it a try?

Of course.

JonB

@michaeldev said in QComboBox - filtering by typing:

There isn't filtration by content. Am I wrong?

What does the line:

  QObject::connect(&w, &QComboBox::editTextChanged, &filterModel, [&filterModel](const QString& input){filterModel.setFilterRegExp('^'+input);},Qt::QueuedConnection);

do?

michaeldev

@JonB said in QComboBox - filtering by typing:

@michaeldev said in QComboBox - filtering by typing:

There isn't filtration by content. Am I wrong?

What does the line:
  QObject::connect(&w, &QComboBox::editTextChanged, &filterModel, [&filterModel](const QString& input){filterModel.setFilterRegExp('^'+input);},Qt::QueuedConnection);
do?

Have you actually loaded it in your IDE and given it a try?

JonB

@michaeldev
No, I don't have an IDE or a C++ compiler.

kshegunov

@michaeldev said in QComboBox - filtering by typing:

Have you actually loaded it in your IDE and given it a try?

I have and it works. There a couple of GUI tweaks to be done to it, which I imagine are left to you, however the example is functional!