Performance problems when parsing large vectors in QML using Repeater - c++

Question

I'm parsing a list of ~4000 emojis from a C++ QAbstractListModel subclass using Repeatables.
The emojis are being collected in a class called EmojiList:
emojilist.h
#include <QVector>
class EmojiList {
public:
struct EmojiData {
EmojiData(const QString& _code, const QString& _shortname, const QString& _category) :
code(_code),
shortname(_shortname),
category(_category)
{}
QString code;
QString shortname;
QString category;
};
static const QVector<EmojiData>& list();
private:
QVector<EmojiData> emojiList;
void parseFromFile();
};
emojilist.cpp
#include "emojilist.h"
#include <QFile>
#include <QTextStream>
const QVector<EmojiList::EmojiData>& EmojiList::list()
{
static EmojiList list;
if (list.emojiList.isEmpty()) {
list.parseFromFile();
}
return list.emojiList;
}
void EmojiList::parseFromFile()
{
QFile emojiResource { ":/media/new_emoji.list" };
if (emojiResource.open(QIODevice::ReadOnly)) {
QTextStream in { &emojiResource };
while (!in.atEnd()) {
QStringList line { in.readLine().split(',') };
emojiList.append({ line.at(0), line.at(1), line.at(2) });
}
}
emojiResource.close();
}
Then, the data is being retrieved in the QAbstractListModel subclass EmojiListModel:
emojilistmodel.cpp
QVariant EmojiListModel::data(const QModelIndex &index, int role) const
{
if (_emojiMap.isEmpty() || !index.isValid() || index.row() > _emojiMap.size()) {
return QVariant();
}
switch (role) {
case EmojiName:
return _emojiMap.at(index.row()).shortname;
case Emoji:
return _emojiMap.at(index.row()).code;
case EmojiCategory: {
return _emojiMap.at(index.row()).category;
}
default:
return QVariant();
}
}
On the front-end side, I'm displaying the model data using a Repeater:
EmojiWindow.qml
ScrollView {
// ...
clip: true
GridLayout {
id: emojiGridView
// ...
Repeater {
id: emojiContainer
model: EmojiListModel {
id: emojiListModel
objectName: "emojiListModel"
}
Rectangle {
// ...
property string delegateEmojiName: emojiName
Text {
id: emojiIcon
text: emoji
// ...
}
MouseArea {
// ...
onClicked: messageField.text += emojiIcon.text
}
}
}
}
}
Now, when starting the application, it takes about 5 minutes to create all Repeater delegates to construct and thus for the whole application to start up.
How can I optimize performance in my QML file to load about 4000 emojis on startup? Is there some way to lazy-load the data to be displayed?
Thanks a lot in advance.