CODEWITHSUNDEEP
qtqlistview
user2366975
user2366975

Reputation: 4720

QListView wrapping very slow

I want to have a list view just like the one in Windows' file explorer: The data is shown into columns. So I set up a QListView with the code below. It looks totally the same (see picture).

But one major drawback: When resizing the window, the wrapping is very slow. On the contrary, the Window's file browser is very fast.

How can I speed up the wrapping in the QListView?

enter image description here

h:

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    explicit MainWindow(QWidget *parent = 0);
    ~MainWindow();
protected:
    void resizeEvent(QResizeEvent *);
private:
    Ui::MainWindow *ui;
};

cpp:

MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    QStandardItemModel* m=new QStandardItemModel;
    for (int i=100;i<1000;++i){
        m->insertRow(i-100,new QStandardItem(QString::number(i).repeated(5)+"   "));
    }
    ui->listView->setModel(m);
    ui->listView->setWrapping(true);
}

MainWindow::~MainWindow()
{
    delete ui;
}

void MainWindow::resizeEvent(QResizeEvent *e)
{
    QMainWindow::resizeEvent(e);
    ui->listView->setWrapping(ui->listView->isWrapping());
}

Upvotes: 1

Views: 691

Answers (2)

Ani
Ani

Reputation: 42

You don't need to set wrapping every time the widget is resized. Qt is looking for the isWrapping property when resized and decides if a new segment is needed. You just need to set the flow property LeftToRight or TopToBottom and the isWrapping property once when the widget is created. Remove the code from the resizeEvent. Also you can look at the layoutMode property for the performance purposes.

Upvotes: 0

gj13
gj13

Reputation: 1364

I tried your code under Linux with Qt 5.5.1 and wrapping is fast and instant. What Qt version are you using? Qt 4.x has some performance issues under windows.

You can speed things up with NoAntialias

QFont fnt;
fnt.setStyleStrategy(QFont::NoAntialias);
ui->listView->setFont(fnt);

If your list grows bigger and you wan't to insert new data you will get bad performance. You should avoid QStandardItemModel for large sets of data.

Upvotes: 1

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