c++ - Qt:从QAbstractListModel删除多行

Question

有没有一种方法可以有效地从QAbstractListModel中删除不连续的多行？效率低下的例子:

// Single row removal
void remove (int idx) {
    beginRemoveRows (noParent (), idx, idx);
    // internal remove
    endRemoveRows ();
}

// Remove each row by calling beginRemoveRows multiple times
void removeMultiple (const QList<QObject*> &items) {
    foreach (auto item, items)
    {
        int idx = findIndexInternal(item);
        beginRemoveRows (noParent (), idx, idx);
        // internal remove
        endRemoveRows ();
    }
}

问候，

Answer 1

参见Qt's Model-View reference:

This sequence can be used for any structural update in lieu of the more high-level and convenient protected methods. For example, if a model of two million rows needs to have all odd numbered rows removed, that is 1 million discountiguous ranges of 1 element each. It would be possible to use beginRemoveRows and endRemoveRows 1 million times, but that would obviously be inefficient. Instead, this can be signalled as a single layout change which updates all necessary persistent indexes at once.

似乎可以使用 layoutAboutToBeChanged()和 layoutChanged()向基础模型发出较大的更改信号。我还没有测试过。

更新:我目前正在使用这种体系结构，并且可以解决问题。您甚至不必用信号通知行删除/添加，因为这是由布局信号处理的。