QSortFilterProxyModel和QTreeView排序功能

1、需求，创建一个树有多层结构，同一层按照插入顺序逆序排列；

ui.treeView->setHeaderHidden(true);     //tree widget头标题是否显示,此处隐藏标题
    //ui.treeWidget->header()->setHorizontalScrollMode(QAbstractItemView::ScrollPerPixel);
    ui.treeView->header()->setSectionResizeMode(QHeaderView::ResizeToContents);
    //ui.treeView->header()->setSectionResizeMode(0, QHeaderView::ResizeToContents);
    ui.treeView->header()->setCascadingSectionResizes(false);
    ui.treeView->header()->setStretchLastSection(true);
    m_modelTree = new QStandardItemModel(ui.treeView);
    m_TreeDelegate = new TreeTaskDelegate(ui.treeView);
    connect(m_TreeDelegate, &TreeTaskDelegate::signalBtClicked, this, &TreeTaskList::SlotTreeBtClicked);
    connect(m_TreeDelegate, &TreeTaskDelegate::signalEditFinish, this, &TreeTaskList::SlotEditFinish);
    ui.treeView->setItemDelegate(m_TreeDelegate);
    m_proxyModel = new QSortFilterProxyModel(ui.treeView);
    m_proxyModel->setSourceModel(m_modelTree);
    ui.treeView->setModel(m_proxyModel);
    m_modelTree->setColumnCount(1);
//    ui.treeView->setSortingEnabled(true);
    //ui.treeView->sortByColumn(0,Qt::AscendingOrder);
    m_proxyModel->setSortRole(Qt::UserRole+1);
    m_proxyModel->sort(0, Qt::DescendingOrder);
    ui.treeView->setIconSize(QSize(24, 24));
    ui.treeView->setColumnWidth(0, 300);

上面设置了一个排序按照角色Qt::UserRole+1去排序，排序方式为逆序排序；插入排序之后可以实现自动排序的功能；创建item的时候把创建时间设置到角色Qt::UserRole+1中去，然后QSortFilterProxyModel就会自动按照这个角色的值进行排序

QStandardItem *topItem = new QStandardItem();
        topItem->setCheckable(true);
        QString path = info.value("path").toString();
        topItem->setData( info.value("createtime").toString(),Qt::UserRole+1);
        info.insert("treeItem", QVariant::fromValue<QStandardItem *>(topItem));
        topItem->setData(info,Qt::UserRole);

如果批量导入，创建时间相同时，没有勾选时排好序，但是点击勾选的时候会出现重新排序，勾选和未勾选的分开排序，勾选的项跑到最下面去了，这不是我想要的排序方式，于是又给时间后面加上了一个rowcount值，在时间相同的情况，rouwcount肯定不一样，所以排序就不会变动

QStandardItem* videoFileItem = new QStandardItem();
    videoFileItem->setCheckable(true);
    //videoFileItem->setText(0, caseInfo.value("createtime").toString());
    QString path = caseInfo.value("path").toString();
    videoTaskInfo.insert("treeItem", QVariant::fromValue<QStandardItem*>(videoFileItem));
    for (auto it = videoTaskInfo.begin(); it != videoTaskInfo.end(); it++)
    {
        caseInfo.insert(it.key(), it.value());
    }
    videoFileItem->setData( caseInfo,Qt::UserRole);
    videoFileItem->setData(caseInfo.value("createtime").toString()+"_"+QString::number(parant->rowCount()), Qt::UserRole+1);//时间相同时，勾选顺序会变动
    videoFileItem->setSizeHint( QSize(300, 40));QSortFilterProxyModel 

方法2

重写QSortFilterProxyModel的lessthan函数，可以实现多个条件或者计算复杂的排序；

bool QTreeTaskFilterProxyModel::lessThan(const QModelIndex &source_left, const QModelIndex &source_right) const
{
    QString left = source_left.data(Qt::UserRole+1).toString();
    QString right = source_right.data(Qt::UserRole).toString();
    return left <= right;
}