QT常规控件操作备忘

QLabel设置边框和颜色：

label->setFrameShape (QFrame::Box);
label->setStyleSheet("border: 1px solid  #ff0000");

 设置字体大小和颜色：

ui.label是QLabel
ui.label_4->setText("some text");
//设置字号
QFont ft;
ft.setPointSize(12);
ui.label_4->setFont(ft);
//设置颜色
QPalette pa;
pa.setColor(QPalette::WindowText,Qt::red);
ui.label_4->setPalette(pa);

QTreeWidget中加入按钮：

void setItemWidget ( QTreeWidgetItem * item, int column, QWidget * widget )；

怎么设置QTreeWidget的列宽？setSizeHint似乎不起作用

QTreeWidgetItem *headItem = watchTree->headerItem();
    headItem->setSizeHint(0,QSize(40,20));
    headItem->setSizeHint(1,QSize(40,20));
    headItem->setText(0,tr("GisRes"));
    headItem->setText(1,tr("period"));

是setLineWidth

为了方便，利用QLabel来形成QSplitter之间的间隙，但是无法精确控制宽度

setSizePolicy(QSizePolicy::Policy horizontal, QSizePolicy::Policy vertical)

遍历树QTreeWidget：

int treeCount(QTreeWidget *tree, QTreeWidgetItem *parent = 0)
{
    int count = 0;
    if (parent == 0) {
        int topCount = tree->topLevelItemCount();
        for (int i = 0; i < topCount; i++) {
            QTreeWidgetItem *item = tree->topLevelItem(i);
            if (item->isExpanded()) {
                count += treeCount(tree, item);
            }
        }
        count += topCount;
    } else {
        int childCount = parent->childCount();
        for (int i = 0; i < childCount; i++) {
            QTreeWidgetItem *item = parent->child(i);
            if (item->isExpanded()) {
                count += treeCount(tree, item);
            }
        }
        count += childCount;
    }
    return count;
}
And the usage:

QTreeWidget tw;
// Add items
[..]
int visibleItemsCount = treeCount(&tw);