起因
QTabWidget默认的tabBar在最上端。
改进
但有时需要将tabBar放置在左侧，但是设置后效果如下…
最终
有时候需要如下效果，则需要自定义style：
附相应代码（具体边框可通过stylesheet进行设置）
1 #include "mainwindow.h"
2 #include "ui_mainwindow.h"
3
4 #include <QPainter>
5 #include <QProxyStyle>
6
7 class CustomTabStyle : public QProxyStyle
8 {
9 public:
10 QSize sizeFromContents(ContentsType type, const QStyleOption *option,
11 const QSize &size, const QWidget *widget) const
12 {
13 QSize s = QProxyStyle::sizeFromContents(type, option, size, widget);
14 if (type == QStyle::CT_TabBarTab) {
15 s.transpose();
16 s.rwidth() = 90; // 设置每个tabBar中item的大小
17 s.rheight() = 44;
18 }
19 return s;
20 }
21
22 void drawControl(ControlElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget) const
23 {
24 if (element == CE_TabBarTabLabel) {
25 if (const QStyleOptionTab *tab = qstyleoption_cast<const QStyleOptionTab *>(option)) {
26 QRect allRect = tab->rect;
27
28 if (tab->state & QStyle::State_Selected) {
29 painter->save();
30 painter->setPen(0x89cfff);
31 painter->setBrush(QBrush(0x89cfff));
32 painter->drawRect(allRect.adjusted(6, 6, -6, -6));
33 painter->restore();
34 }
35 QTextOption option;
36 option.setAlignment(Qt::AlignCenter);
37 if (tab->state & QStyle::State_Selected) {
38 painter->setPen(0xf8fcff);
39 }
40 else {
41 painter->setPen(0x5d5d5d);
42 }
43
44 painter->drawText(allRect, tab->text, option);
45 return;
46 }
47 }
48
49 if (element == CE_TabBarTab) {
50 QProxyStyle::drawControl(element, option, painter, widget);
51 }
52 }
53 };
54
55 MainWindow::MainWindow(QWidget *parent) :
56 QMainWindow(parent),
57 ui(new Ui::MainWindow)
58 {
59 ui->setupUi(this);
60 ui->tabWidget->setTabPosition(QTabWidget::West);
61 ui->tabWidget->tabBar()->setStyle(new CustomTabStyle);
62
63 #if 0
64 ui->tabWidget->setStyleSheet("QTabWidget::pane{ \
65 border-left: 1px solid #eeeeee;\
66 }");
67 #endif
68 }
69
70 MainWindow::~MainWindow()
71 {
72 delete ui;
73 }
