QAbstractItemView为截断的项显示ToolTip（使用事件过滤）

在Qt中想要为QAbstractItemView中长度不够而使得内容被截断的项显示ToolTip，Qt官网有一篇文章介绍使用事件过滤器来显示太长的项，但是没有涵盖图标的情况、显示列头项太长的情况等等，这里做了下修改，以符合现在所需。

环境：Qt 5.1.0
atooltipper.h

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18

#ifndef ATOOLTIPPER_H
#define ATOOLTIPPER_H

#include <QObject>

class AToolTipper : public QObject
{
    Q_OBJECT
public:
    explicit AToolTipper(QObject *parent = 0);

    virtual bool eventFilter(QObject *, QEvent *);

protected:
    bool headerViewEventFilter(QObject *, QEvent *);
};

#endif // ATOOLTIPPER_H

atooltipper.cpp

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135

#include "atooltipper.h"
#include <QHelpEvent>
#include <QAbstractItemView>
#include <QHeaderView>
#include <QTreeView>
#include <QTableView>
#include <QToolTip>

AToolTipper::AToolTipper(QObject *parent) :
    QObject(parent)
{
}

bool AToolTipper::eventFilter(QObject *obj, QEvent *event)
{
    if (event->type() == QEvent::ToolTip)
    {
        QAbstractItemView *view = qobject_cast<QAbstractItemView*>(obj->parent());
        if (!view)
        {
            return false;
        }

        QHeaderView *headerView = qobject_cast<QHeaderView*>(view);
        if (headerView)
        {
            return headerViewEventFilter(obj, event);
        }

        QHelpEvent *helpEvent = static_cast<QHelpEvent*>(event);
        QPoint pos = helpEvent->pos();
        QModelIndex index = view->indexAt(pos);
        if (!index.isValid())
        {
            return false;
        }

        QString itemText = view->model()->data(index).toString();

        // 图标处理
        QSize iconSize(0, 0);
        QIcon icon = view->model()->data(index, Qt::DecorationRole).value<QIcon>();
        if (!icon.isNull())
        {
            QList<QSize> listSize = icon.availableSizes();
            if (listSize.size() > 0)
            {
                iconSize.setWidth(listSize.at(0).width());
                iconSize.setHeight(listSize.at(0).height());
            }
        }

        // 计算列头高度
        int headerHeight = 0;
        int headerWidth = 0;
        QTreeView *treeView = qobject_cast<QTreeView*>(view);
        if (treeView)
        {
            headerHeight = treeView->header()->height();
        }
        else
        {
            QTableView *tableView = qobject_cast<QTableView*>(view);
            if (tableView)
            {
                headerHeight = tableView->horizontalHeader()->height();
                headerWidth = tableView->verticalHeader()->width();
            }
        }

        // 文本边距
        const int textMargin = view->style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1;
        const int iconMargin = iconSize.width() > 0 ? (view->style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1) : 0;
        QRect rect = view->visualRect(index);
        QRect textRect = rect.adjusted(textMargin + iconSize.width() + iconMargin * 2, 0, -textMargin, 0); //实际可用矩形

        QFontMetrics fm(view->font());
        int flags = view->model()->data(index, Qt::TextAlignmentRole).toInt();
        QSize itemTextSize = fm.boundingRect(textRect, flags | Qt::TextLongestVariant | Qt::TextWordWrap, itemText).size();

        if ((itemTextSize.width() > textRect.width() || itemTextSize.height() > textRect.height()) && !itemText.isEmpty())
        {
            // 指定tip的限定矩形
            rect.adjust(headerWidth, headerHeight, headerWidth, headerHeight);
            QToolTip::showText(helpEvent->globalPos(), itemText, view, rect);
        }
        else
        {
            QToolTip::hideText();
        }
        return true;
    }

    return false;
}

bool AToolTipper::headerViewEventFilter(QObject *obj, QEvent *event)
{
    if (event->type() == QEvent::ToolTip)
    {
        QHeaderView *headerView = qobject_cast<QHeaderView*>(obj->parent());
        if (!headerView)
        {
            return false;
        }

        QHelpEvent *helpEvent = static_cast<QHelpEvent*>(event);
        QPoint pos = helpEvent->pos();
        int index = headerView->logicalIndexAt(pos);
        if (index < 0)
        {
            return false;
        }

        QString itemText = headerView->model()->headerData(index, headerView->orientation()).toString();
        const int textMargin = headerView->style()->pixelMetric(QStyle::PM_FocusFrameHMargin) + 1;
        int rectWidth = headerView->sectionSize(index) - textMargin * 2;
        int rectHeight = headerView->sizeHint().height();

        QFontMetrics fm(headerView->font());
        int flag = headerView->model()->headerData(index, headerView->orientation(), Qt::TextAlignmentRole).toInt();
        QSize itemTextSize = fm.size(flag, itemText);
        if ((itemTextSize.width() > rectWidth || itemTextSize.height() > rectHeight) && !itemText.isEmpty())
        {
            QToolTip::showText(helpEvent->globalPos(), itemText, headerView);
        }
        else
        {
            QToolTip::hideText();
        }
        return true;
    }

    return false;
}

使用示例：

1
2

tableView->viewport()->installEventFilter(new AToolTipper(tableView));
tableView->horizontalHeader()->viewport()->installEventFilter(new AToolTipper(tableView->horizontalHeader()));

效果图：

参考资料：
1.Show_tooltips_for_long_entries_of_your_custom_model http://qt-project.org/wiki/Show_tooltips_for_long_entries_of_your_custom_model
2.Tooltips for truncated items in a QTreeView http://www.mimec.org/node/337

http://blog.csdn.net/akof1314/article/details/14504747

相关阅读:
POJ
POJ
HDU
HDU
HDU
POJ
HDU
POJ
A-meeting 2019牛客暑期多校第四场（树的直径）
算法与数据结构实验题 2.1 塔防

原文地址：https://www.cnblogs.com/findumars/p/6360867.html