Qt编写自定义控件53-自定义宽高下拉框

#ifndef COMBOBOX_H
#define COMBOBOX_H

/**
 * 自定义宽高下拉框控件 作者:feiyangqingyun(QQ:517216493) 2017-4-11
 * 1:可设置下拉框元素高度
 * 2:可设置下拉框元素宽度
 * 3:可设置是否自动调整下拉框元素宽度,根据元素宽高自动调整
 */

#include <QComboBox>

#ifdef quc
#if (QT_VERSION < QT_VERSION_CHECK(5,7,0))
#include <QtDesigner/QDesignerExportWidget>
#else
#include <QtUiPlugin/QDesignerExportWidget>
#endif

class QDESIGNER_WIDGET_EXPORT ComboBox : public QComboBox
#else
class ComboBox : public QComboBox
#endif

{
    Q_OBJECT
    Q_PROPERTY(int itemWidth READ getItemWidth WRITE setItemWidth)
    Q_PROPERTY(int itemHeight READ getItemHeight WRITE setItemHeight)
    Q_PROPERTY(bool autoWidth READ getAutoWidth WRITE setAutoWidth)

public:
    explicit ComboBox(QWidget *parent = 0);

protected:
    void showEvent(QShowEvent *);

private:
    int itemWidth;                  //元素宽度
    int itemHeight;                 //元素高度
    bool autoWidth;                 //是否自动调整元素宽度
    int maxItemWidth;               //最大元素宽度

public:
    int getItemWidth()              const;
    int getItemHeight()             const;
    bool getAutoWidth()             const;

public Q_SLOTS:
    void setItemWidth(int itemWidth);
    void setItemHeight(int itemHeight);
    void setAutoWidth(bool autoWidth);
};

#endif // COMBOBOX_H

#pragma execution_character_set("utf-8")

#include "combobox.h"
#include "qlistview.h"
#include "qdebug.h"

ComboBox::ComboBox(QWidget *parent) : QComboBox(parent)
{
    itemWidth = 5;
    itemHeight = 20;
    autoWidth = true;
    this->setView(new QListView());
}

void ComboBox::showEvent(QShowEvent *)
{
    if (autoWidth) {
        //自动计算所有元素,找到最长的元素
        QFontMetrics fm = this->fontMetrics();
        int count = this->count();
        for (int i = 0; i < count; i++) {
            int textWidth = fm.width(this->itemText(i));
            itemWidth = textWidth > itemWidth ? textWidth : itemWidth;
        }

        //宽度增加像素,因为有边距
        this->view()->setFixedWidth(itemWidth + 20);
    }
}

int ComboBox::getItemWidth() const
{
    return this->itemWidth;
}

int ComboBox::getItemHeight() const
{
    return this->itemHeight;
}

bool ComboBox::getAutoWidth() const
{
    return this->autoWidth;
}

void ComboBox::setItemWidth(int itemWidth)
{
    if (this->itemWidth != itemWidth) {
        this->itemWidth = itemWidth;
        if (!autoWidth) {
            this->view()->setFixedWidth(itemWidth);
        }
    }
}

void ComboBox::setItemHeight(int itemHeight)
{
    if (this->itemHeight != itemHeight) {
        this->itemHeight = itemHeight;
        this->setStyleSheet(QString("QComboBox QAbstractItemView::item{min-height:%1px;}").arg(itemHeight));
    }
}

void ComboBox::setAutoWidth(bool autoWidth)
{
    if (this->autoWidth != autoWidth) {
        this->autoWidth = autoWidth;
    }
}