qt 自定义控件 ：取值范围

自定义 取值范围的控件
如下图所示

功能 : 输入取值范围 $(min,max)$，获取取值范围
WithinRangeEdit.h 文件

#pragma once
#include<QWidget>
#include<QLabel>
#include<QLineEdit>
#include<QHBoxLayout>
class WithinRangeEdit : public QWidget
{
    
	Q_OBJECT
public:
	 WithinRangeEdit(QWidget *parent = nullptr);
	~WithinRangeEdit();
	//获取用户输入的取值范围 ，如果canBeDefaulted=true 则允许缺省
	bool getValue(double &left, double &right, bool canBeDefaulted=true);
	//清空所有输入
	void clear();

private:
	QLabel *m_labelLeft=nullptr ,*m_labelRight = nullptr, *m_labelCernter = nullptr;
	QLineEdit *m_lineEidtLeft = nullptr,*m_lineEidtRight = nullptr;
	QHBoxLayout *m_layout = nullptr;
	//初始化内部控件
	void init();
};

具体实现

#include "WithinRangeEdit.h"
#include<QRegExpValidator>
WithinRangeEdit::WithinRangeEdit(QWidget *parent  ): QWidget(parent)
{
    
	this->init();
}
WithinRangeEdit::~WithinRangeEdit()
{
    

}

void WithinRangeEdit::init()
{
    
	QFont font("Microsoft YaHei", 14);
	 m_labelLeft = new QLabel(" (");
	 m_labelLeft->setFont(font);
	 m_labelRight = new QLabel(") "); 
	 m_labelRight->setFont(font);
	 m_labelCernter = new QLabel(" - ");
	 m_labelCernter->setFont(font);
	 m_lineEidtLeft = new QLineEdit();
	 m_lineEidtLeft->setValidator(new QRegExpValidator(QRegExp("^-?(([0-9]{0,16}(\\.[0-9]{1,8})$)|([0-9]+$))")));//正负整数和浮点数（小数点后限制最多8位）
	 m_lineEidtRight = new QLineEdit();
	 m_lineEidtRight->setValidator(new QRegExpValidator(QRegExp("^-?(([0-9]{0,16}(\\.[0-9]{1,8})$)|([0-9]+$))")));//正负整数和浮点数（小数点后限制最多8位）.
	 m_layout = new QHBoxLayout();
	 m_layout->addWidget(m_labelLeft,1, Qt::AlignHCenter);
	 m_layout->addWidget(m_lineEidtLeft, 1, Qt::AlignHCenter);
	 m_layout->addWidget(m_labelCernter, 1, Qt::AlignHCenter);
	 m_layout->addWidget(m_lineEidtRight, 1, Qt::AlignHCenter);
	 m_layout->addWidget(m_labelRight, 1, Qt::AlignHCenter);
	 m_layout->setContentsMargins(0, 0, 0, 0);
	 m_layout->setStretch(0,0);
	 m_layout->setStretch(1, 1);
	 m_layout->setStretch(2, 0);
	 m_layout->setStretch(3, 1);
	 m_layout->setStretch(4, 0);
	 this->setLayout(m_layout);
}

bool WithinRangeEdit::getValue(double &left, double &right, bool canBeDefaulted)
{
    
	if (m_lineEidtLeft && m_lineEidtRight)
	{
    
		QString strLeft = m_lineEidtLeft->text();
		bool LeftOk;
		left = strLeft.toDouble(&LeftOk);

		QString strRight = m_lineEidtRight->text();
		bool RightOk;
		right = strRight.toDouble(&RightOk);
		
		if (strLeft.isEmpty())
		{
    
			if (canBeDefaulted) //允许缺省：如果最小值为空，则最小值设为无穷小
			{
    
				left = DBL_MIN;
			}
			else
			{
    
				return false;
			}
		}
		else
		{
    
			if (LeftOk)
			{
    
				return false;
			}
		}
		if (strRight.isEmpty())
		{
    
			if (canBeDefaulted) //允许缺省：如果最大值为空，则最小值设为无穷大
			{
    
				right = DBL_MAX;
			}
			else
			{
    
				return false;
			}
		}
		else
		{
    
			if (RightOk)
			{
    
				return false;
			}
		}
	}
	else
	{
    
		return false;
	}
}

void WithinRangeEdit::clear()
{
    
	if (m_lineEidtLeft)
	{
    
		m_lineEidtLeft->clear();
	}
	if (m_lineEidtRight)
	{
    
		m_lineEidtRight->clear();
	}
}

细节：控制数字的输入：

 m_lineEidtLeft->setValidator(new QRegExpValidator(QRegExp("^-?(([0-9]{0,16}(\\.[0-9]{1,8})$)|([0-9]+$))")));

采用正则表达式限制lineEidt的输入：可以输入正负 整数或者浮点数