在qt中有这样一个控件：

就是这个Horizontal Slider他的作用相信大家都知道了，也就是通过滑动来改变数值。今天我们就使用这个控件实现一个三原色滑动变色。

实现效果：

1.创建UI界面 

这个就不用多说了，这个大家就按照我的这个去创建就好了。

2.编写代码

首先我们要初始话我们的属性：

  //初始化红色滑动条ui->hsred->setMaximum(255);ui->hsred->setMinimum(0);ui->hsred->setSingleStep(1);ui->hsred->setPageStep(10);ui->hsred->setOrientation(Qt::Horizontal);//初始化绿色ui->hsgreen->setMaximum(255);ui->hsgreen->setMinimum(0);ui->hsgreen->setSingleStep(1);ui->hsgreen->setPageStep(10);ui->hsgreen->setOrientation(Qt::Horizontal);//初始化蓝色ui->hsblue->setMaximum(255);ui->hsblue->setMinimum(0);ui->hsblue->setSingleStep(1);ui->hsblue->setPageStep(10);ui->hsblue->setOrientation(Qt::Horizontal);//设置背景色QString red = QString::number(ui->hsred->value());QString green = QString::number(ui->hsgreen->value());QString blue = QString::number(ui->hsblue->value());ui->lered->setText(red);ui->legreen->setText(green);ui->leblue->setText(blue);QString style = "background-color:rgb("+red+","+green+","+blue+");";ui->lineEdit->setStyleSheet(style);

来讲几个知识点：

//初始化红色滑动条
    ui->hsred->setMaximum(255);//这个 是设置滑动条的上限
    ui->hsred->setMinimum(0);//这个是设置活动条的下限
    ui->hsred->setSingleStep(1);//这个是设置步长
    ui->hsred->setPageStep(10);//这个是你点击的时候滑动条一次增加的量
    ui->hsred->setOrientation(Qt::Horizontal); // 设置滑动条方向为水平 

讲完这个，就开始编写我们的槽函数了

3.槽函数的编写

在ui界面中选中滑动条右键----->转到槽,然后开始敲代码

void Widget::on_hsgreen_valueChanged(int value)
{QString red = QString::number(ui->hsred->value());QString green = QString::number(ui->hsgreen->value());QString blue = QString::number(ui->hsblue->value());ui->legreen->setText(green);QString style = "background-color:rgb("+red+","+green+","+blue+");";ui->lineEdit->setStyleSheet(style);
}

好了，就是如此简单，大家快去试试吧

！！！！！！！！！！！！！！！！！！！！！！！

下课！！！！！！ 

忘了 还有源码：

#include "widget.h"
#include "ui_widget.h"Widget::Widget(QWidget *parent): QWidget(parent), ui(new Ui::Widget)
{ui->setupUi(this);//初始化红色滑动条ui->hsred->setMaximum(255);ui->hsred->setMinimum(0);ui->hsred->setSingleStep(1);ui->hsred->setPageStep(10);ui->hsred->setOrientation(Qt::Horizontal);//初始化绿色ui->hsgreen->setMaximum(255);ui->hsgreen->setMinimum(0);ui->hsgreen->setSingleStep(1);ui->hsgreen->setPageStep(10);ui->hsgreen->setOrientation(Qt::Horizontal);//初始化蓝色ui->hsblue->setMaximum(255);ui->hsblue->setMinimum(0);ui->hsblue->setSingleStep(1);ui->hsblue->setPageStep(10);ui->hsblue->setOrientation(Qt::Horizontal);//设置背景色QString red = QString::number(ui->hsred->value());QString green = QString::number(ui->hsgreen->value());QString blue = QString::number(ui->hsblue->value());ui->lered->setText(red);ui->legreen->setText(green);ui->leblue->setText(blue);QString style = "background-color:rgb("+red+","+green+","+blue+");";ui->lineEdit->setStyleSheet(style);}Widget::~Widget()
{delete ui;
}void Widget::on_hsred_valueChanged(int value)
{QString red = QString::number(ui->hsred->value());QString green = QString::number(ui->hsgreen->value());QString blue = QString::number(ui->hsblue->value());ui->lered->setText(red);QString style = "background-color:rgb("+red+","+green+","+blue+");";ui->lineEdit->setStyleSheet(style);
}void Widget::on_hsgreen_valueChanged(int value)
{QString red = QString::number(ui->hsred->value());QString green = QString::number(ui->hsgreen->value());QString blue = QString::number(ui->hsblue->value());ui->legreen->setText(green);QString style = "background-color:rgb("+red+","+green+","+blue+");";ui->lineEdit->setStyleSheet(style);
}void Widget::on_hsblue_valueChanged(int value)
{QString red = QString::number(ui->hsred->value());QString green = QString::number(ui->hsgreen->value());QString blue = QString::number(ui->hsblue->value());ui->leblue->setText(blue);QString style = "background-color:rgb("+red+","+green+","+blue+");";ui->lineEdit->setStyleSheet(style);
}