QT Creator 4.7.0 + QT 5.9.6 项目问题记录与解决

问题：对QT中窗口Widget设置背景图片border-image导致窗口的所有控件背景图片都变了。

关键字：背景

思路：在 设计 界面，Widget属性，在 styleSheet 中设置 border-image 并在限制范围。

实作：命名Widget，并限制范围。

范例：Widget名称为Status_monitor

<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="C++" contenteditable="true" cid="n7" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 1em 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">#Status_monitor{border-image: url(:/res/image/background-.bmp);}</pre>

需求：在一个用Qlabel显示的图片上的特定位置显示文字。不使用布局，控件排列与自适应不易；使用布局后，控件如何重叠，

关键字：控件重叠、Widget重叠、GUI控件自适应、控件按比例缩放

思路：方案一：手动排列GUI，用代码实现控件自适应；方案二：解决如何使用布局并控件重叠。

实作：在Widget中加入子Widget，在子Widget中加入Qlabel并于其中布局完成，再手动修改QT UI FILE，将Widget改为Qlabel，最后将其融入整体布局中。

范例：参考CSDN

image

需求：在Qlabel显示的图片上画线。

关键字：在label控件上画线、控件 画线、控件 画图、在任意控件上画图

思路：继承一个QLabel，然后在paintEvent中画。

实作：参考CSDN

1. 用向导生成一个新类比如LineLabel，继承于QLabel。

2. 添加虚函数 virtual void paintEvent(QPaintEvent *) override 在其中编写绘画内容

3. 在 设计界面 ，找到作为底图的QLabel，在 对象查看 中 右键点击类名称，选择提升，里面填LineLabel，保存，重新生成。

linelabel.h

<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="C++" contenteditable="true" cid="n29" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 1em 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">#ifndef LINELABEL_H

define LINELABEL_H

include <QLabel>

include <QPoint>

include <QColor>

include <QPaintEvent>

​
class LineLabel : public QLabel
{
public:
LineLabel(QWidget *parent = nullptr);
​
//绘制线条
virtual void paintEvent(QPaintEvent *event) override;
//得到画线的起点和终点
void getStartPoint(QPoint SPoint);
void getEndPoint(QPoint EPoint);
​
private:
QPoint lineStartPoint; //画线起点
QPoint lineEndPoint; //画线终点
QColor lineColor; //线条颜色
int lineSize;
};
​

endif // LINELABEL_H</pre>

linelabel.cpp

<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="C++" contenteditable="true" cid="n32" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 1em 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">#include "linelabel.h"

include <QPen>

include <QPainter>

​
//初始化
LineLabel::LineLabel(QWidget *parent):QLabel(parent)
{
this->lineStartPoint = QPoint(0,0);
this->lineEndPoint = QPoint(0,0);
this->lineColor = QColor(Qt::red);
this->lineSize = 3;
}
​
//绘制线条
void LineLabel::paintEvent(QPaintEvent *event)
{
QLabel::paintEvent(event);
QPainter painter(this);
QPen pen;
pen.setColor(lineColor);
pen.setWidth(lineSize);
painter.setPen(pen);
painter.drawLine(lineStartPoint,lineEndPoint);
}
​
void getStartPoint(QPoint SPoint)
{
lineStartPoint = SPoint；
}
​
void getEndPoint(QPoint EPoint)
{
lineEndPoint = EPoint;
}
​</pre>

status_monitor.cpp

<pre spellcheck="false" class="md-fences md-end-block ty-contain-cm modeLoaded" lang="C++" contenteditable="true" cid="n35" mdtype="fences" style="box-sizing: border-box; overflow: visible; font-family: var(--monospace); font-size: 0.9em; display: block; break-inside: avoid; text-align: left; white-space: normal; background-image: inherit; background-position: inherit; background-size: inherit; background-repeat: inherit; background-attachment: inherit; background-origin: inherit; background-clip: inherit; background-color: rgb(248, 248, 248); position: relative !important; border: 1px solid rgb(231, 234, 237); border-radius: 3px; padding: 8px 1em 6px; margin-bottom: 15px; margin-top: 15px; width: inherit; color: rgb(51, 51, 51); font-style: normal; font-variant-ligatures: normal; font-variant-caps: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-indent: 0px; text-transform: none; widows: 2; word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration-style: initial; text-decoration-color: initial;">#include "status_monitor.h"

include "ui_status_monitor.h"

​
Status_monitor::Status_monitor(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::Status_monitor)
{
ui->setupUi(this);
QTimer *timer = new QTimer(this);
connect(timer,SIGNAL(timeout()),this,SLOT(timerUpdate()));
timer->start(1000);
}
​
Status_monitor::~Status_monitor()
{
delete ui;
}
​
​
void Status_monitor::timerUpdate(void)
{
int x1, x2, y1, y2;
x1 = 0;
y1 = 0;
x2 = 100;
y2 = 100;
ui->lbTIME->getStartPoint(x1,y1);
ui->lbTIME->getEndPoint(x2,y2);
ui->lbTIME->update();
}</pre>

使用windeployqt打包封装后遇到数据库连接异常

关键字：打包、封装、数据库

思路：缺啥补啥。

实作：把 libmysql.lib 和 libmysql.dll 复制到exe同级目录下。

另外打包封装参考CSDN。