PLC模块的编辑界面

connection.cpp

@@ -1,6 +1,7 @@
 #include "connection.h"
 
 #include <QPen>
+#include <QPainter>
 
 Connection::Connection(Item* from, Item::AnchorType fromType,
                        Item* to, Item::AnchorType toType, QGraphicsItem* parent)
@@ -19,3 +20,14 @@ void Connection::updatePosition()
 {
     setLine(QLineF(from_->anchorPos(fromType_), to_->anchorPos(toType_)));
 }
+
+void Connection::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
+{
+    QPen pen = this->pen();
+    if (isSelected()) {
+        pen.setColor(Qt::red); // 选中变红
+        pen.setWidth(3);
+    }
+    painter->setPen(pen);
+    painter->drawLine(line());
+}

connection.h

@@ -11,6 +11,7 @@ public:
                Item* to, Item::AnchorType toType, QGraphicsItem* parent = nullptr);
 
     void updatePosition();
+    void paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *) override;
 
     Item *from_, *to_;
     Item::AnchorType fromType_, toType_;

item.h

@@ -35,7 +35,6 @@ protected:
 
 private:
     QString type_;
-    QColor  color_;
     QList<Connection*> connections_;
 };
 

mainwindow.cpp

@@ -9,6 +9,7 @@
 #include <QMouseEvent>
 #include <QDropEvent>
 #include <QGraphicsView>
+#include <QMessageBox>
 
 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
@@ -103,3 +104,55 @@ void MainWindow::createComponents()
         it->setData(Qt::UserRole, c.name);
     }
 }
+
+void MainWindow::on_listWidget_currentTextChanged(const QString &text)
+{
+    selectedComponentType = text;
+}
+
+void MainWindow::on_pushButton_clicked()
+{
+    // 1. 找场景中被选中的连线
+       QList<QGraphicsItem*> selectedItems = ui->graphicsView->scene()->selectedItems();
+       Connection* selectedConn = nullptr;
+       for (QGraphicsItem* item : selectedItems) {
+           selectedConn = dynamic_cast<Connection*>(item);
+           if (selectedConn) break;
+       }
+       if (!selectedConn) {
+           QMessageBox::warning(this, "提示", "请先选中一条连线");
+           return;
+       }
+       if (selectedComponentType.isEmpty()) {
+           QMessageBox::warning(this, "提示", "请先在列表中选择要插入的组件");
+           return;
+       }
+
+       // 2. 计算插入点（中点）
+       QLineF lf = selectedConn->line();
+       QPointF insertPos = (lf.p1() + lf.p2()) / 2;
+
+       // 3. 删除原连线
+       Item* from = selectedConn->from_;
+       Item* to = selectedConn->to_;
+       Item::AnchorType fromType = selectedConn->fromType_;
+       Item::AnchorType toType = selectedConn->toType_;
+
+       from->removeConnection(selectedConn);
+       to->removeConnection(selectedConn);
+       ui->graphicsView->scene()->removeItem(selectedConn);
+       delete selectedConn;
+
+       // 4. 插入新元件
+       Item* newItem = new Item(selectedComponentType);
+       newItem->setPos(insertPos);
+       connect(newItem, &Item::requestCopy, ui->graphicsView, &MyGraphicsView::onItemRequestCopy);
+       connect(newItem, &Item::requestDelete, ui->graphicsView, &MyGraphicsView::onItemRequestDelete);
+       ui->graphicsView->scene()->addItem(newItem);
+
+       // 5. 新建两条连线
+       Connection* c1 = new Connection(from, fromType, newItem, Item::Left);
+       ui->graphicsView->scene()->addItem(c1);
+       Connection* c2 = new Connection(newItem, Item::Right, to, toType);
+       ui->graphicsView->scene()->addItem(c2);
+}

mainwindow.h

@@ -19,11 +19,17 @@ public:
 protected:
     bool eventFilter(QObject *obj, QEvent *event) override;
 
+private slots:
+    void on_listWidget_currentTextChanged(const QString &currentText);
+
+    void on_pushButton_clicked();
+
 private:
     void createComponents();
 
     Ui::MainWindow *ui;
     QGraphicsScene *m_scene;
+    QString selectedComponentType;
 };
 
 #endif // MAINWINDOW_H

mainwindow.ui

@@ -37,6 +37,19 @@
      <enum>QGraphicsView::NoDrag</enum>
     </property>
    </widget>
+   <widget class="QPushButton" name="pushButton">
+    <property name="geometry">
+     <rect>
+      <x>30</x>
+      <y>510</y>
+      <width>93</width>
+      <height>28</height>
+     </rect>
+    </property>
+    <property name="text">
+     <string>插入</string>
+    </property>
+   </widget>
   </widget>
   <widget class="QMenuBar" name="menubar">
    <property name="geometry">

mygraphicsview.h

@@ -40,7 +40,7 @@ private:
     };
     static ClipInfo clipboard_;
 
-private slots:
+public slots:
     void onItemRequestCopy(Item*);
     void onItemRequestDelete(Item*);
 };