PySide/PyQt4繪製節點和連接

Question

試圖創建節點並將它們相互連接。我堆放在setElementPositionAt。錯誤是： AttributeError: 'PySide.QtGui.QPainterPath' object has no attribute 'updateElement' 我在這裏找到了工作代碼：How can I draw nodes and edges in PyQT?但無法將其調整到我的小部件。 我做錯了什麼？ 下面是代碼：

from PySide.QtCore import * 
from PySide.QtGui import * 

rad = 5 


class WindowClass(QMainWindow): 
    def __init__(self): 
     super(WindowClass, self).__init__() 
     self.view = ViewClass() 
     self.setCentralWidget(self.view) 


class ViewClass(QGraphicsView): 
    def __init__(self): 
     super(ViewClass, self).__init__() 

     self.setDragMode(QGraphicsView.RubberBandDrag) 
     self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff) 
     self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff) 

     self.s = SceneClass() 
     self.setScene(self.s) 
     self.setRenderHint(QPainter.Antialiasing) 


class SceneClass(QGraphicsScene): 
    def __init__(self, id=None): 
     super(SceneClass, self).__init__() 
     self.setSceneRect(-1000, -1000, 2000, 2000) 
     self.grid = 30 

     self.p = QPainterPath() 
     self.it = None 
     self.node = None 

    def drawBackground(self, painter, rect): 
     if False: 
      painter = QPainter() 
      rect = QRect() 

     painter.fillRect(rect, QColor(30, 30, 30)) 
     left = int(rect.left()) - int((rect.left()) % self.grid) 
     top = int(rect.top()) - int((rect.top()) % self.grid) 
     right = int(rect.right()) 
     bottom = int(rect.bottom()) 
     lines = [] 
     for x in range(left, right, self.grid): 
      lines.append(QLine(x, top, x, bottom)) 
     for y in range(top, bottom, self.grid): 
      lines.append(QLine(left, y, right, y)) 
     painter.setPen(QPen(QColor(50, 50, 50))) 
     painter.drawLines(lines) 

    def mousePressEvent(self, event): 
     if event.button() == Qt.RightButton: 
      self.p.moveTo(0, 0) 
      self.p.lineTo(200, 100) 
      self.it = Path(self.p,None) 
      self.addItem(self.it) 
      for i in xrange(2): 
       self.node = Node(self, i, QPointF(self.p.elementAt(i))) 
       self.node.setPos(QPointF(self.p.elementAt(i))) 
       self.addItem(self.node) 

     super(SceneClass, self).mousePressEvent(event) 


class Path(QGraphicsPathItem): 
    def __init__(self, path, scene): 
     super(Path, self).__init__(path) 
     self.pth = path 

     self.scn = SceneClass(self.setPen(QPen(Qt.red, 1.75))) 

    def updateElement(self, index, pos): 
     print pos 
     self.pth.setElementPositionAt(index, pos.x(), pos.y()) 
     self.pth.setPath(self) 


class Node(QGraphicsEllipseItem): 
    def __init__(self, path, index, pos): 
     super(Node, self).__init__(-rad, -rad, 2*rad, 2*rad) 

     self.pos = pos 
     self.rad = rad 
     self.path = QPainterPath() 
     self.index = index 
     self.setZValue(1) 
     self.setFlag(QGraphicsItem.ItemIsMovable) 
     self.setFlag(QGraphicsItem.ItemSendsGeometryChanges) 
     self.setBrush(Qt.green) 

    def itemChange(self, change, value): 
     if change == QGraphicsItem.ItemPositionChange: 
      self.path.updateElement(self.index, value) 
     return QGraphicsEllipseItem.itemChange(self, change, value) 

if __name__ == '__main__': 
    app = QApplication([]) 
    wd = WindowClass() 
    wd.show() 
    app.exec_() 

Answer 1

您已經更改到您作爲參考，因此這是正常的，你有錯誤，如果你不理解的代碼基類。

當調用updateElement方法，你必須從Path類的一個實例做，而不是類QPaintePath的一個實例，我已經把你認爲是一項最初參考筆者的相同的代碼和我已經加入到你的圖形部分。

class WindowClass(QMainWindow): 
    def __init__(self): 
     super(WindowClass, self).__init__() 
     self.view = ViewClass() 
     self.setCentralWidget(self.view) 


class ViewClass(QGraphicsView): 
    def __init__(self): 
     super(ViewClass, self).__init__() 

     self.setDragMode(QGraphicsView.RubberBandDrag) 
     self.setHorizontalScrollBarPolicy(Qt.ScrollBarAlwaysOff) 
     self.setVerticalScrollBarPolicy(Qt.ScrollBarAlwaysOff) 

     self.s = SceneClass() 
     self.setScene(self.s) 
     self.setRenderHint(QPainter.Antialiasing) 


class SceneClass(QGraphicsScene): 
    def __init__(self, id=None): 
     super(SceneClass, self).__init__() 
     self.setSceneRect(-1000, -1000, 2000, 2000) 
     self.grid = 30 
     self.it = None 
     self.node = None 

    def drawBackground(self, painter, rect): 
     if False: 
      painter = QPainter() 
      rect = QRect() 

     painter.fillRect(rect, QColor(30, 30, 30)) 
     left = int(rect.left()) - int((rect.left()) % self.grid) 
     top = int(rect.top()) - int((rect.top()) % self.grid) 
     right = int(rect.right()) 
     bottom = int(rect.bottom()) 
     lines = [] 
     for x in range(left, right, self.grid): 
      lines.append(QLine(x, top, x, bottom)) 
     for y in range(top, bottom, self.grid): 
      lines.append(QLine(left, y, right, y)) 
     painter.setPen(QPen(QColor(50, 50, 50))) 
     painter.drawLines(lines) 

    def mousePressEvent(self, event): 
     if event.button() == Qt.RightButton: 
      path = QPainterPath() 
      path.moveTo(0, 0) 
      path.lineTo(200, 100) 
      self.addItem(Path(path, self)) 
     super(SceneClass, self).mousePressEvent(event) 

class Node(QGraphicsEllipseItem): 
    def __init__(self, path, index): 
     super(Node, self).__init__(-rad, -rad, 2*rad, 2*rad) 

     self.rad = rad 
     self.path = path 
     self.index = index 

     self.setZValue(1) 
     self.setFlag(QGraphicsItem.ItemIsMovable) 
     self.setFlag(QGraphicsItem.ItemSendsGeometryChanges) 
     self.setBrush(Qt.green) 

    def itemChange(self, change, value): 
     if change == QGraphicsItem.ItemPositionChange: 
      self.path.updateElement(self.index, value) 
     return QGraphicsEllipseItem.itemChange(self, change, value) 


class Path(QGraphicsPathItem): 
    def __init__(self, path, scene): 
     super(Path, self).__init__(path) 
     for i in range(path.elementCount()): 
      node = Node(self, i) 
      node.setPos(QPointF(path.elementAt(i))) 
      scene.addItem(node) 
     self.setPen(QPen(Qt.red, 1.75))   

    def updateElement(self, index, pos): 
     path = self.path() 
     path.setElementPositionAt(index, pos.x(), pos.y()) 
     self.setPath(path)