PyQt5：如何单击按钮来移动油漆？

Question

在下面的代码中，单击“Paint”按钮时会生成一个矩形。它还包含一个“移动”按钮。通过单击“移动”按钮，我想在 x 和 y 方向上移动矩形 1px。但我在这里失败了。

我可以理解问题是关于如何在单击按钮时传输变量值。对于初学者来说，这对我来说非常困难。任何帮助将不胜感激！

# -*- coding: utf-8 -*-

from PyQt5.QtWidgets import QWidget, QApplication, QPushButton, QHBoxLayout, QDoubleSpinBox
from PyQt5.QtGui import QPainter, QColor, QBrush
import sys

class Example(QWidget):
    def __init__(self):
        super(Example, self).__init__()
        self.initUI()
        self.flag = False

    def initUI(self):
        self.setFixedSize(400, 400)
        self.setWindowTitle('Colours')
        self.btnPaint = QPushButton("Paint", self)
        self.btnMove = QPushButton("Move x+1 y+1", self)

        self.deltax = 0  # original value
        self.deltay = 0  # original value

        self.btnPaint.clicked.connect(self.onPaint)
        self.btnMove.clicked.connect(self.onMove)


        self.hlayout = QHBoxLayout()
        self.hlayout.addWidget(self.btnPaint)
        self.hlayout.addWidget(self.btnMove)
        self.hlayout.addStretch(1)
        self.setLayout(self.hlayout)


        self.show()

    def onPaint(self):
        self.flag = True
        self.update()

    def onMove(self):
        self.deltax = self.deltax + 1  # button clicked, value +1
        self.deltay = self.deltay + 1  # button clicked, value +1
        self.flag_move = True
        self.update()

    def paintEvent(self, e):
        if self.flag:
            qp = QPainter()
            qp.begin(self)
            self.drawRectangles(qp)
            qp.end()
        if self.flag_move:

            qp = QPainter()
            qp.begin(self)
            self.drawRectangles(qp)
            qp.end()

    def drawRectangles(self, qp):
        x1 = 10
        y1 = 15
        x2 = 90
        y2 = 60

        col = QColor(0, 0, 0)
        col.setNamedColor('#d4d4d4')
        qp.setPen(col)
        qp.setBrush(QColor(200, 0, 0))
        qp.drawRect(x1+self.deltax, y1+self.deltay, x2+self.deltax, y2+self.deltay)



if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

Answer 1

你的代码有错误，因为 self.flag_move 最初没有定义，但也没有必要使用这么多变量。

Qt 有 QRect 类，它有几个方法使任务更容易，最初我们创建一个空 QRect，当按下 btnPaint 按钮时，我们将启用 QRect 到一个非空的。在按下 btnMove 按钮的情况下，我们将使用 translate 方法来移动矩形：

import sys
from PyQt5.QtWidgets import QWidget, QApplication, QPushButton, QHBoxLayout
from PyQt5.QtGui import QPainter, QColor, QBrush
from PyQt5.QtCore import QRect, QPoint

class Example(QWidget):
    def __init__(self):
        super(Example, self).__init__()
        self.initUI()

    def initUI(self):
        self.setFixedSize(400, 400)
        self.setWindowTitle('Colours')
        self.btnPaint = QPushButton("Paint", self)
        self.btnMove = QPushButton("Move x+1 y+1", self)
        self.rect = QRect()

        self.btnPaint.clicked.connect(self.onPaint)
        self.btnMove.clicked.connect(self.onMove)

        self.hlayout = QHBoxLayout(self)
        self.hlayout.addWidget(self.btnPaint)
        self.hlayout.addWidget(self.btnMove)
        self.hlayout.addStretch(1)
        self.show()

    def onPaint(self):
        if self.rect.isNull():
            self.rect = QRect(10, 15, 80, 45)
            self.update()

    def onMove(self):
        if not self.rect.isNull():
            self.rect.translate(QPoint(1, 1))
            self.update()

    def paintEvent(self, e):
        qp = QPainter(self)
        qp.setPen(QColor("#d4d4d4"))
        qp.setBrush(QColor(200, 0, 0))
        qp.drawRect(self.rect)