pyQt5-自定义控件

参考：

1、https://maicss.gitbooks.io/pyqt5/content/

2、https://github.com/maicss/PyQt5-Chinese-tutoral

3、https://doc.qt.io/qt-5/classes.html  API

自定义控件

PyQt5有丰富的组件，但是肯定满足不了所有开发者的所有需求，PyQt5只提供了基本的组件，像按钮，文本，滑块等。如果你还需要其他的模块，应该尝试自己去自定义一些。

自定义组件使用绘画工具创建，有两个基本方式：根据已有的创建或改进；通过自己绘图创建。

Burning widget

这个组件我们会在Nero，K3B，或者其他CD/DVD烧录软件中见到。

#!/usr/bin/python3# -*- coding: utf-8 -*-"""ZetCode PyQt5 tutorial In this example, we create a custom widget.本例中，我们使用了QSlider和一个自定义组件，由进度条控制。显示的有物体（也就是CD/DVD）的总容量和剩余容量。进度条的范围是1~750。如果值达到了700（OVER_CAPACITY），就显示为红色，代表了烧毁了的意思。Author: Jan BodnarWebsite: zetcode.com Last edited: August 2017"""from PyQt5.QtWidgets import (QWidget, QSlider, QApplication,    QHBoxLayout, QVBoxLayout)from PyQt5.QtCore import QObject, Qt, pyqtSignalfrom PyQt5.QtGui import QPainter, QFont, QColor, QPenimport sysclass Communicate(QObject):    updateBW = pyqtSignal(int)class BurningWidget(QWidget):    def __init__(self):        super().__init__()        self.initUI()    def initUI(self):        self.setMinimumSize(1, 30)        self.value = 75        self.num = [75, 150, 225, 300, 375, 450, 525, 600, 675]    def setValue(self, value):        self.value = value    def paintEvent(self, e):        qp = QPainter()        qp.begin(self)        self.drawWidget(qp)        qp.end()    def drawWidget(self, qp):        MAX_CAPACITY = 700        OVER_CAPACITY = 750        font = QFont('Serif', 7, QFont.Light)        qp.setFont(font)        size = self.size()        w = size.width()        h = size.height()        step = int(round(w / 10))        till = int(((w / OVER_CAPACITY) * self.value))        full = int(((w / OVER_CAPACITY) * MAX_CAPACITY))        if self.value >= MAX_CAPACITY:            qp.setPen(QColor(255, 255, 255))            qp.setBrush(QColor(255, 255, 184))            qp.drawRect(0, 0, full, h)            qp.setPen(QColor(255, 175, 175))            qp.setBrush(QColor(255, 175, 175))            qp.drawRect(full, 0, till-full, h)        else:            qp.setPen(QColor(255, 255, 255))            qp.setBrush(QColor(255, 255, 184))            qp.drawRect(0, 0, till, h)        pen = QPen(QColor(20, 20, 20), 1,            Qt.SolidLine)        qp.setPen(pen)        qp.setBrush(Qt.NoBrush)        qp.drawRect(0, 0, w-1, h-1)        j = 0        for i in range(step, 10*step, step):            qp.drawLine(i, 0, i, 5)            metrics = qp.fontMetrics()            fw = metrics.width(str(self.num[j]))            qp.drawText(i-fw/2, h/2, str(self.num[j]))            j = j + 1class Example(QWidget):    def __init__(self):        super().__init__()        self.initUI()    def initUI(self):        OVER_CAPACITY = 750        sld = QSlider(Qt.Horizontal, self)        sld.setFocusPolicy(Qt.NoFocus)        sld.setRange(1, OVER_CAPACITY)        sld.setValue(75)        sld.setGeometry(30, 40, 150, 30)        self.c = Communicate()        self.wid = BurningWidget()        self.c.updateBW[int].connect(self.wid.setValue)        sld.valueChanged[int].connect(self.changeValue)        hbox = QHBoxLayout()        hbox.addWidget(self.wid)        vbox = QVBoxLayout()        vbox.addStretch(1)        vbox.addLayout(hbox)        self.setLayout(vbox)        self.setGeometry(300, 300, 390, 210)        self.setWindowTitle('Burning widget')        self.show()    def changeValue(self, value):        self.c.updateBW.emit(value)        self.wid.repaint()if __name__ == '__main__':    app = QApplication(sys.argv)    ex = Example()    sys.exit(app.exec_())