QPushButton按钮的使用

import sys
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *

class Form(QDialog):
    def __init__(self):
        super(Form, self).__init__()
        layout = QVBoxLayout()

        self.btn1 = QPushButton("Button1")
        self.btn1.setCheckable(True)
        self.btn1.toggle()
        self.btn1.clicked.connect(lambda: self.whichbtn(self.btn1))
        self.btn1.clicked.connect(self.btnstate)
        layout.addWidget(self.btn1)

        self.btn2 = QPushButton("image")
        self.btn2.setIcon(QIcon(QPixmap("chinaz16.png")))
        self.btn2.clicked.connect(lambda : self.whichbtn(self.btn2))
        layout.addWidget(self.btn2)
        self.setLayout(layout)

        self.btn3 = QPushButton("Disabled")
        self.btn3.setEnabled(False)
        layout.addWidget(self.btn3)

        self.btn4 = QPushButton("&Download")
        self.btn4.setDefault(True)
        self.btn4.clicked.connect(lambda: self.whichbtn(self.btn4))
        layout.addWidget(self.btn4)

        self.setWindowTitle("Button demo")

    def btnstate(self):
        if self.btn.isChecked():
            print("button pressed")
        else:
            print("button released")

    def whichbtn(self,btn):
        print("clicked button is "+ btn.text())

if __name__ == '__main__':
    app = QApplication(sys.argv)
    btnDemo = Form()
    btnDemo.show()
    sys.exit(app.exec_())

效果图：