python PyQt5对象类型的判定及对象删除操作详细解读

from PyQt5.Qt import *
class Window(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("QObject的学习")
        self.resize(500, 500)
        self.setup_ui()
    def setup_ui(self):
        self.QObject类型判定()
    def QObject类型判定(self):
        # *************API***************开始
        obj = QObject()
        w = QWidget()
        btn = QPushButton()
        label = QLabel()
        objs = [obj, w, btn, label]
        for o in objs:
            print("是否是QWidget的控件类型",o.isWidgetType())
            print("父类是否是QWidget",o.inherits("QWidget"))
            print("父类是否是QPushButton",o.inherits("QPushButton"))
            print("------------------------------------------")
        # *************API***************结束
if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec_())

from PyQt5.Qt import *
class Window(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("QObject的学习")
        self.resize(500, 500)
        self.setup_ui()
    def setup_ui(self):
        self.QObject类型判定()
    def QObject类型判定(self):
        # *************API***************开始
        # obj = QObject()
        # w = QWidget()
        # btn = QPushButton()
        # label = QLabel()
        #
        # objs = [obj, w, btn, label]
        # for o in objs:
        #     print("是否是QWidget的控件类型",o.isWidgetType())
        #     print("父类是否是QWidget",o.inherits("QWidget"))
        #     print("父类是否是QPushButton",o.inherits("QPushButton"))
        #     print("------------------------------------------")
        # *************API***************结束
        # *************案例***************开始
        label1 = QLabel(self)
        label1.setText("景天科技苑")
        label1.move(100, 100)
        label2 = QLabel(self)
        label2.setText("科技不间断")
        label2.move(150, 150)
        btn = QPushButton(self)
        btn.setText("点我")
        btn.move(200, 200)
        #循环遍历子对象
        # for widget in self.findChildren(QLabel):
        for widget in self.children():
            # print(widget)
            # if widget.isWidgetType():
            #将子对象中为QLabel的对象设置背景样式
            if widget.inherits("QLabel"):
                widget.setStyleSheet("background-color: cyan;")
        # *************案例***************结束
if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec_())

from PyQt5.Qt import *
class Window(QWidget):
    def __init__(self):
        super().__init__()
        self.setWindowTitle("QObject的学习")
        self.resize(500, 500)
        self.setup_ui()
    def setup_ui(self):
        self.QObject对象删除()
    def QObject对象删除(self):
        obj1 = QObject()
        #为了防止局部变量运行完方法就销毁，将局部变量赋值给类变量
        self.obj1 = obj1
        obj2 = QObject()
        obj3 = QObject()
        obj3.setParent(obj2)
        obj2.setParent(obj1)
        #创建信号与槽
        obj1.destroyed.connect(lambda : print("obj1被释放了"))
        obj2.destroyed.connect(lambda : print("obj2被释放了"))
        obj3.destroyed.connect(lambda : print("obj3被释放了"))
        #删除对象
        # del obj2  #这样并不能删除
        obj2.deleteLater()
        print(obj1.children())
        #obj2并没有立马被释放
        print("obj2",obj2)
        #执行了deleteLater后，向主消息循环发送了一个event，下一次主消息循环收到这个event之后才会销毁对象，才会真正的去释放相关的对象
if __name__ == '__main__':
    import sys
    app = QApplication(sys.argv)
    window = Window()
    window.show()
    sys.exit(app.exec_())