Qt setStyleSheet Selector不生效

问题：希望根据控件ID或属性选择不同的样式，当修改了ID或属性后样式并没有改变

官方文档对selector的说明：Selector Types

Property Selector 中提到

Warning: If the value of the Qt property changes after the style sheet has been set, it might be necessary to force a style sheet recomputation. One way to achieve this is to unset the style sheet and set it again.

当属性改变发生在setStyleSheet之后，需要先重新设置一次stylesheet。其实不仅是属性，控件ID也需要做这一步

示例：

测试不同的selector方法

//qtstylesheet.h

#include 
#include "ui_qtstylesheet.h"

class QtStylesheet : public QMainWindow
{
	Q_OBJECT

public:
	QtStylesheet(QWidget *parent = Q_NULLPTR);
	public slots:
	void on_pushButtonObjectName_clicked();
	void on_pushButtonProperty_clicked();
	void on_pushButtonObjectNameProperty_clicked();

private:
	void ActivateStylesheet(QWidget *wig);

	Ui::QtStylesheetClass ui;
};

//qtstylesheet.cpp

#include "qtstylesheet.h"

QtStylesheet::QtStylesheet(QWidget *parent)
	: QMainWindow(parent)
{
	ui.setupUi(this);

	//测试通过ObjectName选择不同的样式
	ui.pushButtonObjectName->setStyleSheet(
		"QPushButton#pushButtonObjectName_1{border:3px solid red; }");

	//测试通过Property选择不同的样式
	ui.pushButtonProperty->setStyleSheet(
		"QPushButton[flag=\"true\"]{border:3px solid green;}");
	ui.pushButtonProperty->setProperty("flag", false);

	//测试通过ObjectName+Property选择不同的样式
	ui.pushButtonObjectNameProperty->setStyleSheet(
		"QPushButton#pushButtonObjectNameProperty[flag=\"true\"]{border:3px solid red;}" \
		"QPushButton#pushButtonObjectNameProperty_1[flag=\"false\"]{border:3px solid yellow;}" \
		"QPushButton#pushButtonObjectNameProperty_1[flag=\"true\"]{border:3px solid green;}" \
		);
	ui.pushButtonObjectNameProperty->setProperty("flag", false);
}

void QtStylesheet::on_pushButtonObjectName_clicked()
{
	static bool flag = true;
	if (flag)
	{
		ui.pushButtonObjectName->setObjectName("pushButtonObjectName_1");  //显示红色边框	 
	}
	else
	{
		ui.pushButtonObjectName->setObjectName("pushButtonObjectName");  //默认样式
	}
	ActivateStylesheet(ui.pushButtonObjectName);  //激活样式
	flag = !flag;
}

void QtStylesheet::on_pushButtonProperty_clicked()
{
	static bool flag = true;
	if (flag)
	{
		ui.pushButtonProperty->setProperty("flag", true);  //显示绿色边框	 
	}
	else
	{
		ui.pushButtonProperty->setProperty("flag", false);  //默认样式
	}
	ActivateStylesheet(ui.pushButtonProperty);  //激活样式
	flag = !flag;
}

void QtStylesheet::on_pushButtonObjectNameProperty_clicked()
{
	static int flag = 1;
	switch (flag)
	{
	case 0:{
			   ui.pushButtonObjectNameProperty->setObjectName("pushButtonObjectNameProperty");
			   ui.pushButtonObjectNameProperty->setProperty("flag", false);
	}break;
	case 1:{
			   ui.pushButtonObjectNameProperty->setObjectName("pushButtonObjectNameProperty");
			   ui.pushButtonObjectNameProperty->setProperty("flag", true);
	}break;
	case 2:{
			   ui.pushButtonObjectNameProperty->setObjectName("pushButtonObjectNameProperty_1");
			   ui.pushButtonObjectNameProperty->setProperty("flag", false);
	}break;
	case 3:{
			   ui.pushButtonObjectNameProperty->setObjectName("pushButtonObjectNameProperty_1");
			   ui.pushButtonObjectNameProperty->setProperty("flag", true);
	}break;
	}
	ActivateStylesheet(ui.pushButtonObjectNameProperty);  //激活样式
	flag++;
	if (flag == 4) flag = 0;
}

void QtStylesheet::ActivateStylesheet(QWidget *wig)
{
	//方案1
	QString ss = wig->styleSheet();
	wig->setStyleSheet("");  //unset
	wig->setStyleSheet(ss);  //set

	//方案2
	//wig->style()->unpolish(wig);
	//wig->style()->polish(wig);
}

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