关于QComboBox的currentIndexChanged()信号问题

http://blog.csdn.net/koilin/article/details/7599223

去年开始做界面，不过在过去的一年用的MFC，从今年开始用Qt.确实用Qt来做界面比MFC简单，而且更容易做出来炫炫的效果。折腾的这段时间里，其实每天都会发现新的问题，只是太懒了，一直都没记录下来。今天就来个开始吧：

问题描述：

我有两个QComboBox combo1, combo2：

QComboBox *combo1 = new QComboBox;
QComboBox *combo2 = new QComboBox;
combo1->addItem("1-1");
combo1->addItem("1-2");
combo2->addItem("2-1");
combo2->addItem("2-2");
connect(combo1, SIGNAL(currentIndexChanged(int)), combo2, SLOT(process(int)));
connect(combo2, SIGNAL(currentIndexChanged(int)), combo1, SLOT(process(int)));

	QComboBox *combo1 = new QComboBox;
	QComboBox *combo2 = new QComboBox;
	combo1->addItem("1-1");
	combo1->addItem("1-2");
	combo2->addItem("2-1");
	combo2->addItem("2-2");
	connect(combo1, SIGNAL(currentIndexChanged(int)), combo2, SLOT(process(int)));
	connect(combo2, SIGNAL(currentIndexChanged(int)), combo1, SLOT(process(int)));

然后是信号处理函数：

void process(int index)
{
    QComboBox *combo1 = new QComboBox;
    QComboBox *combo2 = new QComboBox;
    if (sender() == combo1)
    {
        combo2->setCurrentIndex(index);
    }
    else if (sender() == combo2)
    {
        combo1->setCurrentIndex(index);
    }
}

	void process(int index)
	{
		QComboBox *combo1 = new QComboBox;
		QComboBox *combo2 = new QComboBox;
		if (sender() == combo1)
		{
			combo2->setCurrentIndex(index);
		}
		else if (sender() == combo2)
		{
			combo1->setCurrentIndex(index);
		}
	}

这样两个combobox之间就产生了死循环。因为不管是手动改变combobox的当前index还是使用函数来设置当前的index都会发出index改变的消息，此时就需要使用关闭信号：

void process(int index)
{
    QComboBox *combo1 = new QComboBox;
    QComboBox *combo2 = new QComboBox;
    if (sender() == combo1)
    {
        combo2->blockSignals(true);
        combo2->setCurrentIndex(index);
        combo2->blockSignals(false);
    }
    else if (sender() == combo2)
    {
        combo1->blockSignals(true);
        combo1->setCurrentIndex(index);
        combo1->blockSignals(false);
    }
}

	void process(int index)
	{
		QComboBox *combo1 = new QComboBox;
		QComboBox *combo2 = new QComboBox;
		if (sender() == combo1)
		{
			combo2->blockSignals(true);
			combo2->setCurrentIndex(index);
			combo2->blockSignals(false);
		}
		else if (sender() == combo2)
		{
			combo1->blockSignals(true);
			combo1->setCurrentIndex(index);
			combo1->blockSignals(false);
		}
	}

好了，就这么多，写个文章还真不容易啊！