简化实现qt中的信号阻塞blockSignals_qt 阻塞信号

作者：秋刀鱼在做梦 | 2024-07-13 00:28:30

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qt 阻塞信号

http://www.oschina.net/code/snippet_54100_1304
QT中经常会用到blockSignals, 且是成对出现，实现时常在函数的开始阻塞信号，在函数的结尾释放信号。
若里面有大量需要阻塞的变量对象，这样写是件很麻烦的事，代码也比较多。
如果能实现象下面的方式实现，这样能简化很多，且不关心释放问题.
下面的例子是关于slider与spinbox联动问题,若改slider影响spinbox,反之如此。

代码片段(2)[全屏查看所有代码]

1. [代码]cpp代码跳至 [1] [2] [全屏预览]

01void  ImEffectWidget::slotSlider(int  pos)
02{
03 static int oldPos = 0;
04 if (oldPos != pos)
05 {
06  QRect r;
07  QObject *o = sender();
08//
09  ImSignalBlock block;
10  block << m_ui.spinBoxTransparent << m_ui.spinBoxVerticalPos
11     << m_ui.spinBoxHerizontalPos << m_ui.spinBoxSTTransparent
12     << m_ui.spinBoxSTVPos;
13  int tabType = m_treeItem->mdata("effect_catalog").toInt();
14  if (tabType == TAB_CATALOG_WATERMARK ){
15   r = m_treeItem->getEffectItem("effect_item_rect").toRect();
16  }
17  
18  /* 3. for watermark  ***************************/
19  else if (o->objectName() == "sliderTransparent"){
20   m_ui.spinBoxTransparent->setValue(pos);  //与spinbox关联
21   m_treeItem->setEffectItem("effect_item_transparent", pos);
22  }else if (o->objectName() == "sliderVerticalPos"){
23   r.moveLeft(pos);
24   m_ui.spinBoxVerticalPos->setValue(pos);
25  }else if (o->objectName() == "sliderHorizontalPos"){
26   r.moveTop(pos);
27   m_ui.spinBoxHerizontalPos->setValue(pos);
28  }
29  /* 5. for subtitle  ***************************/
30  else if (o->objectName() == "sliderSTTransparent"){
31   m_ui.spinBoxSTTransparent->setValue(pos);
32   m_treeItem->setMediaData("effect_subtitle_transparent", pos);
33  }else if (o->objectName() == "sliderSTVPos"){
34   m_ui.spinBoxSTVPos->setValue(pos);
35   m_treeItem->setMediaData("effect_subtitle_pos", pos);
36  }
37  
38  if (tabType == TAB_CATALOG_WATERMARK ){
39   m_treeItem->setEffectItem("effect_item_rect", r);
40  }
41  sendEffectEvent();   //向sdl发信号
42  oldPos = pos;
43 }
44}

2. [代码]ImSignalBlock.h 跳至 [1] [2] [全屏预览]

01#ifndef IMSIGNALBLOCK_H_
02#define IMSIGNALBLOCK_H_
03#include <QObject>
04class  ImSignalBlock
05{
06public:
07 ImSignalBlock();
08 ~ImSignalBlock();
09  ImSignalBlock &operator<< (QObject *o);
10private:
11 QList<QObject*> m_objs;
12};
13#endif
14ImSignalBlock.cpp:
15#include <QDebug>
16#include "ImSignalBlock.h"
17ImSignalBlock::ImSignalBlock()
18{
19}
20ImSignalBlock::~ImSignalBlock()
21{
22 foreach (QObject* o, m_objs)
23 {
24  if (o) o->blockSignals(false);
25 }
26}
27ImSignalBlock &ImSignalBlock::operator<< (QObject *o)
28{
29 if (o)
30 {
31  m_objs.append(o);
32  qDebug() << o->objectName();
33  o->blockSignals(true);
34 }
35 return *this;
36}
 
 
http://blog.csdn.net/koilin/article/details/7599223
 
我有两个QComboBox combo1, combo2：
[cpp] view plaincopyprint?
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：
[cpp] view plaincopyprint?
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：
[cpp] view plaincopyprint?
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);  
    }  
}  
 

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简化实现qt中的信号阻塞blockSignals_qt 阻塞信号

代码片段(2)[全屏查看所有代码]

1. [代码]cpp代码 跳至 [1] [2] [全屏预览]

2. [代码]ImSignalBlock.h 跳至 [1] [2] [全屏预览]

1. [代码]cpp代码跳至 [1] [2] [全屏预览]