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这段取自http://doc.qt.digia.com/qt/qhboxlayout.html#details的代码片段，除了一些我不知道的魔法之外，充满了潜在的内存泄漏。

编辑：感谢 Nikos C. 指出异常安全在 Qt 中很奇怪，如下所示：http: //doc.qt.digia.com/qt/exceptionsafety.html因此，为了保持我的问题的主要意图有效，我更新了示例代码：

 QWidget *window = new QWidget;
 QPushButton *button1 = new QPushButton("One");
 QPushButton *button2 = new QPushButton("Two");
 QPushButton *button3 = new QPushButton("Three");
 QPushButton *button4 = new QPushButton("Four");
 QPushButton *button5 = new QPushButton("Five");

 QMyWidgetThatCanThrow *myWidget = new QMyWidgetThatCanThrow("");

 QHBoxLayout *layout = new QHBoxLayout;
 layout->addWidget(button1);
 layout->addWidget(button2);
 layout->addWidget(button3);
 layout->addWidget(button4);
 layout->addWidget(button5);
 layout->addWidget(myWidget);

 window->setLayout(layout);
 window->show();

只有在最后才将小部件重新分配给窗口，因此最后两行之前的任何异常都会泄漏所有内容（假设在实际代码中窗口具有父级）。

在类似的非 Qt 代码中，我会使用哨兵对象来处理这种事情。是否有在这里使用哨兵的最佳实践方法，其他人在查看我的代码时会理解？

编辑：这会是可接受的设计模式吗？

void PopulateWindow(QWidget *window)
{
     QWidget sentry;    //serves as the intial parent ensuring that all
                        //widgets are either reparented or deleted
     QPushButton *button1 = new QPushButton("One",&sentry);
     QPushButton *button2 = new QPushButton("Two",&sentry);
     QPushButton *button3 = new QPushButton("Three",&sentry);
     QPushButton *button4 = new QPushButton("Four",&sentry);
     QPushButton *button5 = new QPushButton("Five",&sentry);

     QHBoxLayout *layout = new QHBoxLayout(&sentry);
     layout->addWidget(button1);
     layout->addWidget(button2);
     layout->addWidget(button3);
     layout->addWidget(button4);
     layout->addWidget(button5);

     window->setLayout(layout);
}    //sentry goes out of scope and deletes anything that was not reparented

使用它： 

 QWidget *window = new QWidget;
 PopulateWindow(window);
 window->show();
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1 回答 1

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会出什么问题？你想避免什么问题？如果您创建小部件并且有任何东西迫使您中止，请像在常规 C/C++ 中那样做

if(huhOh!!){
   delete button1;
   delete button2;
   ....
   return false
}

编辑：

没有什么能阻止你做

void PopulateWindow(QWidget *window){

 QPushButton *button1 = new QPushButton("One",window);
 QPushButton *button2 = new QPushButton("Two",window);
 QPushButton *button3 = new QPushButton("Three",window);
 QPushButton *button4 = new QPushButton("Four",window);
 QPushButton *button5 = new QPushButton("Five",window);

 QHBoxLayout *layout = new QHBoxLayout(window);
 layout->addWidget(button1);
 layout->addWidget(button2);
 layout->addWidget(button3);
 layout->addWidget(button4);
 layout->addWidget(button5);

 //layout already set
 //window->setLayout(layout);
}

在这种情况下，您只需删除window

于 2012-12-04T13:41:14.273 回答