调用show函数却不能显示布局，就像图片上显示一样？为什么

Question

#include <QtGui/QApplication>#include <QMainWindow>#include <QPushButton>#include <QHBoxLayout>#include <QWidget>#include <QCloseEvent>class A:public QMainWindow{public:A();void closeEvent(QCloseEvent *);private:QMainWindow *mainwidow;QWidget *widget;QPushButton *button;QHBoxLayout *layout;};A::A(){mainwidow=new QMainWindow;widget=new QWidget;button=new QPushButton;layout=new QHBoxLayout;layout->addWidget(button);widget->setLayout(layout);mainwidow->setCentralWidget(widget);}void A::closeEvent(QCloseEvent *event){event->ignore();}int main(int argc, char *argv[]){QApplication a(argc, argv);A wm;wm.show();return a.exec();}

Answer 1

A::A(){    //mainwidow=new QMainWindow;    // 本身继承了QMainWindow，没必要再new    widget=new QWidget;    button=new QPushButton;    layout=new QHBoxLayout;    layout->addWidget(button);    widget->setLayout(layout);    //mainwidow->setCentralWidget(widget);    // 把这句改为下面的语句    this->setCentralWidget(widget);}

运行结果如下：（P.S.不知道是你想要的结果吗？）

Answer 2

你是想要画图形么？如果是的话，建议使用QT designer，搭建在VS2010下使用，可以直接画出你想要的图形，在将信号与槽连接就可以了！