Qt中的布局管理器

1. 布局管理器提供相关的类对界面组件进行布局管理，能够自动排列窗口中的界面组件，窗口变化后能自动更新界面组件的大小。

2. QLayout是Qt布局管理器的抽象基类，通过继承QLayout实现了功能各异且互补的布局管理器。

①QBoxLayout: QVBoxLayout, QHBoxLayout

②QGridLayout:

③QFormLayout:

④QStackedLayout:

3. 综合实例（一个简单的安装向导模型）

Widget.h

#ifndef WIDGET_H

#define WIDGET_H

#include <QtGui/QWidget>

#include <QPushButton>

#include <QLabel>

#include <QLineEdit>

class Widget : public QWidget

{

    Q_OBJECT

private:

    QPushButton PreBtn;

    QPushButton NextBtn;

    QLabel Lab0;

    QLabel Lab1;

    QLabel Lab2;

    QLabel Lab3;

    QPushButton PushButton1;

    QPushButton PushButton2;

    QLineEdit LineEdit;

    void InitControl();

    QWidget* GetFirstPage();

    QWidget* GetSecondPage();

    QWidget* GetThirdPage();

private slots:

    void PreBtnClicked();

    void NextBtnClicked();

public:

    Widget(QWidget *parent = );

    ~Widget();

};

#endif // WIDGET_H

Widget.cpp

#include <QVBoxLayout>

#include <QHBoxLayout>

#include <QGridLayout>

#include <QFormLayout>

#include <QStackedLayout>

#include <QDebug>

#include "widget.h"

Widget::Widget(QWidget *parent): QWidget(parent), PreBtn(this), NextBtn(this)

{

    InitControl();

}

void Widget::InitControl()

{

    QVBoxLayout* vLayout = new QVBoxLayout();

    QHBoxLayout* hLayout = new QHBoxLayout();

    QStackedLayout* sLayout = new QStackedLayout();

    PreBtn.setText("Pre Button");

    PreBtn.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

    PreBtn.setMinimumSize(, );

    NextBtn.setText("Next Button");

    NextBtn.setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Fixed);

    NextBtn.setMinimumSize(, );

    sLayout->addWidget(GetFirstPage());

    sLayout->addWidget(GetSecondPage());

    sLayout->addWidget(GetThirdPage());

    hLayout->setSpacing();

    hLayout->addWidget(&PreBtn);

    hLayout->addWidget(&NextBtn);

    vLayout->addLayout(sLayout);

    vLayout->addLayout(hLayout);

    setLayout(vLayout);

    connect(&PreBtn, SIGNAL(clicked()), this, SLOT(PreBtnClicked()));

    connect(&NextBtn, SIGNAL(clicked()), this, SLOT(NextBtnClicked()));

}

QWidget* Widget::GetFirstPage()

{

    QWidget* widget = new QWidget();

    QGridLayout* gLayout = new QGridLayout();

    Lab0.setText("This");

    Lab1.setText("is");

    Lab2.setText("First");

    Lab3.setText("Page");

    gLayout->addWidget(&Lab0, , );

    gLayout->addWidget(&Lab1, , );

    gLayout->addWidget(&Lab2, , );

    gLayout->addWidget(&Lab3, , );

    widget->setLayout(gLayout);

    return widget;

}

QWidget* Widget::GetSecondPage()

{

    QWidget* widget = new QWidget();

    QFormLayout* fLayout = new QFormLayout();

    LineEdit.setText("This is Second Page");

    fLayout->addRow("Name", &LineEdit);

    widget->setLayout(fLayout);

    return widget;

}

QWidget* Widget::GetThirdPage()

{

    QWidget* widget = new QWidget();

    QVBoxLayout* vLayout = new QVBoxLayout();

    PushButton1.setText("Third");

    PushButton2.setText("Page");

    vLayout->addWidget(&PushButton1);

    vLayout->addWidget(&PushButton2);

    widget->setLayout(vLayout);

    return widget;

}

void Widget::PreBtnClicked()

{

    QStackedLayout* sLayout =  dynamic_cast<QStackedLayout*>(((dynamic_cast<QVBoxLayout*>(layout()))->children())[]);

    if(sLayout != NULL)

    {

        int currentIndex = sLayout->currentIndex();

        currentIndex = (currentIndex > ) ? (currentIndex - ) : currentIndex;

        sLayout->setCurrentIndex(currentIndex);

    }

    qDebug() << "PreBtnClicked()";

}

void Widget::NextBtnClicked()

{

    QStackedLayout* sLayout =  dynamic_cast<QStackedLayout*>(((dynamic_cast<QVBoxLayout*>(layout()))->children())[]);

    if(sLayout != NULL)

    {

        int currentIndex = sLayout->currentIndex();

        currentIndex = (currentIndex < ) ? (currentIndex + ) : currentIndex;

        sLayout->setCurrentIndex(currentIndex);

    }

    qDebug() << "NextBtnClicked()";

}

Widget::~Widget()

{

}