此次是添加查看条目功能。 Qt5.1.1下用creator建立项目addressbook。

创建addressbook.h：

#ifndef ADDRESSBOOK_H#define ADDRESSBOOK_H#include 
    
     #include 
     
      #include 
      
       #include 
       
        #include 
        
         #include 
         
          class AddressBook : public QWidget{ Q_OBJECTpublic: AddressBook(QWidget *parent = 0);public slots: void addContact(); void submitContact(); void cancel(); void next(); void previous();private: QPushButton *addButton; QPushButton *submitButton; QPushButton *cancelButton; QPushButton *nextButton; QPushButton *previousButton; QLineEdit *nameLine; QTextEdit *addressText; QMap
          
            contacts; QString oldName; QString oldAddress;};#endif // ADDRESSBOOK_H
          
         
        
       
      
     
    

可以看到新增了两个按钮：nextButton和previousButton；新增了两个槽next()、previous()。

新建addressbook.cpp：

#include "addressbook.h"#include 
    
     #include 
     
      #include 
      
       #include 
       
        #include 
        
         AddressBook::AddressBook(QWidget *parent)    : QWidget(parent){    QLabel *nameLabel = new QLabel(tr("Name:"));    nameLine = new QLineEdit;    nameLine->setReadOnly(true);    QLabel *addressLabel = new QLabel(tr("Address:"));    addressText = new QTextEdit;    addressText->setReadOnly(true);    addButton = new QPushButton(tr("&Add"));    addButton->show();    submitButton = new QPushButton(tr("&Submit"));    submitButton->hide();    cancelButton = new QPushButton(tr("&Cancel"));    cancelButton->hide();    connect(addButton, SIGNAL(clicked()), this, SLOT(addContact()));    connect(submitButton, SIGNAL(clicked()), this, SLOT(submitContact()));    connect(cancelButton, SIGNAL(clicked()), this, SLOT(cancel()));    QVBoxLayout *buttonLayout1 = new QVBoxLayout;    buttonLayout1->addWidget(addButton, Qt::AlignTop);    buttonLayout1->addWidget(submitButton);    buttonLayout1->addWidget(cancelButton);    buttonLayout1->addStretch();    nextButton = new QPushButton(tr("&Next"));    nextButton->setEnabled(false);    previousButton = new QPushButton(tr("&Previous"));    previousButton->setEnabled(false);    connect(nextButton, SIGNAL(clicked()), this, SLOT(next()));    connect(previousButton, SIGNAL(clicked()), this, SLOT(previous()));    QHBoxLayout *buttonLayout2 = new QHBoxLayout;    buttonLayout2->addWidget(previousButton);    buttonLayout2->addWidget(nextButton);    QGridLayout *mainLayout = new QGridLayout;    mainLayout->addWidget(nameLabel, 0, 0);    mainLayout->addWidget(nameLine, 0, 1);    mainLayout->addWidget(addressLabel, 1, 0, Qt::AlignTop);    mainLayout->addWidget(addressText, 1, 1);    mainLayout->addLayout(buttonLayout1, 1, 2);    mainLayout->addLayout(buttonLayout2, 2, 1);    setLayout(mainLayout);    setWindowTitle(tr("Simple Address Book"));}void AddressBook::addContact(){    oldName = nameLine->text();    oldAddress = addressText->toPlainText();    nameLine->clear();    addressText->clear();    nameLine->setReadOnly(false);    nameLine->setFocus(Qt::OtherFocusReason);    addressText->setReadOnly(false);    addButton->setEnabled(false);    submitButton->show();    cancelButton->show();}void AddressBook::submitContact(){    QString name = nameLine->text();    QString address = addressText->toPlainText();    if (name.isEmpty() || address.isEmpty()) {        QMessageBox::information(this, tr("Empty Field"),            tr("Please enter a name and address."));        return;    }    if (!contacts.contains(name)) {        contacts.insert(name, address);        QMessageBox::information(this, tr("Add Successful"),            tr("\"%1\" has been added to your address book.").arg(name));    } else {        QMessageBox::information(this, tr("Add Unsuccessful"),            tr("Sorry, \"%1\" is already in your address book.").arg(name));        return;    }    if (contacts.isEmpty()) {        nameLine->clear();        addressText->clear();    }    nameLine->setReadOnly(true);    addressText->setReadOnly(true);    addButton->setEnabled(true);    submitButton->hide();    cancelButton->hide();    int number = contacts.size();    nextButton->setEnabled(number > 1);    previousButton->setEnabled(number > 1);}void AddressBook::cancel(){    nameLine->setText(oldName);    nameLine->setReadOnly(true);    addressText->setText(oldAddress);    addressText->setReadOnly(true);    addButton->setEnabled(true);    submitButton->hide();    cancelButton->hide();}void AddressBook::next(){    QString name = nameLine->text();    QMap
         
          ::iterator i = contacts.find(name); if (i != contacts.end()) i++; if (i == contacts.end()) i = contacts.begin(); nameLine->setText(i.key()); addressText->setText(i.value());}void AddressBook::previous(){ QString name = nameLine->text(); QMap
          
           ::iterator i = contacts.find(name); if (i == contacts.end()){ nameLine->clear(); addressText->clear(); return; } if (i == contacts.begin()) i = contacts.end(); i--; nameLine->setText(i.key()); addressText->setText(i.value());}
          
         
        
       
      
     
    

在构造函数中可以看到新建了水平布局buttonLayout2，并将nextButton和previousButton添加到该布局中。buttonLayout2布局被添加到mainLayout布局中。 next()和previous()方法中主要是对QMap对象的操作。  contacts对象的find()方法会返回一个STL风格的迭代器，该迭代器是key等于find()参数的第一个键值对。 关于QMap，详细见： 。 开始时候，next和previous按钮是禁用状态，但是在submitContact()中的：

int number = contacts.size();    nextButton->setEnabled(number > 1);    previousButton->setEnabled(number > 1);

当添加的条目大于1时候，这两个按钮被激活。

修改main.cpp：

#include "addressbook.h"#include 
    
     int main(int argc, char *argv[]){    QApplication a(argc, argv);    AddressBook addressBook;    addressBook.show();    return a.exec();}
    

运行结果：

#include "addressbook.h"#include 
    
     int main(int argc, char *argv[]){    QApplication a(argc, argv);    AddressBook addressBook;    addressBook.show();    return a.exec();}
    

参考：

http://qt-project.org/doc/qt-4.8/tutorials-addressbook-part3.html