Qt学习（002-2）

这次是要使得addressbook有添加的功能，记录保存在QMap对象中。
Qt5.1.1下使用creator建立“Gui应用程序”addressbook。

先说一下运行效果：

这是初始界面。

点击add按钮后，add按钮被禁用，隐藏的submit和cancel按钮显示出来，cancel按钮用来清空输入的内容。。我们输入姓名和地址。然后点击Submit按钮：

点击OK后：

Submit和cancel按钮被隐藏，启用add按钮。输入框中仍然保持者我们输入的内容，但是输入框被设置为了只读状态。

建立addressbook.h：

#ifndef ADDRESSBOOK_H
#define ADDRESSBOOK_H

#include <QWidget>
#include <QLineEdit>
#include <QTextEdit>
#include <QPushButton>
#include <QMap>
#include <QString>

class AddressBook : public QWidget
{
    Q_OBJECT

public:
    AddressBook(QWidget *parent = 0);

public slots:
    void addContact();
    void submitContact();
    void cancel();

private:
    QPushButton *addButton;
    QPushButton *submitButton;
    QPushButton *cancelButton;
    QLineEdit *nameLine;
    QTextEdit *addressText;
    QMap<QString, QString> contacts;
    QString oldName;
    QString oldAddress;
};



#endif // ADDRESSBOOK_H

QMap对象contacts用来保存我们的通讯内容。

建立addressbook.cpp：

#include "addressbook.h"

#include <QLabel>
#include <QGridLayout>
#include <QVBoxLayout>
#include <QMessageBox>

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();

    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);
    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();
}

void AddressBook::cancel()
{
    nameLine->setText(oldName);
    nameLine->setReadOnly(true);

    addressText->setText(oldAddress);
    addressText->setReadOnly(true);

    addButton->setEnabled(true);
    submitButton->hide();
    cancelButton->hide();
}

buttonLayout1使用了addStretch()方法，这可以使得其中的部件均匀分布。

更改main.cpp：

#include "addressbook.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    AddressBook addressBook;
    addressBook.show();

    return a.exec();
}

OK。

参考：

http://qt-project.org/doc/qt-4.8/tutorials-addressbook-part2.html