设置文本排序及对齐

设置文本排序及对齐

在编写包含格式设置的文本编辑程序时，经常用到的Qt类有：QTextEdit、QTextDocument、QTextCharFormat、QTextCursor、QTextBlock、QTextList、QTextFrame、QTextTable、QTextBlockFormat、QTextListFormat、QTextFrameFormat、QTextTableFormat等。

首先，任何一个文本编辑的程序都要用到QTextEdit作为输入文本的容器，在它里面输入的可编辑文本由QTextDocument作为载体，而QTextDocument的不同表现形式，可能为字符串、段落、列表、表格或是图片等。每种元素都有自己的格式，这些格式则用QTextCharFormat、QTextBlockFormat、QTextListFormat、QTextFrameFormat等类来描述与实现。

1、创建listalign.h

#ifndef LISTALIGN_H
#define LISTALIGN_H

#include <QtGui>

class ListAligh : public QMainWindow
{
    Q_OBJECT
public:
    ListAligh(QWidget *parent = 0);

public slots:
    void slotAlignment(QAction *);
    void slotList(int);
    void slotCursorPositionChanged();

private:
    QTextEdit *text;
    QLabel *label;
    QComboBox *listBox;
    QAction *leftAction;
    QAction *rightAction;
    QAction *centerAction;
    QAction *justifyAction;
    QAction *redoAction;
    QAction *undoAction;
};

#endif // LISTALIGN_H

2、创建listalign.cpp文件

#include "listalign.h"

ListAligh::ListAligh(QWidget *parent) : QMainWindow(parent)
{
    setWindowTitle(tr("List&Alignment"));

    QToolBar *toolBar = addToolBar("list");

    label = new QLabel(tr("List: "));
    listBox = new QComboBox(toolBar);
    listBox->addItem(tr("Standard"));
    listBox->addItem(tr("Bullet List (Disc)"));
    listBox->addItem(tr("Bullet List (Circle)"));
    listBox->addItem(tr("Bullet List (Square)"));
    listBox->addItem(tr("Ordered List (Decimal)"));
    listBox->addItem(tr("Ordered List (Alpha lower)"));
    listBox->addItem(tr("Ordered List (Alpha upper)"));
    toolBar->addWidget(label);
    toolBar->addWidget(listBox);

    toolBar->addSeparator();

    QActionGroup *actGrp = new QActionGroup(this);
    leftAction = new QAction(QIcon(":/images/left.png"),tr("left"),actGrp);
    leftAction->setCheckable(true);

    centerAction = new QAction(QIcon(":/images/center.png"),tr("center"),actGrp);
    centerAction->setCheckable(true);

    justifyAction = new QAction(QIcon(":/images/justify.png"),tr("justify"),actGrp);
    justifyAction->setCheckable(true);

    rightAction = new QAction(QIcon(":/images/right.png"),tr("right"),actGrp);
    rightAction->setCheckable(true);

    toolBar->addActions(actGrp->actions());

    QToolBar *editBar = addToolBar("Edit");
    undoAction = new QAction(QIcon(":/images/undo.png"),tr("undo"),this);
    editBar->addAction(undoAction);
    redoAction = new QAction(QIcon(":/images/redo.png"),tr("redo"),this);
    editBar->addAction(redoAction);

    text =  new QTextEdit(this);
    text->setFocus();
    setCentralWidget(text);

    connect(listBox,SIGNAL(activated(int)),this,SLOT(slotList(int)));
    connect(actGrp,SIGNAL(triggered(QAction*)),this,SLOT(slotAlignment(QAction*)));

    connect(redoAction,SIGNAL(triggered()),text,SLOT(redo()));
    connect(undoAction,SIGNAL(triggered()),text,SLOT(undo()));
    connect(text->document(),SIGNAL(redoAvailable(bool)),redoAction,SLOT(setEnabled(bool)));
    connect(text->document(),SIGNAL(undoAvailable(bool)),undoAction,SLOT(setEnabled(bool)));

    connect(text,SIGNAL(cursorPositionChanged()),this,SLOT(slotCursorPositionChanged()));

}


void ListAligh::slotAlignment(QAction *act)
{
    if (act == leftAction)
        text->setAlignment(Qt::AlignLeft);
    if (act == centerAction)
        text->setAlignment(Qt::AlignCenter);
    if (act == justifyAction)
        text->setAlignment(Qt::AlignJustify);
    if (act == rightAction)
        text->setAlignment(Qt::AlignRight);
}

void ListAligh::slotList(int index)
{
    QTextCursor cursor = text->textCursor();

    if(index != 0)
    {
        QTextListFormat::Style style = QTextListFormat::ListDisc;

        switch(index)
        {
            case 1:
                style = QTextListFormat::ListDisc;
                break;
            case 2:
                style = QTextListFormat::ListCircle;
                break;
            case 3:
                 style = QTextListFormat::ListSquare;
                 break;
             case 4:
                 style = QTextListFormat::ListDecimal;
                 break;
             case 5:
                 style = QTextListFormat::ListLowerAlpha;
                 break;
             case 6:
                 style = QTextListFormat::ListUpperAlpha;
                 break;
             default:
                    break;
        }
        cursor.beginEditBlock();
        QTextBlockFormat blockFmt = cursor.blockFormat();
        QTextListFormat listFmt;
        if(cursor.currentList())
        {
            listFmt = cursor.currentList()->format();
        }
        else
        {
            listFmt.setIndent(blockFmt.indent() + 1);
            blockFmt.setIndent(0);
            cursor.setBlockFormat(blockFmt);
        }

        listFmt.setStyle(style);

        cursor.createList(listFmt);

        cursor.endEditBlock();
    }
}

void ListAligh::slotCursorPositionChanged()
{
    if (text->alignment() == Qt::AlignLeft)
        leftAction->setChecked(true);
    if (text->alignment() == Qt::AlignCenter)
        centerAction->setChecked(true);
    if (text->alignment() == Qt::AlignJustify)
        justifyAction->setChecked(true);
    if (text->alignment() == Qt::AlignRight)
        rightAction->setChecked(true);
}

3、创建main.cpp

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

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

    ListAligh *list = new ListAligh;
    list->show();

    return app.exec();
}

4、创建资源文件，运行

5、资源文件