QPlainEdit编辑功能

Public Slots

void appendHtml ( const QString & html )void appendPlainText ( const QString & text )void centerCursor ()void clear ()void copy ()void cut ()void insertPlainText ( const QString & text )void paste ()void redo ()void selectAll ()void setPlainText ( const QString & text )void undo ()

Signals

void blockCountChanged ( int newBlockCount );//每当按下回车或者删除回车(更新字符块),则newBlockCount计数,并触发该信号, newBlockCount 默认为1void copyAvailable ( bool yes );//选择某串文字时,则触发该信号,并设置yes为true,如果取消选择,也会触发该信号,设置 yes为falsevoid cursorPositionChanged ()////每当光标的位置发生变化时，触发该信号void redoAvailable ( bool available );//当文本框为空,则会触发该信号,并设置available为false,因为该文本框没有数据,所以无法重做//当用户向空文本框输入数据时,同样也会触发该信号,设置available为true,表示可以实现重做void selectionChanged ();//当鼠标点击文本框时,触发该信号void textChanged ();//每当文档的内容发生变化时,则触发该信号,可以用来判断输入的字符是什么 void undoAvailable ( bool available );//当用户无法撤销时,便会触发该信号,并设置available为false//当用户修改/写入文本框内容,便会触发该信号,并设置available为true,表示可以撤销

 

 

示例代码

Widget.h:

#ifndef WIDGET_H#define WIDGET_H#include 
     
      #include 
      
       #include 
       
        #include 
        
         class Widget : public QWidget{    Q_OBJECT    QPlainTextEdit edit;    QPushButton* Undo;    QPushButton*  Redo;    QPushButton* Cut;    QPushButton* Copy;    QPushButton* Paste;    QPushButton* all;    QPushButton* clear;private slots:    void       oncopyAvailable ( bool yes );    void       onredoAvailable ( bool available );    void       onundoAvailable ( bool available );public:    explicit Widget(QWidget *parent = 0);};#endif
        
       
      
     

 

Widget.c:

#include "Widget.h"Widget::Widget(QWidget *parent) :    QWidget(parent),    edit(this){    edit.setGeometry(0,0,280,300);    Undo= new QPushButton("重做",this);    Redo= new QPushButton("撤销",this);    Cut= new QPushButton("剪切",this);    Copy= new QPushButton("复制",this);    Paste= new QPushButton("拷贝",this);    all=  new QPushButton("全选",this);    clear=  new QPushButton("删除",this);    Undo->setGeometry(290,0,100,30);    Redo->setGeometry(290,40,100,30);    Cut->setGeometry(290,80,100,30);    Copy->setGeometry(290,120,100,30);    Paste->setGeometry(290,160,100,30);    all->setGeometry(290,200,100,30);    clear->setGeometry(290,240,100,30);    Undo->setEnabled(false);    Redo->setEnabled(false);    Cut->setEnabled(false);    Copy->setEnabled(false);    /*设置按键与文本框槽的关系*/    connect(Undo, SIGNAL(clicked()) , &edit ,SLOT(undo()));    connect(Redo, SIGNAL(clicked()) ,  &edit ,SLOT(redo()));    connect(Cut, SIGNAL(clicked()) ,    &edit ,SLOT(cut()));    connect(Copy, SIGNAL(clicked()) ,    &edit ,SLOT(copy()));    connect(Paste, SIGNAL(clicked()) ,    &edit ,SLOT(paste()));    connect(all, SIGNAL(clicked()) ,  &edit ,SLOT(selectAll()));    connect(clear, SIGNAL(clicked()) ,  &edit ,SLOT(clear()));    /*设置文本框信号与槽函数的关系*/    connect(&edit, SIGNAL(copyAvailable(bool)) , this ,SLOT(oncopyAvailable(bool)));    connect(&edit, SIGNAL(redoAvailable(bool)) , this ,SLOT(onredoAvailable(bool)));    connect(&edit, SIGNAL(undoAvailable(bool)) , this ,SLOT(onundoAvailable(bool)));    connect(&edit, SIGNAL(selectionChanged()) , this ,SLOT(onselectionChanged()));}void    Widget::oncopyAvailable ( bool yes ){       Cut->setEnabled(yes);       Copy->setEnabled(yes);}void    Widget::onredoAvailable( bool available ){       Redo->setEnabled(available);}void    Widget::onundoAvailable ( bool available ){       Undo->setEnabled(available);}

效果: