好吧,我不知道如果我的解決辦法其實是「好」,但它似乎爲我工作:我只是做了從QPlainTextEdit
繼承新類QPlainTextEdit_My
,並增加了新的方法appendPlainTextNoNL()
,appendHtmlNoNL()
,insertNL()
。
請注意:請仔細閱讀關於params check_nl
和check_br
的評論,這很重要!我花了好幾個小時來弄清楚爲什麼我的附件在沒有新段落的情況下追加文本時太慢了。
/******************************************************************************************
* INCLUDED FILES
*****************************************************************************************/
#include "qplaintextedit_my.h"
#include <QScrollBar>
#include <QTextCursor>
#include <QStringList>
#include <QRegExp>
/******************************************************************************************
* CONSTRUCTOR, DESTRUCTOR
*****************************************************************************************/
QPlainTextEdit_My::QPlainTextEdit_My(QWidget *parent) :
QPlainTextEdit(parent)
{
}
QPlainTextEdit_My::QPlainTextEdit_My(const QString &text, QWidget *parent) :
QPlainTextEdit(text, parent)
{
}
/******************************************************************************************
* METHODS
*****************************************************************************************/
/* private */
/* protected */
/* public */
/**
* append html without adding new line (new paragraph)
*
* @param html html text to append
* @param check_nl if true, then text will be splitted by \n char,
* and each substring will be added as separate QTextBlock.
* NOTE: this important: if you set this to false,
* then you should append new blocks manually (say, by calling appendNL())
* because one huge block will significantly slow down your widget.
*/
void QPlainTextEdit_My::appendPlainTextNoNL(const QString &text, bool check_nl)
{
QScrollBar *p_scroll_bar = this->verticalScrollBar();
bool bool_at_bottom = (p_scroll_bar->value() == p_scroll_bar->maximum());
if (!check_nl){
QTextCursor text_cursor = QTextCursor(this->document());
text_cursor.movePosition(QTextCursor::End);
text_cursor.insertText(text);
} else {
QTextCursor text_cursor = QTextCursor(this->document());
text_cursor.beginEditBlock();
text_cursor.movePosition(QTextCursor::End);
QStringList string_list = text.split('\n');
for (int i = 0; i < string_list.size(); i++){
text_cursor.insertText(string_list.at(i));
if ((i + 1) < string_list.size()){
text_cursor.insertBlock();
}
}
text_cursor.endEditBlock();
}
if (bool_at_bottom){
p_scroll_bar->setValue(p_scroll_bar->maximum());
}
}
/**
* append html without adding new line (new paragraph)
*
* @param html html text to append
* @param check_br if true, then text will be splitted by "<br>" tag,
* and each substring will be added as separate QTextBlock.
* NOTE: this important: if you set this to false,
* then you should append new blocks manually (say, by calling appendNL())
* because one huge block will significantly slow down your widget.
*/
void QPlainTextEdit_My::appendHtmlNoNL(const QString &html, bool check_br)
{
QScrollBar *p_scroll_bar = this->verticalScrollBar();
bool bool_at_bottom = (p_scroll_bar->value() == p_scroll_bar->maximum());
if (!check_br){
QTextCursor text_cursor = QTextCursor(this->document());
text_cursor.movePosition(QTextCursor::End);
text_cursor.insertHtml(html);
} else {
QTextCursor text_cursor = QTextCursor(this->document());
text_cursor.beginEditBlock();
text_cursor.movePosition(QTextCursor::End);
QStringList string_list = html.split(QRegExp("\\<br\\s*\\/?\\>", Qt::CaseInsensitive));
for (int i = 0; i < string_list.size(); i++){
text_cursor.insertHtml(string_list.at(i));
if ((i + 1) < string_list.size()){
text_cursor.insertBlock();
}
}
text_cursor.endEditBlock();
}
if (bool_at_bottom){
p_scroll_bar->setValue(p_scroll_bar->maximum());
}
}
/**
* Just insert new QTextBlock to the text.
* (in fact, adds new paragraph)
*/
void QPlainTextEdit_My::insertNL()
{
QScrollBar *p_scroll_bar = this->verticalScrollBar();
bool bool_at_bottom = (p_scroll_bar->value() == p_scroll_bar->maximum());
QTextCursor text_cursor = QTextCursor(this->document());
text_cursor.movePosition(QTextCursor::End);
text_cursor.insertBlock();
if (bool_at_bottom){
p_scroll_bar->setValue(p_scroll_bar->maximum());
}
}
我很困惑,因爲在原來的代碼有很多atBottom
更復雜的計算:
const bool atBottom = q->isVisible()
&& (control->blockBoundingRect(document->lastBlock()).bottom() - verticalOffset()
<= viewport->rect().bottom());
和needScroll
:
if (atBottom) {
const bool needScroll = !centerOnScroll
|| control->blockBoundingRect(document->lastBlock()).bottom() - verticalOffset()
> viewport->rect().bottom();
if (needScroll)
vbar->setValue(vbar->maximum());
}
但是我簡單的解決辦法似乎工作過。
至少Qt的5.2.1 insertPlainText()/ text_cursor.insertText()似乎自動插入塊,當它遇到一個新行。 – iliis