QT 软键盘兼容QT4/QT5

前言

软键盘在嵌入式平台开发中被广泛使用
本章代码功能：
1.支持中英双语输入法
2.同时支持QT4/QT5版本
3.支持linux/windows系统

源码地址

https://gitee.com/jiang_bin_yu/softkeyboard

软件功能预览

英文输入法
中文输入法

键盘代码展示

一、设置窗口大小信息

二、加载中文
2.1初始化读取字库表

bool SoftKeyBoard::InitChinese()
{QFile file(":/keyboard/SoftKeyBoard/FontLibrary.txt");int i = 0;if(file.open(QIODevice::ReadOnly)){QString str;QString key;while (true){str = file.readLine();if(str.size() < 4)break;key = str.mid(2,str.size() - 3).replace("\r","");m_map_[key].push_back(str.left(1));++i;}file.close();return true;}return false;
}

2.2 查询中文字库表

void SoftKeyBoard::ShowChinese(QString str,int page,int pos)
{qDebug()<<"ShowChinese"<<str<<page<<pos<<"current"<<m_strPingying_<<m_currentPage_<<m_currentPos_;if(page < 0)page = 0;if(pos < 0 || pos > 11)pos = 0;std::map<QString,std::vector<QString> >::iterator it = m_map_.find(str);ui.lab_pinying_->setText(str);if(it != m_map_.end() && it->second.size() < page * 12)//没有下一页return;for(int i = 0;i < 12;++i){qDebug() << (it != m_map_.end()) << m_map_.size();m_btns_[46 + i]->setText(it != m_map_.end() && it->second.size() > page * 12 + i ? it->second[page * 12 + i] : "");//qDebug()<<"on_btn_language__clicked"<<m_btns_[46 + i]->text()<<i;}if(m_btns_[46 + pos]->text().isEmpty())pos = m_currentPos_;m_strPingying_ = str;m_currentPage_ = page;m_currentPos_ = pos;
}

三、避免QLineEidt焦点丢失
3.1重写QLineEdit

void focusLineEdit::focusInEvent(QFocusEvent *e)
{QLineEdit::focusInEvent(e);this->setFocus();//qDebug() << "focusInEvent";emit focusIn();
}

3.2在键盘中connect绑定光标进入信号

 //设置光标进入 否则进入页面lineEdit 可能无法获取光标connect(ui.wordShow,SIGNAL(focusIn()),this,SLOT(OnfocusIn()));

3.3在键盘中赋予lineEidt光标位置已经焦点

void SoftKeyBoard::OnfocusIn()
{qDebug() << "OnfocusIn";ui.wordShow->setCursorPosition(ui.wordShow->text().size());ui.wordShow->activateWindow();ui.wordShow->setFocus();// this->activateWindow();
}

四、键盘总在窗口底部显示

bool SoftKeyBoard::event(QEvent *e)
{switch (e->type()){case QEvent::WindowActivate:if (m_lastFocusedWidget_)m_lastFocusedWidget_->activateWindow();break;case QEvent::Show:{QDesktopWidget* desktop = QApplication::desktop(); // =qApp->desktop();也可以int centerHeight = (desktop->height() - FatherHeight)/2 + FatherHeight;this->move((desktop->width() - this->width())/2,m_bIsChinese_ ? centerHeight-KeyboardHeightChinese : centerHeight-KeyboardHeightEnglish);break;}default:break;}return QWidget::event(e);
}

五、中英文输入法切换时调整键盘大小以及显示位置

void SoftKeyBoard::on_btn_language__clicked()
{static bool bFirstInit = true;if(m_bIsUppercase_)on_btn_caplock__clicked();m_bIsChinese_ = !m_bIsChinese_;if( bFirstInit && m_bIsChinese_)qDebug()<<"on_btn_language__clicked"<<"open chinese.txt failed.";ui.btn_language_->setText(m_bIsChinese_ ? "中文/英文" : "英文/中文");m_bIsChinese_  ? ui.widget_chinese_->show() : ui.widget_chinese_->hide();//ui.widget_keyboard_->move(0,m_bIsChinese_ ? 100 : 2);resize(KeyboardWidth,m_bIsChinese_ ? KeyboardHeightChinese : KeyboardHeightEnglish);QDesktopWidget* desktop = QApplication::desktop(); // =qApp->desktop();也可以int centerHeight = (desktop->height() - FatherHeight)/2 + FatherHeight;this->move((desktop->width() - this->width())/2,m_bIsChinese_ ? centerHeight-KeyboardHeightChinese : centerHeight-KeyboardHeightEnglish);
}

使用键盘方法

参考文章：QT事件处理–notify()

一、利用notify函数捕获控件按下实际弹出输入框
捕获到按钮事件后判断被按下的对象名如果对象的objectName包含lineEidt则判断需要弹出键盘

bool MyApplication::notify(QObject *receiver, QEvent *e)
{if(e->type() == QEvent::MouseButtonPress)  //receiver->parent() != NULL &&{QMouseEvent *mouseEvent=static_cast<QMouseEvent *>(e);if(receiver != NULL){qDebug() << receiver->objectName();if(receiver->objectName().contains("lineEdit")){if(static_cast<QLineEdit *>(receiver)->isEnabled()){SoftKeyBoard keyBoard;QString text = static_cast<QLineEdit *>(receiver)->text();keyBoard.setValue(text);int key = keyBoard.exec();if(key == QMessageBox::Ok){QString text = keyBoard.getValue();static_cast<QLineEdit *>(receiver)->setText(text);}return QApplication::notify(receiver, e);}}}}return QApplication::notify(receiver, e);
}

二、利用控件槽函数弹出键盘

如QTextEdit控件可以监控selectionChanged信号

void MainWindow::on_textEdit_selectionChanged()
{qDebug() << "on_textEdit_selectionChanged";SoftKeyBoard keyBoard;int key = keyBoard.exec();if(key == QMessageBox::Ok){QString text = keyBoard.getValue();ui->textEdit->append(text);}
}

如Tablewidget控件可以监控itemDoubleClicked信号即双击item时弹出键盘

void MainWindow::on_tableWidget_itemDoubleClicked(QTableWidgetItem *item)
{SoftKeyBoard keyBoard;QString text = item->text();keyBoard.setValue(text);int key = keyBoard.exec();if(key == QMessageBox::Ok){QString text = keyBoard.getValue();item->setText(text);}
}