Qt实战开发-数字软键盘

开发的思路

布局键盘界面

每一个button对应一个槽函数

把输入的字符返回到点击处的文本编辑框

开发过程

首先定义功能button，在头文件中定义

QString getText();
QPushButton *num6Button;
QPushButton *backspaceButton;
QPushButton *num4Button;
QPushButton *okButton;
QPushButton *leftButton;
QPushButton *num1Button;
QPushButton *cancelButton;
QPushButton *rightButton;
QPushButton *num9Button;
QPushButton *num8Button;
QPushButton *num2Button;
QPushButton *num7Button;
QPushButton *dotButton;
QPushButton *num3Button;
QPushButton *num0Button;
QPushButton *num5Button;
QPushButton *signButton;
QLineEdit *lineEdit;

接着定义相关联的槽函数

void on_num1Button_clicked();
void on_num2Button_clicked();
void on_num3Button_clicked();
void on_num4Button_clicked();
void on_num5Button_clicked();
void on_num6Button_clicked();
void on_num7Button_clicked();
void on_num8Button_clicked();
void on_num9Button_clicked();
void on_dotButton_clicked();
void on_num0Button_clicked();
void on_signButton_clicked();
void on_leftButton_clicked();
void on_rightButton_clicked();
void on_backspaceButton_clicked();
void on_cancelButton_clicked();
void on_okButton_clicked();

下面定义界面布局显示的功能模块

okButton = new QPushButton(this);
okButton->setText(" OK");
okButton->setGeometry(QRect(190, 250, 110, 50));
QFont font1;
font1.setPointSize(14);
okButton->setFont(font1);

backspaceButton = new QPushButton(this);
backspaceButton->setText(" backspace");
backspaceButton->setGeometry(QRect(190, 130, 110, 50));
backspaceButton->setFont(font1);

num6Button = new QPushButton(this);
num6Button->setText("6");
num6Button->setGeometry(QRect(130, 130, 50, 50));
QFont font;
font.setPointSize(22);
num6Button->setFont(font);

num4Button = new QPushButton(this);
num4Button->setText(" 4");
num4Button->setGeometry(QRect(10, 130, 50, 50));
num4Button->setFont(font);

leftButton = new QPushButton(this);
leftButton->setText("<-");
leftButton->setGeometry(QRect(190, 190, 50, 50));
leftButton->setFont(font);

num1Button = new QPushButton(this);
num1Button->setText("1");
num1Button->setGeometry(QRect(10, 70, 50, 50));
num1Button->setFont(font);

cancelButton = new QPushButton(this);
cancelButton->setText("Esc");
cancelButton->setGeometry(QRect(190, 70, 110, 50));
cancelButton->setFont(font1);

rightButton = new QPushButton(this);
rightButton->setText("->");
rightButton->setGeometry(QRect(250, 190, 50, 50));
rightButton->setFont(font);

num9Button = new QPushButton(this);
num9Button->setText("9");
num9Button->setGeometry(QRect(130, 190, 50, 50));
num9Button->setFont(font);

num8Button = new QPushButton(this);
num8Button->setText("8");
num8Button->setGeometry(QRect(70, 190, 50, 50));
num8Button->setFont(font);

num2Button = new QPushButton(this);
num2Button->setText("2");
num2Button->setGeometry(QRect(70, 70, 50, 50));
num2Button->setFont(font);

num7Button = new QPushButton(this);
num7Button->setText("7");
num7Button->setGeometry(QRect(10, 190, 50, 50));
num7Button->setFont(font);

dotButton = new QPushButton(this);
dotButton->setText(".");
dotButton->setGeometry(QRect(130, 250, 50, 50));
dotButton->setFont(font);

num3Button = new QPushButton(this);
num3Button->setText("3");
num3Button->setGeometry(QRect(130, 70, 50, 50));
num3Button->setFont(font);

num0Button = new QPushButton(this);
num0Button->setText("0");
num0Button->setGeometry(QRect(10, 250, 50, 50));
num0Button->setFont(font);

num5Button = new QPushButton(this);
num5Button->setText("5");
num5Button->setGeometry(QRect(70, 130, 50, 50));
num5Button->setFont(font);

signButton = new QPushButton(this);
signButton->setText("+/-");
signButton->setGeometry(QRect(70, 250, 50, 50));
QFont font2;
font2.setPointSize(20);
signButton->setFont(font2);

lineEdit = new QLineEdit(this);
lineEdit->setGeometry(QRect(10, 10, 290, 50));
QFont font3;
font3.setPointSize(24);
font3.setWeight(50);
lineEdit->setFont(font3);
lineEdit->setText(QString());

相应的槽函数功能

void NumKeyboard::changeEvent(QEvent *e)
{
QDialog::changeEvent(e);
switch (e->type()) {
case QEvent::LanguageChange:
break;
default:
break;
}
}

bool NumKeyboard::eventFilter(QObject *obj, QEvent *event)
{
if (event->type() == QEvent::KeyPress)
{
QKeyEvent *keyEvent = static_cast<QKeyEvent *>(event);
if (obj == lineEdit)
{
if(keyEvent->key() >= 0x20 && keyEvent->key()<= 0x0ff)
return true;
else
return false;
}
else
{
return false;
}
}
else
{
// standard event processing
return QObject::eventFilter(obj, event);
}
}

//***********************按键*****************************//
void NumKeyboard::on_num1Button_clicked()       //1
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}

strContent.insert(idx, '1');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
qDebug()<<"strContent"<<strContent;
qDebug()<<"idx"<<idx;
}

void NumKeyboard::on_num2Button_clicked()       //2
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '2');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_num3Button_clicked()       //3
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '3');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_num4Button_clicked()       //4
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '4');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_num5Button_clicked()       //5
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '5');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_num6Button_clicked()       //6
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '6');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_num7Button_clicked()       //7
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '7');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_num8Button_clicked()       //8
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '8');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_num9Button_clicked()       //9
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '9');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_dotButton_clicked()        //.
{
int idx = lineEdit->cursorPosition();

if(idx==0 || strContent.contains('.'))
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}

strContent.insert(idx, '.');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_num0Button_clicked()       //0
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0" || (idx==0 &&strContent!=""))
{
lineEdit->setCursorPosition(idx);
qDebug()<<"idx"<<idx;
lineEdit->setFocus();
return;
}
strContent.insert(idx, '0');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_signButton_clicked()       //+/-
{
int idx = lineEdit->cursorPosition();
if(strContent.left(1) == "-")
{
strContent.remove(0, 1);
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx-1);
lineEdit->setFocus();
}
else
{
if(strContent=="0" || strContent=="")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
}
else
{
strContent.insert(0, '-');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}
}
}

void NumKeyboard::on_leftButton_clicked()       //left
{
int idx = lineEdit->cursorPosition();
if(idx == 0)
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
lineEdit->setCursorPosition(idx-1);
lineEdit->setFocus();
}

void NumKeyboard::on_rightButton_clicked()      //right
{
int idx = lineEdit->cursorPosition();
if(idx == strContent.length()) //返回此字符串的字符数
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();
}

void NumKeyboard::on_backspaceButton_clicked()      //backspace
{
int idx = lineEdit->cursorPosition();
if(idx == 0)
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.remove(idx-1,1);
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx-1);
lineEdit->setFocus();
}

void NumKeyboard::on_cancelButton_clicked()     //cancel
{
this->close();
valid = false;
}

void NumKeyboard::on_okButton_clicked()         //ok
{
this->close();
valid = true;
}

void NumKeyboard::setText(QString str)      //设置文本内容
{
strContent = str;
lineEdit->setText(strContent);
lineEdit->setFocus();
}

QString NumKeyboard::getText()              //获取内容
{
return strContent;
}

上面的槽函数中只对大体的相似，只对不同处做出讲解

以点击“1”为例：

获取在软键盘中的文本框中光标的位置，赋值给idx，索引用

int idx = lineEdit->cursorPosition();

官方的解释如下

QString x = “Pineapple”;

QString y = x.left(4); // y == “Pine”

同理下面的代码含义是：把当前光标位置左侧所有的数，存放在strContent中，

if判断的作用是，当数值开头是0，便不能够输入。一个简单的检查的功能，例如无法输入”01“

insert的官方解释

QString str = “Meal”;

str.insert(1, QString(“ontr”));

// str == “Montreal”

下面语句的作用是在当前的坐标处出插入1；把新的字符串返回给strContent

（初始时idx=0，光标位置是0）

strContent.insert(idx, ‘1’);

随后设置当前的光标的位置+1，

lineEdit->setCursorPosition(idx+1);

显示光标

lineEdit->setFocus();

void NumKeyboard::on_num1Button_clicked()       //1
{
int idx = lineEdit->cursorPosition();
if(strContent.left(idx) == "0")
{
lineEdit->setCursorPosition(idx);
lineEdit->setFocus();
return;
}
strContent.insert(idx, '1');
lineEdit->setText(strContent);
lineEdit->setCursorPosition(idx+1);
lineEdit->setFocus();

}

在设置正负的时候还会用到 strContent.remove(0, 1);

官方的解释是：

QString s = “Montreal”;

s.remove(1, 4);

// s == “Meal”

上面的含义是，在0的位置删除1个字符。就是数字前面的+、-

在设置右移的槽函数中

idx == strContent.length()) //返回此字符串的字符数

最后通过getText() 函数获取文本的内容

QString NumKeyboard::getText() //获取内容

{

return strContent;

}

void SoftKeyLineEdit::mousePressEvent(QMouseEvent *e)
{
if(e->button() == Qt::LeftButton)
{
numkeyboard->setText(this->text());
numkeyboard->exec();
if(numkeyboard->valid)
{
this->setText(numkeyboard->getText());
}
}
}

我们通过鼠标点击的方式来触发软键盘

下面的函数的作用是：把当前的文本框中的内容传递给软件盘中的文本框

numkeyboard->setText(this->text());

下面的exec()与show()显示的方式有所不同。

exec():

显示一个模式对话框，并且锁住程序直到用户关闭该对话框为止。

show():

显示一个非模式对话框。控制权即刻返回给调用函数。

numkeyboard->exec();

如果点击“确认”按键后 valid返回值是true

if(numkeyboard->valid)

随后把返回得到的字符串，传递到点击处的文本框中。

this->setText(numkeyboard->getText());

如何快速一个上面的软键盘到项目中

1.包含上面的cpp和.h文件

2.通过触发的方式触发下面语句

numkeyboard->setText(this->text());

numkeyboard->exec();

if(numkeyboard->valid)

{

this->setText(numkeyboard->getText());

}

3.触发方式可以是信号（例如clicked()）

另外看还可以是mousePressEvent(); 它的使用方式要重写

细节（QString 定义的strContent存储有引用计数，指向相同的存储空间，仅仅 是增加一个引用计数）

效果图



源代码下载

http://download.csdn.net/detail/osean_li/9773460