QT 笔记 01

最新推荐文章于 2022-05-09 13:24:20 发布

原创最新推荐文章于 2022-05-09 13:24:20 发布 · 576 阅读

0 ·

CC 4.0 BY-SA版权

QT 专栏收录该内容

2 篇文章

订阅专栏

<img src="https://img-blog.youkuaiyun.com/20150816095001612?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQv/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />

Dialog::Dialog(QWidget *parent)
    : QDialog(parent)
{
    label1=new QLabel(this);
    label1->setText(tr("请输入圆的半径："));
    lineEdit=new QLineEdit(this);
    label2=new QLabel(this);
    button=new QPushButton(this);
    button->setText(tr("显示对应圆的面积"));
    QGridLayout *mainLayout=new QGridLayout(this);
    mainLayout->addWidget(label1,0,0);
    mainLayout->addWidget(lineEdit,0,1);
    mainLayout->addWidget(label2,1,0);
    mainLayout->addWidget(button,1,1);
    //connect(button,SIGNAL(clicked()),this,SLOT(showArea()));
    //connect(lineEdit,SIGNAL(textChanged(QString)),this,SLOT(showArea()));
}
void Dialog::showArea()
{
    bool ok;
    QString tempStr;
    QString valueStr=lineEdit->text();
    int valueInt=valueStr.toInt(&ok);
    double area=valueInt*valueInt*PI;
    label2->setText(tempStr.setNum(area));
}

QList 用法

    QList<int> list;
    list<<1<<2<<3<<4<<5;
    QListIterator<int> i(list);
    for(;i.hasNext();)
        qDebug()<<i.next();

QMutableListIterator 用法

    QList<int> list;
    QMutableListIterator<int> i(list);
    for(int j=0;j<10;++j)
        i.insert(j);
    for(i.toFront();i.hasNext();)
        qDebug()<<i.next();
    for(i.toBack();i.hasPrevious();)
    {
        if(i.previous()%2==0)
            i.remove();
        else
            i.setValue(i.peekNext()*10);
    }
    for(i.toFront();i.hasNext();)
        qDebug()<<i.next();
    return 0;
}

    QList<int> list;
    for(int j=0;j<10;j++)
        list.insert(list.end(),j);
    QList<int>::iterator i;
    for(i=list.begin();i!=list.end();++i)
    {
       qDebug()<<(*i);
       *i=(*i)*10;
    }
    QList<int>::const_iterator ci;
    for(ci=list.constBegin();ci!=list.constEnd();++ci)
        qDebug()<<*ci;
    return 0;

QMap 用法

    QMap<QString,QString> map;
    map.insert("beijing","111");
    map.insert("shanghai","021");
    map.insert("nanjing","025");
    QMapIterator<QString,QString> i(map);
    for(;i.hasNext();)
        qDebug()<<"  "<<i.key()<<"  "<<i.next().value();
    QMutableMapIterator<QString,QString> mi(map);
    if(mi.findNext("111"))
        mi.setValue("010");
    QMapIterator<QString,QString> modi(map);
    qDebug()<<"  ";
    for(;modi.hasNext();)
        qDebug()<<" "<<modi.key()<<"  "<<modi.next().value();
    return 0;

QVarient用法：

    QVariant v(709);
    qDebug()<<v.toInt();
    QVariant w("How are you! ");
    qDebug()<<w.toString();
    QMap<QString,QVariant>map;
    map["int"]=709;
    map["double"]=709.709;
    map["string"]="How are you! ";

    map["color"]=QColor(255,0,0);
    qDebug()<<map["int"]<< map["int"].toInt();
    qDebug()<<map["double"]<< map["double"].toDouble();
    qDebug()<<map["string"]<< map["string"].toString();
    qDebug()<<map["color"]<< map["color"].value<QColor>();
    QStringList sl;
    sl<<"A"<<"B"<<"C"<<"D";
    QVariant slv(sl);
    if(slv.type()==QVariant::StringList)
    {
        QStringList list=slv.toStringList();
        for(int i=0;i<list.size();++i)
            qDebug()<<list.at(i);
    }

Algorithms用法：

    double a=-19.3,b=9.7;
    double c=qAbs(a);        //c=19.3
    double max=qMax(b,c);    //max=c=19.3

    int bn=qRound(b);        //bn=10
    int cn=qRound(c);        //cn=19

    qDebug()<<"a="<<a;
    qDebug()<<"b="<<b;
    qDebug()<<"c=qAbs(a)= "<<c;
    qDebug()<<"qMax(b,c)= "<<max;
    qDebug()<<"bn=qRound(b)= "<<bn;
    qDebug()<<"cn=qRound(c)= "<<cn;

    qSwap(bn,cn);
    qDebug()<<"qSwap(bn,cn)："<<"bn="<<bn<<" cn="<<cn;

    return 0;