第8课 启航！第一个应用实例

QWidget w;        //生成QWidget对象，顶级组件
QLineEdit le(&w); //生成QLineEdit对象，其父组件为QWidget

le.setAlignment(Qt::AlignRight); //设置显示的字符串右对齐
le.move(10, 10);                 //移动坐标(10, 10)
le.resize(240, 30);              //设置大小width=240,height=30

#include <QApplication>
#include <QWidget>
#include <QLineEdit>
#include <QPushButton>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    QWidget* w = new QWidget(NULL, Qt::WindowCloseButtonHint);
    QLineEdit* le = new QLineEdit(w);//le的生命期由父组件来管理
    QPushButton* button[20] = {0};
    const char* btnText[20] =
    {
        "7", "8", "9", "+", "(",
        "4", "5", "6", "-", ")",
        "1", "2", "3", "*", "←",
        "0", ".", "=", "/", "C",
    };

    int ret = 0;

    le->move(10, 10);
    le->resize(240, 30);
    le->setReadOnly(true); //设置编辑框的只读属性

    for(int i = 0; i < 4; i++)
    {
        for(int j = 0; j< 5; j++)
        {
            button[i * 5 + j] = new QPushButton(w);//按钮的生命期由父组件来管理
            button[i * 5 + j]->resize(40, 40);
            button[i * 5 + j]->move(10 + j * 50, 50 + i * 50);
            button[i * 5 + j]->setText(btnText[i * 5 + j]);
        }
    }

    w->show();
    w->setFixedSize(w->width(), w->height()); //固定窗口大小

    ret = a.exec();

    delete w;

    return ret;
}