qt多个按钮关联同一个处理函数（槽函数） sender()

一、qobject_cast用法：

功能：类似于强制转换

T qobject_cast(const QObject *object)

Example:

  QObject *obj = new QTimer;          // QTimer inherits QObject

  QTimer *timer = qobject_cast<QTimer *>(obj);
  // timer == (QObject *)obj

  QAbstractButton *button = qobject_cast<QAbstractButton *>(obj);
  // button == 0

T的类型必须是直接或者间接继承QObject  

二、在槽函数如何知道是哪个按键按下

QpushButton *btn = qobject_cast<QpushButton *>(sender());  //把发信号的对象转换为按钮类型