關於圖像顯現的問題

[muddy]

我把一個Label 顯像了第一個 Pixmap 顯現出來
可是要按pushbutton改成顯像成第二個Pixmap的時候就不行了

QObject::connect(pushButton, SIGNAL(clicked(bool)), label,SLOT(setPixmap(pixmap2)));
QObject::connect(pushButton_2, SIGNAL(clicked(bool)), label, SLOT(clear()));

SLOT連結的設定裡面 pushButton_2 可以將圖像清掉
但是 pushButton 卻不能重新跑出另外一張圖

可以請問是哪邊出了問題嗎？

[cavendish]

it's wrong for the first line in your code

http://doc.trolltech.com/4.2/signalsandslots.html
http://www.qiliang.net/qt/signalsandslots.html

The signals and slots mechanism is type safe: The signature of a signal must match the signature of the receiving slot. (In fact a slot may have a shorter signature than the signal it receives because it can ignore extra arguments.)
信号和槽的机制是类型安全的：一个信号的签名必须与它的接收槽的签名相匹配。（实际上一个槽的签名可以比它接收的信号的签名少，因为它可以忽略额外的签名。）