鼠标点中一项时,QListWidget会发出这信号的,可以用
void currentItemChanged ( QListWidgetItem * current, QListWidgetItem * previous )
void currentRowChanged ( int currentRow )
void currentTextChanged ( const QString & currentText )
void itemActivated ( QListWidgetItem * item )
void itemChanged ( QListWidgetItem * item )
void itemClicked ( QListWidgetItem * item )
void itemDoubleClicked ( QListWidgetItem * item )
void itemEntered ( QListWidgetItem * item )
void itemPressed ( QListWidgetItem * item )
void itemSelectionChanged ()
这些信号来取得当前点了哪一项,具体看文档