1:如果无法保证子类行为的一致性,那么就用委托
If the subClass cann't keep with superClass,use delegate rather than inheritance.If the subClass cann't keep
1:如果无法保证子类行为的一致性,那么就用委托
If the subClass cann't keep with superClass,use delegate rather than inheritance.If the subClass cann't keep