Question

在“处理”《应用规划指南》中“处理复杂多功能”的示范守则提供了一个不完整的范例,假设读者充分了解这些空白。我非常清楚,我没有足够了解这一点,而没有澄清。

在列出3-6时,我假定<代码>touch Begin Points是CFDictionaryRef的成员财产。更正?



在同一例子中,我们重新使用了malloc(),因此,我认为我们需要在稍后某个时候打电话free(<>/code>。 我的问题是我释放了什么? 是否应在<条码>上注明各个点:。 我如何这样做? (我假定需要在列举上读) 或者,Ifree(touch Begin Points); in my dealloc: methods?


最后,在清单3-7中,有<代码>compareAddress:方法。 我如何(以及在何处)执行?

<>Update>  回答。

Answer 1

Yes, touchBeginPoints is a member property of type CFDictionaryRef.

You wouldn t call free on an instance of CFDictionaryRef, but rather CFRelease. (CoreFoundation s memory management is similar to Objective-C s with explicit reference counting via retain/release semantics.)

You may want to read "Collection Programming Topics for Core Foundation" to get a stronger feel for CFMutableDictionary. http://developer.apple.com/mac/library/documentation/CoreFoundation/Conceptual/CFCollections/CFCollections.html
As for freeing the keys, you probably want to pass in a custom release callback when you create the dictionary. The key release callback is called for each element in the dictionary when the dictionary itself is released. (See the last two parameters to CFMutableDictionaryCreate for more.)

www.un.org/Depts/DGACM/index_spanish.htm 想像:

 @interface UITouch (TouchSorting)
 - (NSComparisonResult)compareAddress:(id)obj;
 @end

 @implementation UITouch (TouchSorting)
 - (NSComparisonResult)compareAddress:(id)obj {
     if ((void *)self < (void *)obj) return NSOrderedAscending;
    else if ((void *)self == (void *)obj) return NSOrderedSame;
    else return NSOrderedDescending;
 }
 @end

友情链接