2010-07-01 74 views
0

澄清我有以下代碼(這兩個項目和itemsCopy是NSMutableArray的公司):需要對addObjectsFromArray功能

//DO: populate items w/ 30 elements 
[self.itemsCopy addObjectsFromArray:self.items]; 
//DO: remove all elements in items 

結果

Begin Pass 1: 
itemsCopy = 0 
items = 30 

End Pass 1: 
itemsCopy = 30 
items = 0 

Begin Pass 2: 
itemsCopy = 0 
items = 30 

End Pass 2: 
itemsCopy = 30 
items = 0 

我怎樣才能不斷追加項目itemsCopy的結束?我想場景是這樣的:

Begin Pass 1: 
itemsCopy = 0 
items = 30 

End Pass 1: 
itemsCopy = 30; 
items = 0; 

Begin Pass 2: 
itemsCopy = 30 
items = 30 

End Pass 2: 
itemsCopy = 60 
items = 0 
+3

某處您必須重新初始化itemsCopy數組,或者每次執行不同對象上的操作時都需要重新初始化.... – ennuikiller 2010-07-01 00:33:07

+1

so addObjectsFromArray should always append? – 2010-07-01 01:43:26

+0

希漢阿拉姆:是的。請參閱文檔:http://developer.apple.com/iphone/library/documentation/Cocoa/Reference/Foundation/Classes/NSMutableArray_Class/Reference/Reference.html#//apple_ref/occ/instm/NSMutableArray/addObjectsFromArray:無處它說它會重置陣列,也沒有任何理由。 – 2010-07-01 12:05:24

回答

3

通過保持你只是填補了itemsCopy屬性相同的數組。顯然,無論您使用什麼方法,都將重置爲空數組。