錯誤：索引1超出了空數組的邊界

Question

我創建了一個NSMutableArray來在那裏存儲一些字符。當我添加一些字符時，它會給我一個錯誤。這裏我的代碼：

@property(strong,nonatomic) NSMutableArray *actions;  < ViewController.h 

@synthesize actions;          < ViewController.m 


actions = [[NSMutableArray alloc]init];  
switch ([sender tag]) { 
     case 0: 
      currentLabel = water; 
      [actions insertObject:@"0" atIndex:i]; 
      i++; 
      break; 
     case 1: 
      currentLabel = coke; 
      [actions insertObject:@"1" atIndex:i]; 
      i++; 
      break; 
     case 2: 
      currentLabel = fanta; 
      [actions insertObject:@"2" atIndex:i]; 
      i++; 
      break; 
}  

Answer 1

改爲使用[actions addObject:@"X"]。如果數組沒有元素，則不能在索引1處插入對象。