错误：索引1超出了空数组的边界

Question

我创建了一个NSMutableArray来在那里存储一些字符。当我添加一些字符时，它会给我一个错误。这里我的代码：

@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

改为使用[actions addObject:@"X"]。如果数组没有元素，则不能在索引1处插入对象。