目标C:类中get-methods的问题

Question

我有一些课:

@interface SearchBase : NSObject
{
    NSString *words;
NSMutableArray *resultsTitles;
NSMutableArray *resultsUrl;
NSMutableArray *flag;
}

@property (copy, nonatomic) NSString *words;

- (id) getTitleAtIndex:(int *)index;
- (id) getUrlAtIndex:(int *)index;
- (id) getFlagAtIndex:(int *)index;
@end

@implementation SearchBase
 - (id) initWithQuery:(NSString *)words 
{
if (self = [super init])
{
    self.words = words;
}
return self;
}
- (id) getTitleAtIndex:(int *)index
{
return [resultsTitles objectAtIndex:index];
}

- (id) getUrlAtIndex:(int *)index
{
return [resultsUrl objectAtIndex:index];
}

- (id) getFlagAtIndex:(int *)index
{
return [flag objectAtIndex:index];
}
@end

但是当我尝试在子类中使用一些这些get-methods时,我看到:

warning: passing argument 1 of 'getTitleAtIndex:' makes pointer from integer without a cast 
warning: passing argument 1 of 'getFlagAtIndex:' makes pointer from integer without a cast
warning: passing argument 1 of 'getUrlAtIndex:' makes pointer from integer without a cast

并且程序无法正常工作.怎么了？怎么解决？

Answer 1

您正在将整数值传递给您的方法,这是错误的,因为您声明的函数只接受integer pointer不是值的原因,这是警告的原因.objectAtIndex:方法只接受整数值而不是指针,所以如果运行,可能会导致应用程序崩溃.

最简单的方法是更改​​函数中的参数类型.

- (id) getTitleAtIndex:(int )index;
- (id) getUrlAtIndex:(int )index;
- (id) getFlagAtIndex:(int )index;

和函数实现可以类似于下面的函数.

- (id) getTitleAtIndex:(int )index
{
    if(index < [resultsTitles count] )
        return [resultsTitles objectAtIndex:index];
    else
       return nil;
}