Question

我在NSMutableArray中创建了两个viewDidLoad，我将其添加到NSMutableDictionary中。当我试着用一个阵列洗牌时，没关系。但问题是，当Im独立地移动两个阵列时，它无法正常工作，不知何故索引混淆了。

这是我的数组代码（第一个数组）：

self.items1 = [NSMutableArray new];

for(int i = 0; i <= 100; i++) 
{ 

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *documentsDir = [paths objectAtIndex:0];

    NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:@"[Images%d.png", i]]; 
    if([[NSFileManager defaultManager] fileExistsAtPath:savedImagePath]){ 
        self.container = [[NSMutableDictionary alloc] init];
        [container setObject:[UIImage imageWithContentsOfFile:savedImagePath] forKey:@"items1"]; 
        [container setObject:[NSNumber numberWithInt:i] forKey:@"index1"];
        [items1 addObject:container];           
    } 
} 

NSLog(@"Count : %d", [items1 count]);  

[items1 enumerateObjectsUsingBlock:^(id object, NSUInteger index, BOOL *stop) {
    NSLog(@"%@ images at index %d", object, index);
}];

（第二阵）：

self.items2 = [NSMutableArray new];  
for(int i = 0; i <= 100; i++) 
{ 

    NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
    NSString *documentsDir = [paths objectAtIndex:0];

    NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:@"secondImages%d.png", i]]; 
    NSLog(@"savedImagePath=%@",savedImagePath);
    if([[NSFileManager defaultManager] fileExistsAtPath:savedImagePath]){ 
        self.container = [[NSMutableDictionary alloc] init];
        [container setObject:[UIImage imageWithContentsOfFile:savedImagePath] forKey:@"items2"]; 
        [container setObject:[NSNumber numberWithInt:i] forKey:@"index2"];
        [items2 addObject:container];
    } 
} 

NSLog(@"Count : %d", [items2 count]);  

[items2 enumerateObjectsUsingBlock:^(id object, NSUInteger index, BOOL *stop) {
    NSLog(@"%@ images at index %d", object, index);
}];

我对使用我的数组的iCarousel的看法：

- (UIView *)carousel:(iCarousel *)carousel viewForItemAtIndex:(NSUInteger)index reusingView:(UIView *)view
{

    if (carousel == carousel1)
    {
        NSDictionary *obj = [items1 objectAtIndex:index];
        view = [[UIImageView alloc] initWithImage:[obj objectForKey:@"items1"]];
        view.tag = index;
    }
    else
    {
        NSDictionary *obj = [items2 objectAtIndex:index];
        view = [[UIImageView alloc] initWithImage:[obj objectForKey:@"items2"]];
        view.tag = index;
    }

    return view;
}

然后我的shuffle代码（我尝试复制其他数组，但也没有工作）：

   srandom(time(NULL));
    NSUInteger count = [items1 count];
    for (NSUInteger i = 0; i < count; ++i) {
        int nElements = count - i;
        int n = (random() % nElements) + i;
        [items1 exchangeObjectAtIndex:i withObjectAtIndex:n];
    }

如何使用上面的代码（或者如果你有其他建议）将它与两个数组混合？感谢

我的另一个问题是当我尝试将类子类化为shuffle方法或者使用上面的代码时，它们的索引是混合的。例如：

对象：苹果，球，胡萝卜，狗

索引：1 2 3 4

但在我的视图中洗牌：

对象：胡萝卜，苹果，狗，balle

索引：2 4 1 3

我还有一个方法，当旋转木马停止时，它会删除视图上的图像。

Answer 1

最干净的解决方案：使用Objective-C Category

的NSMutableArray + RandomUtils.h

#import <Foundation/Foundation.h>


@interface NSMutableArray (RandomUtils) 
-(void)shuffle;
@end

的NSMutableArray + RandomUtils.m

#import "NSMutableArray+RandomUtils.h"

@implementation NSMutableArray (RandomUtils)
-(void)shuffle
{
    NSUInteger count = [self count];
    for (NSUInteger i = 0; i < count; ++i) {
        NSUInteger nElements = count - i;
        NSUInteger n = (arc4random() % nElements) + i;
        [self exchangeObjectAtIndex:i withObjectAtIndex:n];
    }
}

@end

导入它，无论你在哪里洗牌MSMutableArray

[array1 shuffle];
[array2 shuffle];

我试图重现你的混合索引问题，但我不能

NSMutableArray *sarray = [NSMutableArray arrayWithArray: @[@"carrots", @"apple", @"dog", @"balle"]];

NSLog(@"%@", sarray);
[sa enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    NSLog(@"%@ object at index %lu", obj, idx);
}];

[sarray shuffle];
 NSLog(@"%@", sarray);
[sarray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    NSLog(@"%@ object at index %lu", obj, idx);
}];

结果

(
    carrots,
    apple,
    dog,
    balle
)
carrots object at index 0
apple object at index 1
dog object at index 2
balle object at index 3
 (
    balle,
    dog,
    carrots,
    apple
)
balle object at index 0
dog object at index 1
carrots object at index 2
apple object at index 3

BTW：你的例子是不正确的：在数组中有四个对象，索引应该从0开始，最大值是3.你有1和4。

所以数组被洗牌并且索引正常。你必须在代码中遇到一些其他问题，而你没有显示。

你应该放弃真正的代码。

如果我明白，我仍然不确定你想要什么。但是从你的评论中我假设，你想要改组数组但保留旧指数。这是不可能的，因为索引是数组内对象的位置。但是你总是可以自由地将原始索引保存在某个地方或者你只是复制一个数组，洗牌其中一个。现在，ho可以在两个数组中询问对象的索引。

NSArray *originalArray =  @[@"carrots", @"apple", @"dog", @"balle"];

NSLog(@"%@", originalArray);
[originalArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    NSLog(@"%@ object at index %lu", obj, idx);
}];


NSArray *shuffledArray = [originalArray arrayShuffled];
 NSLog(@"%@", shuffledArray);
[shuffledArray enumerateObjectsUsingBlock:^(id obj, NSUInteger idx, BOOL *stop) {
    NSLog(@"%@ object at index %lu %lu", obj, idx, [originalArray indexOfObject:obj]);
}];

Answer 2

假设想法是以相同的顺序对两个数组进行洗牌，那么你只需要在第一个数组之后立即交换第二个数组？

NSUInteger count = [items1 count];
for (NSUInteger i = 0; i < count; ++i) {
    int nElements = count - i;
    int n = (random() % nElements) + i;
    [items1 exchangeObjectAtIndex:i withObjectAtIndex:n];
    [items2 exchangeObjectAtIndex:i withObjectAtIndex:n];
}

Answer 3

假设您有两个不同的图像阵列需要随机播放图像。

 for(int i = 0; i <= 100; i++) 
    {
      NSArray *paths = NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES);
        NSString *documentsDir = [paths objectAtIndex:0];

        NSString *savedImagePath = [documentsDir stringByAppendingPathComponent:[NSString stringWithFormat:@"[Images%d.png", i]]; 
        if([[NSFileManager defaultManager] fileExistsAtPath:savedImagePath]){ 
//Lazy initialization of dictionary 
            NSMutableDictionary *dict = [[NSMutableDictionary alloc] init];
            [dict setObject:[UIImage imageWithContentsOfFile:savedImagePath] forKey:@"items1"]; 
            [dict setObject:[NSNumber numberWithInt:i] forKey:@"index1"];
            [items1 addObject:dict]; 
    [dict release];          
        } 
    }

以相同的方式将对象添加到第二个数组。

NSUInteger count = [items1 count];
for(int i = 0 ;i < count; i++)
{
int nElements = count - i;
int n = (random() % nElements) + i;
[items1 exchangeObjectAtIndex:i withObjectAtIndex:n];
}

第二阵列改组

 NSUInteger count = [items2 count];
    for(int i = 0 ;i < count; i++)
    {
    int nElements = count - i;
    int n = (random() % nElements) + i;
    [items2 exchangeObjectAtIndex:i withObjectAtIndex:n];
    }

这应该有效。如果您仍然发现问题请告诉我。

单独随机播放两个NSMutableArray

3 个答案: