从头到尾循环 uiimages 的 Nsmutable 数组

发布于 2024-12-27 05:09:08 字数 162 浏览 2 评论 0原文

我有一个 NSMUtable 图像数组，其中使用上一个和下一个按钮显示不同的图像，但是当我到达数组末尾时，模拟器崩溃了。我想将数组的末尾循环到开头，这样当我到达图像数组的末尾时，当我再次点击下一个按钮时，它会循环回到第一个图像，当我点击第一个图像时，它也会循环到第一个图像上一个按钮循环到最后一个图像，没有崩溃

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又爬满兰若 2025-01-03 05:09:08

你想要的是一个循环数组，使用标准的 NSMutableArray 很容易实现。例如，假设您将图像存储在名为 imageArray 的数组中，并使用一个简单的变量来跟踪当前图像的索引，例如：

int currentImageIndex = 0;

...那么您可以实现 nextImage< /code> 和 previousImage 类似：

- (UIImage*) nextImage {
    currentImageIndex = (currentImageIndex + 1) % [imageArray count];
    return [imageArray objectAtIndex:currentImageIndex];
}

- (UIImage*) previousImage {
    currentImageIndex--;
    if (currentImageIndex < 0) {
        currentImageIndex = [imageArray count] - 1;
    }

    return [imageArray objectAtIndex:currentImageIndex];
}

然后只要你想单步遍历数组，就使用 nextImage 和 previousImage ，问题就解决了。

What you want is a circular array, which is easy to implement using a standard NSMutableArray. For instance, say you store your images in an array called imageArray and use a simple variable to keep track of the index of your current image, like:

int currentImageIndex = 0;

...then you might implement nextImage and previousImage like:

- (UIImage*) nextImage {
    currentImageIndex = (currentImageIndex + 1) % [imageArray count];
    return [imageArray objectAtIndex:currentImageIndex];
}

- (UIImage*) previousImage {
    currentImageIndex--;
    if (currentImageIndex < 0) {
        currentImageIndex = [imageArray count] - 1;
    }

    return [imageArray objectAtIndex:currentImageIndex];
}

Then just use nextImage and previousImage whenever you want to step through the array, and problem solved.

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颜 2025-01-03 05:09:08

很简单就能做到。您需要做的就是创建一个检查来查看是否位于最后一个元素，如果是，则再次将跟踪器（如 count 或 i 等）设置为 0，

这是伪代码
//设置索引

if ( array [ index ] == len(array) - 1) //at end
{
  index = 0
}

if(array [index] == -1)//at beginning
{
  index = len(array) -1
}
// do something with array[index]

Simple enough to do. all you need to do is create a check to see if you're on the last element, and if so, set your tracker (like count or i etc) to 0 again,

Heres the psudo code
//set index

if ( array [ index ] == len(array) - 1) //at end
{
  index = 0
}

if(array [index] == -1)//at beginning
{
  index = len(array) -1
}
// do something with array[index]

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幽梦紫曦～ 2025-01-03 05:09:08

我想提出这个解决方案：

所选 UIImage 的属性，保存当前索引的 NSInteger 属性。

-(IBAction) nextButtonTapped:(id)sender
{
    self.currentIndex = self.currentIndex++ % [self.images count];
    self.selectedImage= [self.images objectAtIndex:self.currentIndex];
    [self reloadImageView];
}

-(IBAction) previousButtonTapped:(id)sender
{
    self.currentIndex--;
    if (self.currentIndex < 0)
        self.currentIndex += [self.images count];
    self.selectedImage= [self.images objectAtIndex:self.currentIndex];
    [self reloadImageView];
}

-(void)reloadImageView
{
    //do, what is necessary to display new image. Animation?

}

I want to propose this solution:

A property for the selected UIImage, a NSInteger property to hold the current index.

-(IBAction) nextButtonTapped:(id)sender
{
    self.currentIndex = self.currentIndex++ % [self.images count];
    self.selectedImage= [self.images objectAtIndex:self.currentIndex];
    [self reloadImageView];
}

-(IBAction) previousButtonTapped:(id)sender
{
    self.currentIndex--;
    if (self.currentIndex < 0)
        self.currentIndex += [self.images count];
    self.selectedImage= [self.images objectAtIndex:self.currentIndex];
    [self reloadImageView];
}

-(void)reloadImageView
{
    //do, what is necessary to display new image. Animation?

}

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