ios - 如何在 iOS 中将图像从资源中分离出来

Question

我正在我的应用程序中显示一组图像。当我从资源文件夹加载图像时，代码可以正常工作，如下所示:

- (void)viewDidLoad
{

    NSMutableArray *array = [[NSMutableArray alloc] init];                          

    [array addObject:[NSString stringWithFormat: @"pic_a"]];     
    [array addObject:[NSString stringWithFormat: @"pic_b"]];    
    [array addObject:[NSString stringWithFormat: @"pic_c"]];     
    [array addObject:[NSString stringWithFormat: @"pic_d"]];     


    int index = arc4random() % [array count];

    NSString *pictureName = [array objectAtIndex:index];  


    NSString* imagePath = [ [ NSBundle mainBundle] pathForResource:pictureName ofType:@"png"];

    UIImage *img = [ UIImage imageWithContentsOfFile: imagePath];

    if (img != nil) { // Image was loaded successfully.
        [imageView setImage:img];
        [imageView setUserInteractionEnabled:NO];   
        [img release]; // Release the image now that we have a UIImageView that contains it.
    }

    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
}

但是，如果我在“资源”组中创建一个“图像”组，并尝试从那里加载图像， View 中的图像将显示为空白。

[array addObject:[NSString stringWithFormat: @"images/pic_a"]];     
[array addObject:[NSString stringWithFormat: @"images/pic_b"]];    
[array addObject:[NSString stringWithFormat: @"images/pic_c"]];     
[array addObject:[NSString stringWithFormat: @"images/pic_d"]];

我想将图像从 nib 文件和所有其他文件中分离出来。最好的方法是什么？

Answer 1

即使您将图像放在资源中的单独组中，您也可以通过调用名称来加载它们，例如使用这一行

UIImage *img = [UIImage imageNamed:[array objectAtIndex:index]];

代替这三行:

NSString *pictureName = [array objectAtIndex:index];  
NSString* imagePath = [ [ NSBundle mainBundle] pathForResource:pictureName ofType:@"png"];
UIImage *img = [ UIImage imageWithContentsOfFile: imagePath];

您仍然可以简单地填充数组

[array addObject:[NSString stringWithFormat: @"pic_a"]];

如果您同时拥有 jpg 和 png 文件，则应将 .png 附加到文件名末尾。否则，将其关闭即可。