如何获取 UIImage 的大小（以 KB 为单位）？

Question

有没有办法从 UIImage 获取以 KB 为单位的文件大小，而不从 didFinishPickingMediaWithInfo 获取该图像？所呈现的图像来自相册。

我尝试了以下代码，但这给出了以下结果：图像大小（KB）：0.000000

- (void)setImage:(UIImage *)image
{
    _image = image;
    self.imageView.image = image;
}

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        [self setupView];

        self.backgroundColor = [UIColor whiteColor];

        panGestureRecognizer = [[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(beingDragged:)];
        [self addGestureRecognizer:panGestureRecognizer];

        // prepare image view
        self.imageView = [[UIImageView alloc]initWithFrame:self.bounds];
        self.imageView.clipsToBounds = YES;
        self.imageView.contentMode = UIViewContentModeScaleAspectFill;
        [self addSubview:self.imageView];



        NSData *imgData = [[NSData alloc] initWithData:UIImageJPEGRepresentation((_image), 0.5)];
        int imageSize = imgData.length;
        NSLog(@"size of image in KB: %f ", imageSize/1024.0);

        overlayView = [[OverlayView alloc]initWithFrame:CGRectMake(self.frame.size.width/2-100, 0, 100, 100)];
        overlayView.alpha = 0;
        [self addSubview:overlayView];


    }
    return self;
}

Answer 1

以下是计算主目录或文档中文件大小的示例：

NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *filePath = [documentsDirectory stringByAppendingPathComponent:@"yourimagename.png"]

文件sie计算：

       filesize = [[[NSFileManager defaultManager] attributesOfItemAtPath:filePath error:nil] fileSize];

       NSLog(@"%lld",filesize);

在添加文件大小之前，您可以将其添加到 .m 文件中

@interface ViewController () {
long long filesize;
}

这将产生字节，如果您尝试将这些字节转换为 kb，您可以使用 NSByteCountFormatter，它会为您处理所有数学运算：

 NSByteCountFormatter *sizeFormatter = [[NSByteCountFormatter alloc] init];
sizeFormatter.countStyle = NSByteCountFormatterCountStyleFile;

然后这样称呼它：

[sizeFormatter stringFromByteCount:filesize]

如果图像没有保存在磁盘上，您可以这样计算大小：

NSData *imgData = UIImageJPEGRepresentation(_image, 1);
filesize = [imgData length]; //filesize in this case will be an int not long long so use %d to NSLog it