iOS 文件大小转换成 KB、MB、GB 。。。

-(NSString *) convertFileSize:(long long)size {
    long kb = 1024;
    long mb = kb * 1024;
    long gb = mb * 1024;

    if (size >= gb) {
        return [NSString stringWithFormat:@"%.1f GB", (float) size / gb];
    } else if (size >= mb) {
        float f = (float) size / mb;
        if (f > 100) {
            return [NSString stringWithFormat:@"%.0f MB", f];
        }else{
            return [NSString stringWithFormat:@"%.1f MB", f];
        }
    } else if (size >= kb) {
        float f = (float) size / kb;
        if (f > 100) {
            return [NSString stringWithFormat:@"%.0f KB", f];
        }else{
            return [NSString stringWithFormat:@"%.1f KB", f];
        }
    } else
        return [NSString stringWithFormat:@"%lld B", size];
}