//獲取一個視圖的快照
- (UIImage *)getImageFromView:(UIView *)view{
    float width = [UIScreen mainScreen].bounds.size.width;
    float height = [UIScreen mainScreen].bounds.size.height;
    
    UIGraphicsBeginImageContext(CGSizeMake(width, height));
    CGContextRef context = UIGraphicsGetCurrentContext();
    [view.layer renderInContext:context];
    
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

//保存圖片到相冊
- (void)saveImageToAlbum:(UIImage *)image
{
   UIImageWriteToSavedPhotosAlbum(image, self, nil, nil); 
}

//保存圖片到本地
- (void)saveImageToDisk:(UIImage *)image
{
    NSString *dir = [NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES) objectAtIndex:0];
    NSString *path = [NSString stringWithFormat:@"%@/pic_%f.png",dir,[NSDate timeIntervalSinceReferenceDate]];
    NSData *data = [NSData dataWithData:UIImagePNGRepresentation(image)];
    [data writeToFile:path atomically:YES];
}


+ (UIColor *) colorWithHexString: (NSString *) stringToConvert
{
  NSString *cString = [[stringToConvert stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]] uppercaseString]; //去掉前後空格換行符
  
  // String should be 6 or 8 characters
  if ([cString length] < 6) return [UIColor redColor];
  
  // strip 0X if it appears
  if ([cString hasPrefix:@"0X"]) cString = [cString substringFromIndex:2];
  if ([cString hasPrefix:@"#"]) cString = [cString substringFromIndex:1];
  if ([cString length] != 6) return [UIColor redColor];
  // Separate into r, g, b substrings
  NSRange range;
  range.location = 0;
  range.length = 2;
  NSString *rString = [cString substringWithRange:range];
  
  range.location = 2;
  NSString *gString = [cString substringWithRange:range];
  
  range.location = 4;
  NSString *bString = [cString substringWithRange:range];
  
  // Scan values
  unsigned int r, g, b;
  [[NSScanner scannerWithString:rString] scanHexInt:&r];  //掃描16進制到int
  [[NSScanner scannerWithString:gString] scanHexInt:&g];
  [[NSScanner scannerWithString:bString] scanHexInt:&b];
  
  return [UIColor colorWithRed:((float) r / 255.0f)
                         green:((float) g / 255.0f)
                          blue:((float) b / 255.0f)
                         alpha:1.0f];
}