使用 CGPoint 追踪长按手势的确切位置

通过使用 CGPoint 位置，它始终保存 uiscrollview 中的最后一个图像。当我点击其他图像进行保存时。我该怎么做才能保存我点击的确切图像。

UIScrollView *imageScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
imageScrollView.pagingEnabled = YES;

NSInteger numberOfViews = 61;

for (int i = 0; i < numberOfViews; i++) {

    CGFloat xOrigin = i * self.view.frame.size.width;

 NSString *imageName = [NSString stringWithFormat:@"image%d.png", i];

    _image = [UIImage imageNamed:imageName];

    _imageView = [[UIImageView alloc] initWithImage:_image];

    _imageView.frame = CGRectMake(xOrigin, 0, self.view.frame.size.width, self.view.frame.size.height);

 UILongPressGestureRecognizer *gestureRecognizer = [[UILongPressGestureRecognizer alloc]
                                                       initWithTarget:self
                                                       action:@selector(handleLongPress:)];

    imageScrollView.userInteractionEnabled = YES;
    [imageScrollView addGestureRecognizer:gestureRecognizer];
    gestureRecognizer.delegate = self;
    [gestureRecognizer release];

    [imageScrollView addSubview:_imageView];
imageScrollView.contentSize = CGSizeMake(self.view.frame.size.width * numberOfViews, self.view.frame.size.height);

    - (void)handleLongPress:(UILongPressGestureRecognizer*)gestureRecognizer{
if (gestureRecognizer.state == UIGestureRecognizerStateBegan){
    UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:nil delegate:self cancelButtonTitle:@"Cancel" destructiveButtonTitle:nil otherButtonTitles:@"Save Photo", nil];
    actionSheet.actionSheetStyle = UIActionSheetStyleBlackTranslucent;
    [actionSheet showInView:self.view];
    [actionSheet release];

     }}

 -(void)actionSheet:(UIActionSheet *)actionSheet clickedButtonAtIndex:(NSInteger)buttonIndex {

switch (buttonIndex) {
    case 0:
        [self savePhoto];

       break;

    default:
        break;

}

   -(void)savePhoto{

CGPoint location = [gesture locationInView:_imageView];

if  (CGRectContainsPoint(_imageView.bounds, location)){

UIImageWriteToSavedPhotosAlbum(_image, self, @selector(image: didFinishSavingWithError:contextInfo:), nil);
   }}}

任何想法将不胜感激。

Thanks

该点将始终出现在范围内UIScrollView其中LongPressGestureRecognizer被触发。你应该检查你的滚动视图contentOffset (use contentOffset.x对于水平布局和contentOffset.y对于垂直布局）来检测您应该保存哪个图像。

此外，您还可以将触摸点转换为UIImageView实例的局部坐标系并查看该点是否位于图像视图的范围内bounds rect.

UPDATE

例如，您可以使用类似的方法来检测该点是否在图像视图的边界内（注意：我有not测试了这一点，这是假设有多个图像视图添加到滚动视图中）：

if (CGRectContainsPoint(_imageView.bounds, [self.view convertPoint:location toView:_imageView]))
{
    // do something
}

您还应该考虑检测之前应保存哪个图像，并在显示之前存储对该图像的引用UIActionSheet对用户来说，因为它可能会减少您可能遇到的潜在问题的数量，并且以后更容易阅读，但这是我的主观意见。