I'd like to recreate a view that you can zoom like the iPhone/iPad Mail app or Sparrow when viewing an email, where at the top there is block of information and then a UIWebView. I can obviously do this easily in interface builder or code, BUT I would like it behave like the Mail app.
By 'like the Mail App' I mean, when you pinch zoom (anywhere in the view), the UIWebView is the only view that actually zooms, and the top content stays the same size. When you zoom out too far and see the background the whole view zooms out (not just the UIWebview) and the whole view scrolls too.
I've done some experimenting and tried some of the suggestions already, like inserting the top view at the top of the UIWebView, extending the height of the UIWebView based on content size but this always ends up with either the top view zooming too, OR just the UIWebView.
I hope the makes some sense. It might be really simple but I've been trying to sort this for a while on and off that I can't see the wood for the trees any more.
This is for a MonoTouch app, but if anyone has Objective-C examples or anything I can convert and post back.
I have done just that for our application; it is not as simple as it sounds, but on iOS 5 it should be somewhat less complex than iOS 4.
Have a view of the top part you wish to have constant. When your web view finishes loading the HTML and renders it, get the scrollView of the web view, and add your view as a subview to that. Add the top view's frame height to the contentSize.height of the scroll view, and add the height to origin.y of the rest of subviews of the scroll view (those that are not your top view). Set your view controller as the delegate of the web view's scroll view. Whenever the user scrolls:
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGRect frame = contentView.frame;
if(scrollView.contentOffset.x < 0)
{
frame.origin.x = 0;
}
else if((scrollView.contentOffset.x + contentView.frame.size.width) > scrollView.contentSize.width)
{
frame.origin.x = scrollView.contentSize.width - contentView.frame.size.width;
}
else
{
frame.origin.x = scrollView.contentOffset.x;
}
[contentView setFrame:frame];
}
This should make it behave exactly like the mail.app view.
Related
I'm creating a scroll view for displaying a very large view, and I need both scroll and zoom functionality (just like an image viewer). Here are the steps that I've taken:
In interface builder, I've put a scroll viewer to the view controller.
I've added a pinch gesture recognizer to the scroll viewer.
I've connected the gesture recognizer's action to the code to handle the gesture events.
When the view controller is loaded, I change my view's origin to the center (viewer is my scroll viewer): self.viewer.contentOffset = CGPointMake(384, 512);
In my code for the handler, I handled the event as such:
(startScale is 1.0 in the beginning)
- (IBAction)handlePinch:(UIPinchGestureRecognizer *)sender {
if(sender.state == UIGestureRecognizerStateEnded){
startScale *= sender.scale;
}else{
float result = sender.scale * startScale;
self.viewer.transform = CGAffineTransformMakeScale(result, result);
}
}
When I run the app, the gesture is recognized and scaling works correctly, however, the whole view scales with respect to the 0,0 point of the screen (top left). I want it to scale with respect to the middle point that I'm applying the gesture, just as a natural pinch gesture for zooming into a photo.
I've also tried setting self.viewer.frame's origin, but nothing changed. I've searched about the problem and found these:
How to set a UIView's origin reference? (already tried)
https://stackoverflow.com/questions/13163279/pinch-punch-gestures-center (about my problem, but unanswered)
UIPinchGestureRecognizer for zooming and panning an image in xcode (looks like an overkill, too complicated for me, and I'm not sure if this would really help my situation)
How can I achieve natural pinching with my scroll view, what am I doing wrong?
Thanks,
Can.
Well, the answer to the problem is very simple: Remove the pinch gesture altogether. The benefit of using a UIScrollView is that it handles the panning/zooming internally, and you have to do nothing
Edit: To make sure the content is scaled properly, you are going to need a UIView (called contentView or whatever you want) where you put all the content, and then on the delegate method of your UIScrollView do this:
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView {
return contentView;
}
This should solve your problem
Edit 2: Also remember to set the minimum / maximum zoom scales for your UIScrollView
I have the following layout (see below), which for most circumstances works just fine. The user is able to scroll within the blue UIScrollView (which for all intents and purposes is a UITableView, but this question generalises this), and then when they've reached the end of this scroll view, they can start scrolling again (they have to take their finger off, and on again, because the inner scroll view rubberbands otherwise), and the 'super' scroll view starts scrolling, revealing the rest of the image.
It's the whole (they have to take their finger off, and on again, because the inner scroll view rubberbands otherwise) that I don't want. Ideally, once the contained UIScrollView reaches the end of its content, I want the superview to take over scrolling straight away, so that the inner scroll view doesn't rubberband.
The same goes when the user is scrolling back up; when the red scrollview reaches the top of it's content, I want the inner blue scroll view to start scrolling up straight away, instead of the red scroll view rubberbanding at the top.
Any idea how? I am able to determine when the scroll views have reached the ends of their content, but I'm not sure how to apply this knowledge to achieve the effect I'm after. Thanks.
// Inner (blue) scroll view bounds checking
if (scrollView.contentOffset.y + scrollView.frame.size.height > scrollView.contentSize.height) { ... }
// Outer (red) scroll view bounds checking
if (scrollView.contentOffset.y < 0) { ... }
Yeah. Ive got a nifty trick for you.
Instead of having your red outlined view a scrollview make it a normal UIView that fills the screen. In that view lay out your scroll view (table view) and image view as they are in your illustration.
Place a scrollview that fills the bounds of the root view (i.e. also fills the screen) above all the other scrollview and image views. Set the content size of this view to be the total content height of all the views you want to scroll through. In otherwords there is an invisible scrollview sitting on top of all your other views and its content size height is inner scrollview (tableview) content size height + image view size height.
The heierarchy should look like this:
Then this scrollview on top that you have made with the really tall content size make its delegate be your view controller. Implement scrollViewDidScroll and we'll work some magic.
Scrollviews basically scroll by adjusting the bounds origin with funky formulas for momentum and stuff. So in our scrollviewDidScroll method we will simply adjust the bounds of the underlying views:
-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
//the scroll view underneath (in the container view) will have a max content offset equal to the content height
//but minus the bounds height
CGFloat maxYOffsetForUnderScrollView = self.underScrollView.contentSize.height - self.underScrollView.bounds.size.height;
CGRect scrolledBoundsForContainerView = self.view.bounds;
if (scrollView.contentOffset.y <= maxYOffsetForUnderScrollView) {
//in this scenario we are still within the content for the underScrollView
//so we make sure the container view is scrolled to the top and set the offset for the contained scrollview
self.containerView.bounds = scrolledBoundsForContainerView;
self.underScrollview.contentOffset = scrollView.contentOffset;
return;
}
//in this scenario we have scrolled throug the entirety of the contained scrollview
//set its offset to the max and change the bounds of the container view to scroll everything else.
self.underScrollView.contentOffset = CGPointMake(0, maxYOffsetForUnderScrollView);
scrolledBoundsForContainerView.origin.y = scrollView.contentOffset.y - maxYOffsetForUnderScrollView;
self.containerView.bounds = scrolledBoundsForContainerView;
}
You will find that as scrollViewDidScroll is called every frame of animation that this faux scrolling of the contained views looks really natural.
But wait! I hear you say. That scroll view on top now intercepts ALL touches, and the views underneath it need to be touched as well. I have an interesting solution for that as well.
Set the scrollview on top to be off screen somewhere (i.e. set its frame off screen, but still the same size.) and then in your viewDidLoad method you add the scrollview's panGestureRecogniser to the main view. This will mean that you get all the iOS natural scrolling momentum and stuff without actually having the view on the screen. The contained scroll view will now probably go juddery as its pan gesture recognizer will get called as well (they work differently to UIEvent handling) so you will need to remove it.
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
[self.view addGestureRecognizer:self.scrollview.panGestureRecognizer];
[self.underScrollview removeGestureRecognizer:self.underScrollView.panGestureRecognizer];
//further code to set up content sizes and stuff
}
I had fun making this so heres a link to the sample project on github:
https://github.com/joelparsons/multipleScrollers
EDIT:
To show the scrollbar for the top scrollview when its off the screen no matter where you put it you can set the scrollIndicatorInsets to an inset created like this:
CGPoint scrollviewOrigin = self.scrollview.frame.origin;
self.scrollview.scrollIndicatorInsets = UIEdgeInsetsMake(-scrollviewOrigin.y,0,scrollviewOrigin.y,scrollviewOrigin.x);
*caveat that the scrollview still has to be the right height but I'm sure you get the idea.
And then to make the bar draw outside the scrollview's visible bounds you have to turn off clips to bounds
self.scrollview.clipsToBounds = NO;
OMG. jackslash, you saved my life.
In my case, I need to use three depth of scroll views.
Parent Scroll View
that has a scroll view as one of the children
Child Scroll View: shown as 'Explanation Scroll View / Review Table View / Information Scroll View' in the below image)
Hidden Scroll View
which is distribute own content offset to 'Parent Scroll View' and 'Child Scroll View'
which has content size of whole flatten contents
Screenshot of view hierarchy
After setting view hierarchy, I just need to sync whole flatten content size and distribute content offset properly.
Observable.combineLatest(
overviewStackView.rx.observe(CGRect.self, #keyPath(UIStackView.frame)).unwrap(),
explanationScrollView.rx.observe(CGSize.self, #keyPath(UIScrollView.contentSize)).unwrap()
)
.subscribe(onNext: { [weak self] overviewStackViewFrame, explanationScrollViewContentSize in
guard let self = self else { return }
let totalContentHeight = overviewStackViewFrame.height + self.segmentedControl.frame.height + explanationScrollViewContentSize.height
self.hiddenScrollView.contentSize.height = totalContentHeight
})
.disposed(by: disposeBag)
hiddenScrollView.rx.didScroll
.subscribe(onNext: { [weak self] _ in
guard let self = self else { return }
let currentHiddenScrollViewOffsetY = self.hiddenScrollView.contentOffset.y
let parentScrollViewMaxOffsetY = self.overviewStackView.frame.height
let expectedChildScrollViewOffsetY = max(currentHiddenScrollViewOffsetY - parentScrollViewMaxOffsetY, 0)
self.parentScrollView.contentOffset.y = min(parentScrollViewMaxOffsetY, currentHiddenScrollViewOffsetY)
self.explanationScrollView.contentOffset.y = expectedChildScrollViewOffsetY
})
.disposed(by: disposeBag)
I can't figure out how to actually use NSScrollview. I dragged the scroll view object onto an NSWindow in the interface builder. I then dragged some NSButtons onto the scroll view. My question is:
How do I actually make it scroll down, for example, 2x the original height?
Of course the user can scroll automatically using their UI. I assume what you want to do is to scroll programmatically.
A bit of background: An NSScrollView has a documentView, which is the underlying view that the scroll view shows a part of, and a clipView, which is the view that is shown on the screen. So the clip view is like a window into the document view. To scroll programmatically you tell the document view to scroll itself in the clip view.
You have two options on how to scroll programmatically:
- (void)scrollPoint:(NSPoint)aPoint –– This scrolls the document so the given point is at the origin of the clip view that encloses it.
- (BOOL)scrollRectToVisible:(NSRect)aRect –– This scrolls the document the minimum distance so the entire rectangle is visible. Note: This may not need to scroll at all in which case it returns NO.
So, for example, here is an example from Apple's Scroll View Programming Guide on how to scroll to the bottom of the document view. Assuming you have an IBOutlet called scrollView connected up to the NSScrollView in your nib file you can do the following:
- (void)scrollToBottom
{
NSPoint newScrollOrigin;
if ([[scrollview documentView] isFlipped]) {
newScrollOrigin = NSMakePoint(0.0,NSMaxY([[scrollview documentView] frame])
-NSHeight([[scrollview contentView] bounds]));
} else {
newScrollOrigin = NSMakePoint(0.0,0.0);
}
[[scrollview documentView] scrollPoint:newScrollOrigin];
}
The view system in my app is highly customized and uses a number of views that are manually rotated from portrait to landscape based on user interactions (the rotation is done by applying an affine transform to the view/layer).
I want to present a popover inside one of these rotated views, but the orientation of the popover always appears relative to the orientation of the device (i.e., not relative to the view). I'm guessing the answer is no, but just in case someone has a clever idea: is there any way to manually rotate the view that is presented by UIPopoverController?
Sean, I just tested it for kicks, yes it works.
It has to be done (in my case at least) in viewDidAppear (if done in viewWillAppear, it gets knocked back to the original setting.)
This worked just fine (just tested now) to have a popover at a 90 degree angle. i.e in my case my main view is in portrait mode and the popover is turned 90 deg.
self.navigationController.view.superview.superview.transform = CGAffineTransformMakeRotation (M_PI/2.0);
Are you trying to rotate the popover or just the content shown in the popover? You can control some of the former by setting which arrow orientations are possible. I'm interested in the latter, and it seems to work just by grabbing the content view controller. E.g.:
aPopoverController.contentViewController.view.transform = CGAffineTransformMakeRotation(M_PI);
DISCLAIMER: If you're at all interested in trying to get your app into the store, this code is almost certainly grounds for rejection. It dives into UIKit's private API's which is a big no-no as far as apple is concerned.
#RunningPink had the right idea. Depending on how the view hierarchy is set up, the popover may be back up farther than two superviews. The popover itself it an instance of the (private) class _UIPopover (at least in iOS 5). You can find this view by doing:
UIView *possiblePopover = popoverController.contentViewController.view;
while (possiblePopover != nil) {
// Climb up the view hierarchy
possiblePopover = possiblePopover.superview;
if ( [NSStringFromClass([possiblePopover class]) isEqualToString:#"_UIPopoverView"] ) {
// We found the popover, break out of the loop
break;
}
}
if (nil != possiblePopover) {
// Do whatever you want with the popover
}
In doing this, I found that transforming the view often ended up making the popover look blurry. I found the reason was that the popover's superview was an instance of another private class called UIDimmingView which is responsible for accepting touches outside of the popover and causing the popover to dismiss. Performing the rotation on the dimming view removed the blurriness I was seeing in the popover.
However, transforming the dimming can result in weirdness where certain parts of the window are not "covered" by the dimming view so the popover will not dismiss if these parts of the window are tapped. To get around this, I applied the rotation to the dimming view, reset the dimming view's frame to cover the screen, and then translated the popover view into place.
if (nil != possiblePopover) {
// Found the popover view
CGAffineTransform rotation = CGAffineTransformMakeRotation(-M_PI_2);
CGAffineTransform translation = // Whatever translation in necessary here
// Rotate the UIDimming View and reset its frame
[possiblePopover.superview setTransform:rotation];
[possiblePopover.superview setFrame:CGRectMake(0, 0, possiblePopover.superview.frame.size.height, possiblePopover.superview.frame.size.width)];
// Translate the popover view
[possiblePopover setTransform:translation];
}
I have a UIScrollView whose content size is 1200x480. I have some image views on it, whose width adds up to 600. When scrolling towards the right, I simply increase the content size and set the offset so as to make everything smooth (I then want to add other images, but that's not important right now). So basically, the images currently in the viewport remain somewhere on the left, eventually to be removed from the superview.
Now, the problem that I have happens when scrolling towards the left. What I do is I move the images to the end of the content size (so add 600 to each image view's origin.x), and then set the content offset accordingly. It works when the finger is on the screen and the user drags (scrollView.isTracking = YES). When the user scrolls towards the left and lets go (scrollView.isTracking = NO), the image views end up moving too fast towards the right and disappear almost instantly. Does anyone know how I could have the images move nicely and not disappear even when the user's not manually dragging the view and has already let go?
Here's my code for dragging horizontally:
-(void) scrollViewDidScroll:(UIScrollView *)scrollView {
CGPoint offset = self.scrollView.contentOffset;
CGSize size = self.scrollView.contentSize;
CGPoint newXY = CGPointMake(size.width-600, size.height-480);
// this bit here allows scrolling towards the right
if (offset.x > size.width - 320) {
[self.scrollView setContentSize:CGSizeMake(size.width+320, size.height)];
[self.scrollView setContentOffset: offset];
}
// and this is where my problem is:
if (offset.x < 0) {
for (UIImageView *imageView in self.scrollView.subviews) {
CGRect frame = imageView.frame;
[imageView setFrame:CGRectMake
(frame.origin.x+newXY.x, frame.origin.y, 200, frame.size.height)];
}
[self.scrollView setContentOffset:CGPointMake(newXY.x+offset.x, offset.y)];
}
}
EDIT: This is now working - I had a look at StreetScroller and it's all good now.
However, I now want to zoom in on the scrollview, but viewForZoomingInScrollView is never called. Is it not possible to zoom in on a scrollview with a large content size?
There are some approaches floating around here. Just use the site search …
If you want an more "official" example created by Apple take a look at the StreetScroller Demo. For some more information about this example take a look at last years WWDC session no. 104 Advanced Scroll View Techniques.
There is also an UIScrollView subclass on Github called BAGPagingScrollView, which is paging & infinite, but it has a few bugs you have to fix on your own, because it's not under active development (especially the goToPage: method leads to problems).