How-To forward pan gesture from a scrollview to another scrollview - ios

I have two UIScrollViews and i want to let the other scrollview scroll too if the user scrolls in a scrollview. I have read a solution that involves passing the pangesturerecognizer from the originally panned scrollview to the other scrollview but if i do that the original scrollview does not scroll at all.
I found out, that there is a delegate method
(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
but if I try to hook up the delegate of the pangesturerecognizers of the scrollviews my app crashes.
Hope someone can help me.

You Just need to update the Bounds of the second ScrollView
Something like :-
CGRect updateTheViewWithBounds = viewToUpdate.bounds;
updateTheViewWithBounds.origin = scrolledView.contentOffset;
viewToUpdate.bounds = updateTheViewWithBounds;
This Will do the Job.
As Seen from comments , I will give a small Example.
Create the two scrollView onto The UiViewController
scrollOne = [[UIScrollView alloc] init];
[scrollOne setBackgroundColor:[UIColor greenColor]];
[scrollOne setFrame:CGRectMake(10, 20, 200, 300)];
[scrollOne setContentSize:CGSizeMake(600, 600)];
scrollOne.delegate = self;
scrollTwo = [[UIScrollView alloc] init];
[scrollTwo setBackgroundColor:[UIColor redColor]];
[scrollTwo setFrame:CGRectMake(230, 20, 200, 300)];
[scrollTwo setContentSize:CGSizeMake(600, 600)];
scrollTwo.delegate = self;
[self.view addSubview:scrollOne];
[self.view addSubview:scrollTwo];
Conform to the UIScrollView Delegates and implement the same.
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
if([scrollView isEqual:scrollOne])
{
CGRect updateTheViewWithBounds = scrollOne.bounds;
updateTheViewWithBounds.origin = scrollOne.contentOffset;
scrollTwo.bounds = updateTheViewWithBounds;
[scrollTwo flashScrollIndicators];
}
else if([scrollView isEqual:scrollTwo])
{
CGRect updateTheViewWithBounds = scrollTwo.bounds;
updateTheViewWithBounds.origin = scrollTwo.contentOffset;
scrollOne.bounds = updateTheViewWithBounds;
[scrollOne flashScrollIndicators];
}
}
Scrolling any of the above scrollView will scroll both the scrollView.

Related

Adding scrollview to a view

I have tried Adding UIScrollView to a UIViewController, and I can never get my view to move down when I scroll, either on a simulator on a real device. I have also tried increasing the size, so my code is as follows:
+(void)addScrollViewToView:(UIView *)view
{
UIScrollView* scrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, view.bounds.size.width * 2, view.bounds.size.height * 2)];
scrollView.backgroundColor = [UIColor clearColor];
scrollView.scrollEnabled = YES;
scrollView.pagingEnabled = YES;
scrollView.showsVerticalScrollIndicator = YES;
scrollView.showsHorizontalScrollIndicator = YES;
scrollView.contentSize = CGSizeMake(view.bounds.size.width * 2, view.bounds.size.height * 2);
[view insertSubview:scrollView atIndex:0];
//[view sendSubviewToBack:scrollView]; - commented out
}
It is called within viewDidLoad like so:
#implementation MyLoginViewController
- (void)viewDidLoad
{
[super viewDidLoad];
[Utils addScrollViewToView:self.view];
self.passwordTextField.secureTextEntry = YES;
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc]
initWithTarget:self
action:#selector(dismissKeyboard)];
[self.view addGestureRecognizer:tap];
} // viewDidLoad method ends here
There is never any response when I try and scroll up with my mouse on a simulator. There is a background image to my view controller that I created using a storyboard. Would changing the index make any difference?
It happen because you add gesture recognizer. Gesture recognizer blocks and not pass your touch.
You can make this for dismiss keyboard with UIScrollView:
+(void)addScrollViewToView:(UIView *)view
{
// your code
scrollView.keyboardDismissMode = UIScrollViewKeyboardDismissModeOnDrag;
}
And remove UITapGestureRecognizer.
Or is it because your frame size is the same as your content size? The scroll view will only scroll if its content is bigger than its frame.
What did the trick was adding the view to the scrollview.
I.e.:
View >
ScrollView >
View that I wanted to scroll
Not:
View that I wanted to scroll >
ScrollView.

Can I put a UIScrollView inside another UIScrollView

I have a UIScrollView which scrolls only in vertical direction, I need to place UIScrollView which can move horizontally, like the AppStore application in apple devices. I don't want to us UICollectionView since I have static data and I have to only 3 horizontal UIScrollView
Yes you can. As UIScrollView subclasses UIView it will behave as expected when adding subviews. Each scroll view will enable scrolling based on its contentSize property.
Objective-C:
UIScrollView *horizontalScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(40.0, 40.0, 300.0, 300.0)];
horizontalScrollView.backgroundColor = [UIColor lightGrayColor];
horizontalScrollView.contentSize = CGSizeMake(2000.0, 300.0);
[self.view addSubview:horizontalScrollView];
UIScrollView *verticalScrollView = [[UIScrollView alloc] initWithFrame:CGRectMake(40.0, 40.0, 220.0, 220.0)];
verticalScrollView.backgroundColor = [UIColor greenColor];
verticalScrollView.contentSize = CGSizeMake(220.0, 2000.0);
[horizontalScrollView addSubview:verticalScrollView];
Swift:
let horizontalScrollView = UIScrollView(frame: CGRectMake(40.0, 40.0, 300.0, 300.0))
horizontalScrollView.backgroundColor = UIColor.lightGrayColor()
horizontalScrollView.contentSize = CGSizeMake(2000.0, 300.0)
self.view.addSubview(horizontalScrollView)
let verticalScrollView = UIScrollView(frame: CGRectMake(40.0, 40.0, 220.0, 220.0))
verticalScrollView.backgroundColor = UIColor.greenColor()
verticalScrollView.contentSize = CGSizeMake(220.0, 2000.0)
horizontalScrollView.addSubview(verticalScrollView)
Yes you can. But you need to differentiate the scroll views in scroll view delegate methods. Either you can use tags or if you are declaring them as global variables in the entire class,you can directly access them with their names.Eg:
UIScrollView *parentScrollView = [[UIScrollView alloc] init];
parentScrollView.delegate = self;
[self.view addSubview:parentScrollView];
UIScrollView *childScrollView = [[UIScrollView alloc] init];
childScrollView.delegate = self;
[parentScrollView addSubview:childScrollView];
Now inside delegate method you can check for the scroll view like
if(scrollview == parentScrollview)
{
// do your actions
}
This is possible only if your scroll view objects are global to the class. You can also give a tag and check for the tag in scroll view delegate method like
parentScrollView. tag = 101;
And in scroll view delegate method
if(scrollview.tag = 101)
{
// do your actions
}
yes it is possible but you have to maintain tag of scrollview for handling delegate methods of scroll view.
UIScrollView has a property called scrollEnabled, which you can set to NO to disable scrolling in your parent scroll view.
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
if(scrollView == innerView)
outerView.scrollEnabled = NO;
else
outerView.scrollEnabled = YES;
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
if(scrollView == innerView)
{
if(innerView.contentOffset.x + innerView.frame.size.width == innerView.contentSize.width)
{
outerView.scrollEnabled = NO;
}
else
{
outerView.scrollEnabled = YES;
}
}
}
Or else you can go through the below link.

Scrolldown a TableView makes the UIImage background move up

Hi here is what I'm trying to do.
I've got a Table View with transparent cell's background.
cell.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"trans.png"]];
And I added to the ViewDidLoad a background image.
- (void)viewDidLoad {
bgView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 320, 480)];
bgView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"homelights.png"]];
[super viewDidLoad];
self.title = #"";
}
So this works fine, I've got a tableView with transparent cells and a background image. Now the plan is when I scroll the TableView down, the image should react and move up.
Any idea how to trigger the scrolldown? Or where to start?
I enabled scrollViewDidScroll;
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
CGFloat scrollOffset = scrollView.contentOffset.y;
Works like a charm, I can read the scroll position, but when I'm trying to animate UIView, by linking the scrollView.contentOffset.y to the UIView "y" position;
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
CGFloat scrollOffset = scrollView.contentOffset.y;
[UIView beginAnimations:#"UIViewAnimationCurveEaseInOut" context:nil];
bgView.center = CGPointMake(bgView.center.x, bgView.center.y+scrollOffset);
[UIView commitAnimations];
}
So I tried to make the UIView bigger to the original size of the image 640x832 to be able to navigate on it, but doesn't seems to work.
bgView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 640, 832)];
bgView.backgroundColor = [UIColor colorWithPatternImage:[UIImage imageNamed:#"homelights.png"]];
Any idea why this is happening?
Your table view is a subclass of UIScrollView and your delegate for the table view is also (automatically) a delegate of the scroll view. Implement the scrollViewDidScroll: delegate method and use it to monitor how the table view has changed and move your background view.

UIScrollView can zoom, but cant pan

I have a UIScrollView with a UIView inside it, in side the UIView I made a button to add textLabels to it.
and ideally I would want a really big canvas and be able to put text on it and pan and zoom around. however with the UIScrollView it does zoom, but does not pan at all
It seems that when I remove the UIView that i add inside the UIScrollView it works fine.
heres viewDidLoad:
[super viewDidLoad];
CGFloat mainViewWidth = 700;
CGFloat mainViewHeight = 500;
//scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * kNumberOfPages, scrollView.frame.size.height * kNumberOfPages);
//self.mainScrollView.bounds = CGRectMake(0., 0., 3000, 3000);
self.mainScrollView.scrollsToTop = NO;
self.mainScrollView.delegate = self;
self.mainScrollView.maximumZoomScale = 50.;
self.mainScrollView.minimumZoomScale = .1;
self.mainScrollView.autoresizingMask = UIViewAutoresizingFlexibleHeight;
self.mainView = [[UIView alloc] initWithFrame: CGRectMake(0, 0, mainViewWidth, mainViewHeight)];
[self.mainView setUserInteractionEnabled:NO];
self.mainView.backgroundColor = [[UIColor alloc] initWithRed:0.82110049709463495
green:1
blue:0.95704295882687884
alpha:1];
[self.mainScrollView setContentSize:CGSizeMake(5000, 5000)];
[self.mainScrollView insertSubview:self.mainView atIndex:0];
Edit:
Heres the all I have for UIScrollViewDelegate
#pragma mark - Scroll View Delegate
- (void)scrollViewDidScroll:(UIScrollView *)sender {
}
- (UIView *)viewForZoomingInScrollView:(UIScrollView *)scrollView
{
//
return self.mainView;
}
- (void)scrollViewDidEndZooming:(UIScrollView *)zoomedScrollView withView:(UIView *)view atScale:(float)scale
{
}
I just went through this exact same dilemma.
My UIScrollView exists within the storyboard, and if I add a UIView (containerView) within that storyboard to the UIScrollView, the image fails to pan. And all sorts of other centering weirdness occurs too.
But if I do it through code:
// Set up the image we want to scroll & zoom
UIImage *image = [UIImage imageNamed:#"plan-150ppi.jpg"];
self.imageView = [[UIImageView alloc] initWithImage:image];
self.containerView = [[UIView alloc] initWithFrame:self.imageView.frame];
[self.containerView addSubview:self.imageView];
[self.scrollView addSubview:self.containerView];
// Tell the scroll view the size of the contents
self.scrollView.contentSize = self.containerView.frame.size;
... then it works just fine.

UIScrollView with multiple subViews

I have a UIScrollView with many other subviews inside it. Most of the subviews are UITextView's and when they are all loaded, the scrolling and everything is fine. But for one of the views, I am loading a UIView with a MKMapView and a UITextView inside of it. When the user wants to scroll the UIScrollView, they cannot touch the UIView or its contents. I cannot set setUserInteractionEnabled to NO because I need the user to be able to click on the MKMapView and then go to another UIViewController for the map. Are there any suggestions regarding this? I have my code for the above below:
CGRect dealDescRect = CGRectMake(10, 10, delegate.scrollView.frame.size.width - 22 - 20, 120);
mapView = [[MKMapView alloc] initWithFrame:dealDescRect];
mapView.layer.cornerRadius = cornerRadius;
mapView.scrollEnabled = NO;
mapView.zoomEnabled = NO;
BOOL result = [self loadAddressIntoMap];
if (result == TRUE) {
UITapGestureRecognizer* recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTap:)];
[mapView addGestureRecognizer:recognizer];
}
UITextView *addressTextView = [self generateTextView:addressText :5];
addressTextView.editable = NO;
[addressTextView setFont:[UIFont systemFontOfSize:fontSize]];
[addressTextView setUserInteractionEnabled:NO];
CGRect addressTextViewFrame = addressTextView.frame;
addressTextViewFrame.origin.x = 0;
addressTextViewFrame.origin.y = 130;
addressTextViewFrame.size.height = addressTextView.contentSize.height + 15;
addressTextView.frame = addressTextViewFrame;
CGRect viewRect = CGRectMake(10, 145, delegate.scrollView.frame.size.width - 22, addressTextView.contentSize.height + 135);
viewRect.origin.x = 11;
viewRect.origin.y = startTop;
UIView *view = [[UIView alloc] initWithFrame:viewRect];
view.layer.cornerRadius = cornerRadius;
[view setBackgroundColor:[UIColor whiteColor]];
[view addSubview:mapView];
[view addSubview:addressTextView];
EDIT
For some weird reason, if I change the UIView to a UITextView, it works! Not sure what the real solution here is though. I just disable editing.
If it were me, instead of using gesture recognizers to watch for a tap on the map I'd create a UIButton of a custom type (UIButtonTypeCustom) and give it no background and no text, and place it on top of the map with the same frame as the map.
This has the benefit of preventing the user from interacting with the map, moving to the next page as you want and if the user starts scrolling even when over the map they are able to.

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