Related
I have a background subview which just have grey color's, and got tiles on top of it which can be dragged. This is all happening in one view controller. The problem is that when I do a hit test and try to avoid the backgroundView, since the tiles are on top of that view, it still see's those coordinates and avoid the touches move event since I am returning nil.
Below is the code:
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
for (UIView *view in self.subviews) {
//This checks if touches are within the region of the custom view based on its cordinates.
if (CGRectContainsPoint(view.frame, point)) {
NSLog(#"touched the boat view %f %f and %f %f",view.frame.origin.x, view.frame.origin.y, point.x, point.y);
if ([view isEqual:backgroundView]) {
return nil;
}
else
return view;
}
}
return nil;
}
If you can see I am verifying for the background view, but since my tiles are on of the background view, those are not being dragged based on my other logic. I have tried userInteractiveEnabled to No, but that doesn't seams to work. Any suggestions?
you should have a subclass of uiview and implement hitTest on this subclass :
#implementation EDPassTroughView
- (id)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
// Initialization code
}
return self;
}
-(UIView*)hitTest:(CGPoint)point withEvent:(UIEvent *)event{
UIView *hitView = [super hitTest:point withEvent:event];
if (hitView == self)
return nil;
else
return hitView;
}
#end
I have an application with three buttons (actually UIView's) laid out horizontally underneath the navigation bar.
The three buttons are of substantial enough size (larger than the back button, for example), however they won't respond to touches when the hit is in the top third part, roughly.
I'm aware that this area directly underneath the nav bar is sort of 'reserved' for the back button and other UINavigation items having a touch area that expands beyond the navigation bar (by quite a significant margin), however in some instance there isn't even a navigation item nearby to steal the event, and my views still don't respond.
The weird thing is that I am getting a call to the hitTest method in my UIView, just never a touchesBegan/Ended/etc.
The result is that it is very difficult to press the buttons and if one is anywhere near a UINavigationItem, the item will steal the event, even though in hitTest I am returning the correct UIView to the system.
Unfortunately I am the implementer and not the designer so a design change is a last resort.
Any ideas? Thanks!
You have to subclass your UINavigationBar and in your CustomNavigationBar do this:
-(UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if ([self pointInside:point withEvent:event]) {
self.userInteractionEnabled = YES;
} else {
self.userInteractionEnabled = NO;
}
return [super hitTest:point withEvent:event];
}
Info about how to subclass UINavigationBar you can find here.
The code provided by #Andrei will cause controller stack inconsistency on iOS 7 when quickly push and pop controllers. The system itself will change the userInteractionEnabled property before and after push/pop animations. Here is how I fixed this issue.
#interface DMNavigationBar ()
#property (nonatomic, assign) BOOL changingUserInteraction;
#property (nonatomic, assign) BOOL userInteractionChangedBySystem;
#end
#implementation DMNavigationBar
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
if (self.userInteractionChangedBySystem && self.userInteractionEnabled == NO)
{
return [super hitTest:point withEvent:event];
}
if ([self pointInside:point withEvent:event])
{
self.changingUserInteraction = YES;
self.userInteractionEnabled = YES;
self.changingUserInteraction = NO;
}
else
{
self.changingUserInteraction = YES;
self.userInteractionEnabled = NO;
self.changingUserInteraction = NO;
}
return [super hitTest:point withEvent:event];
}
- (void)setUserInteractionEnabled:(BOOL)userInteractionEnabled
{
if (!self.changingUserInteraction)
{
self.userInteractionChangedBySystem = YES;
}
else
{
self.userInteractionChangedBySystem = NO;
}
[super setUserInteractionEnabled:userInteractionEnabled];
}
#end
Had the same problem and the above answers are good and they point to a concise solution.
The same answer for the swift version:
class APLVNavigationBar: UINavigationBar {
override func hitTest(point: CGPoint, withEvent event: UIEvent?) -> UIView? {
if pointInside(point, withEvent: event){
userInteractionEnabled = true
}else{
userInteractionEnabled = false
}
return super.hitTest(point, withEvent: event)
}
}
I dont think that it is the problem, but did you bring the button subviews to the front?
[self.view bringSubviewToFront:buttonView]
I have UIViewControllerand UITableView as child in the view,
what I want to do is when I touch any row I am displaying a view at bottom. I want to hide that view if the user touch any where else then rows or the bottomView.
The problem is when I click on UITableView it doesn't fires touchesEnded event.
Now how can I detect touch on UITableView and distinguish it with row selection event.
Thanks.
No need to subclass anything, you can add a UITapGestureRecognizer to the UITableView and absorb the gesture or not depending on your criteria.
In your viewDidLoad:
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(didTapOnTableView:)];
[self.myTableView addGestureRecognizer:tap];
Then, implement your action like this for the criteria:
-(void) didTapOnTableView:(UIGestureRecognizer*) recognizer {
CGPoint tapLocation = [recognizer locationInView:self.myTableView];
NSIndexPath *indexPath = [self.myTableView indexPathForRowAtPoint:tapLocation];
if (indexPath) { //we are in a tableview cell, let the gesture be handled by the view
recognizer.cancelsTouchesInView = NO;
} else { // anywhere else, do what is needed for your case
[self.navigationController popViewControllerAnimated:YES];
}
}
And note that if you just want to simply pick up clicks anywhere on the table, but not on any buttons in cell rows, you need only use the first code fragment above. A typical example is when you have a UITableView and there is also a UISearchBar. You want to eliminate the search bar when the user clicks, scrolls, etc the table view. Code example...
-(void)viewDidLoad {
[super viewDidLoad];
etc ...
[self _prepareTable];
}
-(void)_prepareTable {
self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
self.tableView.allowsSelection = NO;
etc...
UITapGestureRecognizer *anyTouch =
[[UITapGestureRecognizer alloc]
initWithTarget:self action:#selector(tableTap)];
[self.tableView addGestureRecognizer:anyTouch];
}
// Always drop the keyboard when the user taps on the table:
// This will correctly NOT affect any buttons in cell rows:
-(void)tableTap {
[self.searchBar resignFirstResponder];
}
// You probably also want to drop the keyboard when the user is
// scrolling around looking at the table. If so:
-(void)scrollViewDidScroll:(UIScrollView *)scrollView {
[self.searchBar resignFirstResponder];
}
// Finally you may or may not want to drop the keyboard when
// a button in one cell row is clicked. If so:
-(void)clickedSomeCellButton... {
[self.searchBar resignFirstResponder];
...
}
Hope it helps someone.
You should forward the touch event to the view's controller.
Subclass your tableview control and then override the method:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesBegan:touches withEvent:event]; //let the tableview handle cell selection
[self.nextResponder touchesBegan:touches withEvent:event]; // give the controller a chance for handling touch events
}
then , you can do what you want in the controller's touch methods.
I just stumbled onto what may be a solution for your problem. Use this code when you create your table view:
tableView.canCancelContentTouches = NO;
Without setting this to NO, the touch events are cancelled as soon as there is even a slight bit of vertical movement in your table view (if you put NSLog statements in your code, you'll see that touchesCancelled is called as soon as the table starts scrolling vertically).
I was facing the problem since a long time and didn't got any working solution. Finally I choose to go with a alternative. I know technically this is not the solution but this may help someone looking for the same for sure.
In my case I want to select a row that will show some option after that I touch anywhere on table or View I want to hide those options or do any task except the row selected previously for that I did following:
Set touch events for the view. This will do the task when you touch anywhere on the view except the table view.
TableView's didSelectRowAtIndexPath do following
- (void)tableView:(UITableView*)tableView didSelectRowAtIndexPath:(NSIndexPath*)indexPath {
if(indexPath.row != previousSelectedRow && previousSelectedRow != -1) {
// hide options or whatever you want to do
previousSelectedRow = -1;
}
else {
// show your options or other things
previousSelectedRow = indexPath.row;
}
}
I know that this is older post and not a good technical solution but this worked for me. I am posting this answer because this may help someone for sure.
Note: The code written here may have spell mistakes because directly typed here. :)
Try this methods:
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
}
Use scrollViewDidEndDragging like alternative of touchesEnded. Hope it helps.
To receive touch events on the UITableView use:
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//<my stuff>
[super touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
//<my stuff>
[super touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event
{
//<my stuff>
[super touchesEnded:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet*)touches withEvent:(UIEvent*)event
{
//<my stuff>
[super touchesCancelled:touches withEvent:event];
}
In your controller class declare a method which removes the bottom view. Something like this:
-(IBAction)bottomViewRemove:(id)sender {
[bottomView removeFromSuperview];
}
In Interface Builder, select your view and in the identity inspector in the custom class section, change the class from UIView to UIControl. After that go to the connections inspector and connect the TouchUpInside event to the method declared above. Hope this helps.
I have created a subclass of UIWebView , and have implemented the
touchesBegan, touchesMoved and touchesEnded methods.
but the webview subclass is not handling the touch events.
Is there any method to handle the touch events inside the UIWebView subclass ???
No subclassing needed, just add a UITapGestureRecognizer :
UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(didTapMethod)];
[tap setNumberOfTapsRequired:1]; // Set your own number here
[tap setDelegate:self]; // Add the <UIGestureRecognizerDelegate> protocol
[self.myWebView addGestureRecognizer:tap];
Add the <UIGestureRecognizerDelegate> protocol in the header file, and add this method:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
If all you need is to handle gestures, while leaving the rest of the UIWebView functionality intact, you can subclass UIWebView and use this strategy:
in the init method of your UIWebView subclass, add a gesture recognizer, e.g.:
UISwipeGestureRecognizer * swipeRight = [[UISwipeGestureRecognizer alloc]initWithTarget:self action:#selector(handleSwipeGestureRightMethod)];
swipeRight.direction = UISwipeGestureRecognizerDirectionRight;
[self addGestureRecognizer:swipeRight];
swipeRight.delegate = self;
then, add this method to your class:
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
return YES;
}
Add and handle your designated selector to the class, in this case "handleSwipeGestureRightMethod" and you are good to go...
You could put an UIView over your UIWebView, and overide the touchesDidBegin etc, then send them to your webview. Ex:
User touches your UIView, which provokes a
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
// Execute your code then send a touchesBegan to your webview like so:
[webView touchesBegan:touches withEvent:event];
return;
}
your UIView has to be over the webview.
I'm not sure if this is what you want (it's not what you asked for, but it might work depending on what your end game is), but you could instead interpret the touches in JavaScript from inside the UIWebView, and get javascript to do
document.location='http://null/'+xCoord+'/'+yCoord; // Null is arbitrary.
Then you can catch that using the UIWebView's delegate method
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
And if the request.URL.host (or whatever it is) isEqualToString:#"null" take the relevant action (and return NO instead of YES). You can even add the JS to each page by doing something like:
- (void)webViewDidFinishLoad:(UIWebView *)webView {
[webView stringByEvaluatingJavaScriptFromString:#"window.ontouchstart=function(/* ... */);"];
}
Hope this helps?
Handling gestures on a UIWebView is discussed in this Apple Developer forum thread.
Using the info given there, there will be no need for an extra view in most or all cases, and as mentioned here before, overriding UIWebView is not the way to go.
Copypaste of the most important post in the thread:
This is a known issue. The UIWebView has its own UITapGestureRecognizers, and they're on a private subview of the UIWebView itself. UIGestureRecognizer precedence defines that gestures attached to views deeper in the view hierarchy will exclude ones on superviews, so the web view's tap gestures will always win over yours.
If it's okay in your case to allow your tap to happen along with the web view's normal tap your best solution would be to implement the UIGestureRecognizerDelegate method gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer and return YES for other tap gestures. This way you'll get your tap handler called, and the web view will still get its called.
If you need to be the only one handling the tap you'll have to subclass UITapGestureRecognizer so you can use the one-way overrides in UIGestureRecognizerSubclass.h, an you can then return NO from canBePreventedByGestureRecognizer: when asked if the web view's tap gesture recognizer can prevent yours.
In any case, we know about this and hope to make it easier in the future.
I've just found that UIWebView does check whether it responds to the - (void)webViewDidNotClick: (id)webBrowserView selector, once one taps on the view area (not on hyperref, or any other area that should be handled specifically). So you may implement that selector with your handling code :)
Do you mean your sub-classed implementation is not called when touchesBegan, touchesMoved and touchesEnded are called?
It sounds like a problem with how you've created an instance of the object. More details are required I think.
(taken form comments)
Header File
#import <UIKit/UIKit.h>
#interface MyWebView : UIWebView { } #end
Implementation File
#import "MyWebView.h"
#implementation MyWebView
- (id)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) { } return self;
}
- (void)drawRect:(CGRect)rect {
NSLog(#"MyWebView is loaded");
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"touches began");
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"Touches ended");
}
- (void)dealloc {
[super dealloc];
}
#end
I would try overriding -sendEvent: on UIWindow, to see if you can intercept those touch events.
Following on from what Unfalkster said, you can use the hitTest method to achieve what you want, but you don't have to subclass UIWindow. Just put this in your web view subclass. You will get a compile time warning but it does work:
- (void)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
if (event.type == UIEventTypeTouches) {
// get location info
CGFloat x = point.x;
CGFloat y = point.y;
// get touches
NSSet *touches = [event allTouches];
// individual touches
for (UITouch *touch in touches) {
if (touch.phase == UITouchPhaseBegan) {
// touches began
} else if (touch.phase == UITouchPhaseMoved) {
}
// etc etc
}
}
// call the super
[super hitTest:point withEvent:event];
}
Hope that helps!
If you want to detect your own taps but disable the UIWebView's taps then you can use my solution:
-(void)recursivelyDisableTapsOnView:(UIView*)v{
for(UIView* view in v.subviews){
for(UIGestureRecognizer* g in view.gestureRecognizers){
if(g == self.ownTapRecognizer){
continue;
}
if([g isKindOfClass:[UITapGestureRecognizer class]] ||
[g isKindOfClass:[UILongPressGestureRecognizer class]] ||
[g isKindOfClass:NSClassFromString(#"UITapAndAHalfRecognizer")]){
g.enabled = NO;
}
}
[self recursivelyDisableTapsOnView:view];
}
}
- (void)webViewDidFinishLoad:(UIWebView *)webView{
[self recursivelyDisableTapsOnView:webView];
//disable selection
[webView stringByEvaluatingJavaScriptFromString:#"document.documentElement.style.webkitUserSelect='none';"];
// Disable callout
[webView stringByEvaluatingJavaScriptFromString:#"document.documentElement.style.webkitTouchCallout='none';"];
}
I have an app where my main view accepts both touchesBegan and touchesMoved, and therefore takes in single finger touches, and drags. I want to implement a UIScrollView, and I have it working, but it overrides the drags, and therefore my contentView never receives them. I'd like to implement a UIScrollview, where a two finger drag indicates a scroll, and a one finger drag event gets passed to my content view, so it performs normally. Do I need create my own subclass of UIScrollView?
Here's my code from my appDelegate where I implement the UIScrollView.
#implementation MusicGridAppDelegate
#synthesize window;
#synthesize viewController;
#synthesize scrollView;
- (void)applicationDidFinishLaunching:(UIApplication *)application {
// Override point for customization after app launch
//[application setStatusBarHidden:YES animated:NO];
//[window addSubview:viewController.view];
scrollView.contentSize = CGSizeMake(720, 480);
scrollView.showsHorizontalScrollIndicator = YES;
scrollView.showsVerticalScrollIndicator = YES;
scrollView.delegate = self;
[scrollView addSubview:viewController.view];
[window makeKeyAndVisible];
}
- (void)dealloc {
[viewController release];
[scrollView release];
[window release];
[super dealloc];
}
In SDK 3.2 the touch handling for UIScrollView is handled using Gesture Recognizers.
If you want to do two-finger panning instead of the default one-finger panning, you can use the following code:
for (UIGestureRecognizer *gestureRecognizer in scrollView.gestureRecognizers) {
if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]]) {
UIPanGestureRecognizer *panGR = (UIPanGestureRecognizer *) gestureRecognizer;
panGR.minimumNumberOfTouches = 2;
}
}
For iOS 5+, setting this property has the same effect as the answer by Mike Laurence:
self.scrollView.panGestureRecognizer.minimumNumberOfTouches = 2;
One finger dragging is ignored by panGestureRecognizer and so the one finger drag event gets passed to the content view.
In iOS 3.2+ you can now achieve two-finger scrolling quite easily. Just add a pan gesture recognizer to the scroll view and set its maximumNumberOfTouches to 1. It will claim all single-finger scrolls, but allow 2+ finger scrolls to pass up the chain to the scroll view's built-in pan gesture recognizer (and thus allow normal scrolling behavior).
UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(recognizePan:)];
panGestureRecognizer.maximumNumberOfTouches = 1;
[scrollView addGestureRecognizer:panGestureRecognizer];
[panGestureRecognizer release];
You need to subclass UIScrollView (of course!). Then you need to:
make single-finger events to go to your content view (easy), and
make two-finger events scroll the scroll view (may be easy, may be hard, may be impossible).
Patrick's suggestion is generally fine: let your UIScrollView subclass know about your content view, then in touch event handlers check the number of fingers and forward the event accordingly. Just be sure that (1) the events you send to content view don't bubble back to UIScrollView through the responder chain (i.e. make sure to handle them all), (2) respect the usual flow of touch events (i.e. touchesBegan, than some number of {touchesBegan, touchesMoved, touchesEnded}, finished with touchesEnded or touchesCancelled), especially when dealing with UIScrollView. #2 can be tricky.
If you decide the event is for UIScrollView, another trick is to make UIScrollView believe your two-finger gesture is actually a one-finger gesture (because UIScrollView cannot be scrolled with two fingers). Try passing only the data for one finger to super (by filtering the (NSSet *)touches argument — note that it only contains the changed touches — and ignoring events for the wrong finger altogether).
If that does not work, you are in trouble. Theoretically you can try to create artificial touches to feed to UIScrollView by creating a class that looks similar to UITouch. Underlying C code does not check types, so maybe casting (YourTouch *) into (UITouch *) will work, and you will be able to trick UIScrollView into handling the touches that did not really happen.
You probably want to read my article on advanced UIScrollView tricks (and see some totally unrelated UIScrollView sample code there).
Of course, if you can't get it to work, there's always an option of either controlling UIScrollView's movement manually, or use an entirely custom-written scroll view. There's TTScrollView class in Three20 library; it does not feel good to the user, but does feel good to programmer.
This answers are a mess since you can only find the correct answer by reading all the other answers and the comments (closest answer got the question backwards). The accepted answer is too vague to be useful, and suggests a different method.
Synthesizing, this works
// makes it so that only two finger scrolls go
for (id gestureRecognizer in self.gestureRecognizers) {
if ([gestureRecognizer isKindOfClass:[UIPanGestureRecognizer class]])
{
UIPanGestureRecognizer *panGR = gestureRecognizer;
panGR.minimumNumberOfTouches = 2;
panGR.maximumNumberOfTouches = 2;
}
}
This requires two fingers for a scroll. I've done this in a subclass, but if not, just replace self.gestureRecognizers with myScrollView.gestureRecognizers and you're good to go.
The only thing that I added is using id to avoid an ugly cast :)
This works but can get quite messy if you want your UIScrollView to do zoom too... the gestures don't work correctly, since pinch-to-zoom and scroll fight it out. I'll update this if I find a suitable answer.
we managed to implement similar functionality in our iPhone drawing app by subclassing UIScrollView and filtering events depending on number of touches in simple and rude way:
//OCRScroller.h
#interface OCRUIScrollView: UIScrollView
{
double pass2scroller;
}
#end
//OCRScroller.mm
#implementation OCRUIScrollView
- (id)initWithFrame:(CGRect)aRect {
pass2scroller = 0;
UIScrollView* newv = [super initWithFrame:aRect];
return newv;
}
- (void)setupPassOnEvent:(UIEvent *)event {
int touch_cnt = [[event allTouches] count];
if(touch_cnt<=1){
pass2scroller = 0;
}else{
double timems = double(CACurrentMediaTime()*1000);
pass2scroller = timems+200;
}
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[self setupPassOnEvent:event];
[super touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[self setupPassOnEvent:event];
[super touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
pass2scroller = 0;
[super touchesEnded:touches withEvent:event];
}
- (BOOL)touchesShouldBegin:(NSSet *)touches withEvent:(UIEvent *)event inContentView:(UIView *)view
{
return YES;
}
- (BOOL)touchesShouldCancelInContentView:(UIView *)view
{
double timems = double(CACurrentMediaTime()*1000);
if (pass2scroller == 0 || timems> pass2scroller){
return NO;
}
return YES;
}
#end
ScrollView setuped as follows:
scroll_view = [[OCRUIScrollView alloc] initWithFrame:rect];
scroll_view.contentSize = img_size;
scroll_view.contentOffset = CGPointMake(0,0);
scroll_view.canCancelContentTouches = YES;
scroll_view.delaysContentTouches = NO;
scroll_view.scrollEnabled = YES;
scroll_view.bounces = NO;
scroll_view.bouncesZoom = YES;
scroll_view.maximumZoomScale = 10.0f;
scroll_view.minimumZoomScale = 0.1f;
scroll_view.delegate = self;
self.view = scroll_view;
simple tap does nothing (you can handle it in the way you need), tap with two fingers scrolls/zooms view as expected. no GestureRecognizer is used, so works from iOS 3.1
I've got a further improvement to the code above. The problem was, that even after we set setCanCancelContentTouches:NO We have the problem, that a zoom gesture will interrupt with the content. It won't cancel the content touch but allow zooming in the meantime. TO prevent this i lock the zooming by setting the minimumZoomScale and maximumZoomScale to the same values everytime, the timer fires.
A quite strange behavior is that when a one finger event gets canceled by a two finger gesture within the allowed time period, the timer will be delayed. It gets fired after the touchCanceled Event gets called. So we have the problem, that we try to lock the zooming although the event is already canceled and therefore disable zooming for the next event.
To handle this behavior the timer callback method checks against if touchesCanceled was called before.
#implementation JWTwoFingerScrollView
#pragma mark -
#pragma mark Event Passing
- (id)initWithCoder:(NSCoder *)coder {
self = [super initWithCoder:coder];
if (self) {
for (UIGestureRecognizer* r in self.gestureRecognizers) {
if ([r isKindOfClass:[UIPanGestureRecognizer class]]) {
[((UIPanGestureRecognizer*)r) setMaximumNumberOfTouches:2];
[((UIPanGestureRecognizer*)r) setMinimumNumberOfTouches:2];
zoomScale[0] = -1.0;
zoomScale[1] = -1.0;
}
timerWasDelayed = NO;
}
}
return self;
}
-(void)lockZoomScale {
zoomScale[0] = self.minimumZoomScale;
zoomScale[1] = self.maximumZoomScale;
[self setMinimumZoomScale:self.zoomScale];
[self setMaximumZoomScale:self.zoomScale];
NSLog(#"locked %.2f %.2f",self.minimumZoomScale,self.maximumZoomScale);
}
-(void)unlockZoomScale {
if (zoomScale[0] != -1 && zoomScale[1] != -1) {
[self setMinimumZoomScale:zoomScale[0]];
[self setMaximumZoomScale:zoomScale[1]];
zoomScale[0] = -1.0;
zoomScale[1] = -1.0;
NSLog(#"unlocked %.2f %.2f",self.minimumZoomScale,self.maximumZoomScale);
}
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"began %i",[event allTouches].count);
[self setCanCancelContentTouches:YES];
if ([event allTouches].count == 1){
touchesBeganTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(firstTouchTimerFired:) userInfo:nil repeats:NO];
[touchesBeganTimer retain];
[touchFilter touchesBegan:touches withEvent:event];
}
}
//if one finger touch gets canceled by two finger touch, this timer gets delayed
// so we can! use this method to disable zooming, because it doesnt get called when two finger touch events are wanted; otherwise we would disable zooming while zooming
-(void)firstTouchTimerFired:(NSTimer*)timer {
NSLog(#"fired");
[self setCanCancelContentTouches:NO];
//if already locked: unlock
//this happens because two finger gesture delays timer until touch event finishes.. then we dont want to lock!
if (timerWasDelayed) {
[self unlockZoomScale];
}
else {
[self lockZoomScale];
}
timerWasDelayed = NO;
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
// NSLog(#"moved %i",[event allTouches].count);
[touchFilter touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"ended %i",[event allTouches].count);
[touchFilter touchesEnded:touches withEvent:event];
[self unlockZoomScale];
}
//[self setCanCancelContentTouches:NO];
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#"canceled %i",[event allTouches].count);
[touchFilter touchesCancelled:touches withEvent:event];
[self unlockZoomScale];
timerWasDelayed = YES;
}
#end
Bad news: iPhone SDK 3.0 and up, don't pass touches to -touchesBegan: and -touchesEnded: **UIScrollview**subclass methods anymore. You can use the touchesShouldBegin and touchesShouldCancelInContentView methods that is not the same.
If you really want to get this touches, have one hack that allow this.
In your subclass of UIScrollView override the hitTest method like this:
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
UIView *result = nil;
for (UIView *child in self.subviews)
if ([child pointInside:point withEvent:event])
if ((result = [child hitTest:point withEvent:event]) != nil)
break;
return result;
}
This will pass to you subclass this touches, however you can't cancel the touches to UIScrollView super class.
What I do is have my view controller set up the scroll view:
[scrollView setCanCancelContentTouches:NO];
[scrollView setDelaysContentTouches:NO];
And in my child view I have a timer because two-finger touches usually start out as one finger followed quickly by two fingers.:
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
// Hand tool or two or more touches means a pan or zoom gesture.
if ((selectedTool == kHandToolIndex) || (event.allTouches.count > 1)) {
[[self parentScrollView] setCanCancelContentTouches:YES];
[firstTouchTimer invalidate];
firstTouchTimer = nil;
return;
}
// Use a timer to delay first touch because two-finger touches usually start with one touch followed by a second touch.
[[self parentScrollView] setCanCancelContentTouches:NO];
anchorPoint = [[touches anyObject] locationInView:self];
firstTouchTimer = [NSTimer scheduledTimerWithTimeInterval:kFirstTouchTimeInterval target:self selector:#selector(firstTouchTimerFired:) userInfo:nil repeats:NO];
firstTouchTimeStamp = event.timestamp;
}
If a second touchesBegan: event comes in with more than one finger, the scroll view is allowed to cancel touches. So if the user pans using two fingers, this view would get a touchesCanceled: message.
This seems to be the best resource for this question on the internet. Another close solution can be found here.
I have solved this issue in a very satisfactory manner in a different way, essentially by supplanting my own gesture recognizer into the equation. I strongly recommend that anyone who is trying to achieve the effect requested by the original poster consider this alternative over aggressive subclassing of UIScrollView.
The following process will provide:
A UIScrollView containing your custom view
Zoom and Pan with two fingers (via UIPinchGestureRecognizer)
Your view's event processing for all other touches
First, let's assume you have a view controller and its view. In IB, make the view a subview of a scrollView and adjust the resize rules of your view so that it does not resize. In the attributes of the scrollview, turn on anything that says "bounce" and turn off "delaysContentTouches". Also you must set the zoom min and max to other than the default of 1.0 for, as Apple's docs say, this is required for zooming to work.
Create a custom subclass of UIScrollView, and make this scrollview that custom subclass. Add an outlet to your view controller for the scrollview and connect them up. You're now totally configured.
You will need to add the following code to the UIScrollView subclass so that it transparently passes touch events (I suspect this could be done more elegantly, perhaps even bypassing the subclass altogether):
#pragma mark -
#pragma mark Event Passing
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[self.nextResponder touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[self.nextResponder touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[self.nextResponder touchesEnded:touches withEvent:event];
}
- (BOOL)touchesShouldCancelInContentView:(UIView *)view {
return NO;
}
Add this code to your view controller:
- (void)setupGestures {
UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(handlePinchGesture:)];
[self.view addGestureRecognizer:pinchGesture];
[pinchGesture release];
}
- (IBAction)handlePinchGesture:(UIPinchGestureRecognizer *)sender {
if ( sender.state == UIGestureRecognizerStateBegan ) {
//Hold values
previousLocation = [sender locationInView:self.view];
previousOffset = self.scrollView.contentOffset;
previousScale = self.scrollView.zoomScale;
} else if ( sender.state == UIGestureRecognizerStateChanged ) {
//Zoom
[self.scrollView setZoomScale:previousScale*sender.scale animated:NO];
//Move
location = [sender locationInView:self.view];
CGPoint offset = CGPointMake(previousOffset.x+(previousLocation.x-location.x), previousOffset.y+(previousLocation.y-location.y));
[self.scrollView setContentOffset:offset animated:NO];
} else {
if ( previousScale*sender.scale < 1.15 && previousScale*sender.scale > .85 )
[self.scrollView setZoomScale:1.0 animated:YES];
}
}
Please note that in this method there are references to a number of properties you must define in your view controller's class files:
CGFloat previousScale;
CGPoint previousOffset;
CGPoint previousLocation;
CGPoint location;
Ok that's it!
Unfortunately I could not get the scrollView to show its scrollers during the gesture. I tried all of these strategies:
//Scroll indicators
self.scrollView.showsVerticalScrollIndicator = YES;
self.scrollView.showsVerticalScrollIndicator = YES;
[self.scrollView flashScrollIndicators];
[self.scrollView setNeedsDisplay];
One thing I really enjoyed is if you'll look at the last line you'll note that it grabs any final zooming that's around 100% and just rounds it to that. You can adjust your tolerance level; I had seen this in Pages' zoom behavior and thought it would be a nice touch.
I put this in the viewDidLoad method and this accomplishes the scroll view handling the two touch pan behavior and another pan gesture handler handling the one touch pan behavior -->
scrollView.panGestureRecognizer.minimumNumberOfTouches = 2
let panGR = UIPanGestureRecognizer(target: self, action: #selector(ViewController.handlePan(_:)))
panGR.minimumNumberOfTouches = 1
panGR.maximumNumberOfTouches = 1
scrollView.gestureRecognizers?.append(panGR)
and in the handlePan method which is a function attached to the ViewController there is simply a print statement to verify that the method is being entered -->
#IBAction func handlePan(_ sender: UIPanGestureRecognizer) {
print("Entered handlePan numberOfTuoches: \(sender.numberOfTouches)")
}
HTH
Check out my solution:
#import “JWTwoFingerScrollView.h”
#implementation JWTwoFingerScrollView
- (id)initWithCoder:(NSCoder *)coder {
self = [super initWithCoder:coder];
if (self) {
for (UIGestureRecognizer* r in self.gestureRecognizers) {
NSLog(#“%#”,[r class]);
if ([r isKindOfClass:[UIPanGestureRecognizer class]]) {
[((UIPanGestureRecognizer*)r) setMaximumNumberOfTouches:2];
[((UIPanGestureRecognizer*)r) setMinimumNumberOfTouches:2];
}
}
}
return self;
}
-(void)firstTouchTimerFired:(NSTimer*)timer {
[self setCanCancelContentTouches:NO];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[self setCanCancelContentTouches:YES];
if ([event allTouches].count == 1){
touchesBeganTimer = [NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:#selector(firstTouchTimerFired:) userInfo: nil repeats:NO];
[touchesBeganTimer retain];
[touchFilter touchesBegan:touches withEvent:event];
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[touchFilter touchesMoved:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#“ended %i”,[event allTouches].count);
[touchFilter touchesEnded:touches withEvent:event];
}
-(void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
NSLog(#“canceled %i”,[event allTouches].count);
[touchFilter touchesCancelled:touches withEvent:event];
}
#end
It does not delays the first touch and does not stop when the user touches with two fingers after using one. Still it allows to cancel a just started one touch event using a timer.
Yes, you'll need to subclass UIScrollView and override its -touchesBegan: and -touchesEnded: methods to pass touches "up". This will probably also involve the subclass having a UIView member variable so that it knows what it's meant to pass the touches up to.
Kenshi's answer in Swift 4
for gestureRecognizer: UIGestureRecognizer in self.gestureRecognizers! {
if (gestureRecognizer is UIPanGestureRecognizer) {
let panGR = gestureRecognizer as? UIPanGestureRecognizer
panGR?.minimumNumberOfTouches = 2
}
}