I have added one scrollview and imageview to my view. When I touch on this imageview my scrollview scrolls. And within my scrollview there are lots of imageviews which have touch events written separately.
Here is the view hierarchy
View
|
|
------- --------
| |
imageView1 scrollview
|
...........................
| | |.....|
imageviews2
Imageview1 is above imagesview2 in appearance.
And when I scroll the scrollview it is not possible to touch some of the imageViews within the scrollview as it comes behind the imageview within view.
How can I pass the touch events to the imageviews2 whenever it is behind imageview1.
You'll need to subclass UIView and override
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
in that subclass to skip imageView1.
You might get away with subclassing UIImageView and instantiating imageView1 as a member of that class, and overriding pointInside
- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event
{ return NO; }
don't forget also to uncheck "delays content touches" and "cancellable content touches" on your scrollview !
I hope this answer might be useful for someone. I have done it without using hittest.
Took all the subviews in scrollview and checked if it is an image view and did the following.
Passed the touchevents to another view using [view touchesBegan:touches withEvent:event]; we have to write the same in touchesMoved and touchesEnded also.
Thanks,
Joku
You need to pass the touch event to the UIViews that are outside the bounds of the parent view.
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event {
// Convert the point to the target view's coordinate system.
// The target view isn't necessarily the immediate subview
CGPoint pointForTargetView = [self.targetView convertPoint:point fromView:self];
if (CGRectContainsPoint(self.targetView.bounds, pointForTargetView)) {
// The target view may have its view hierarchy,
// so call its hitTest method to return the right hit-test view
return [self.targetView hitTest:pointForTargetView withEvent:event];
}
return [super hitTest:point withEvent:event];
}
https://developer.apple.com/library/ios/qa/qa2013/qa1812.html
I have a uiview at the top of the interface (below the status bar) that only the bottom part of it is shown.
Actually, I want to make the red uiview to slide down to be entirely shown by drag such as the notificationcenter in the native iOS and not just by taping a button.
What should I use to "touch and pull down" the uiview so it could be shown entirely ?
No needs to find a workaround of drag-n-drop. An UIScrollView can do it without any performance loss brought by listening on touches.
#interface PulldownView : UIScrollView
#end
#implementation PulldownView
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (!self) {
return self;
}
self.pagingEnabled = YES;
self.bounces = NO;
self.showsVerticalScrollIndicator = NO;
[self setBackgroundColor:[UIColor clearColor]];
double pixelsOutside = 20;// How many pixels left outside.
self.contentSize = CGSizeMake(320, frame.size.height * 2 - pixelsOutside);
// redArea is the draggable area in red.
UIView *redArea = [[UIView alloc] initWithFrame:frame];
redArea.backgroundColor = [UIColor redColor];
[self addSubview:redArea];
return self;
}
// What this method does is to make sure that the user can only drag the view from inside the area in red.
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
if (point.y > height)
{
// Leaving useless touches to the views under it.
return nil;
}
return [super hitTest:point withEvent:event];
}
#end
How to use:
1. Initialize an instance of PulldownView.
2. Add any content you want to display to the instance using [addSubview:].
3. Hide the area in red.
[pulldownView setContentOffset:CGPointMake(0, heightOfTheView - pixelsOutside)];
This is a simple example. You can add any features to it like adding a titled button bar on the bottom of the draggable area to implement click-n-drop, or adding some method to the interface to reposition it by the caller.
Make a subclass of UIView.
Override touchesBegan:withEvent and touchesMoved:withEvent.
In the touchesBegan perhaps make a visual change so the user knows they are touching the view.
In the touchesMoved use
[[touches anyObject] locationInView:self]
and
[[touches anyObject] previousLocationInView:self]
to calculate the difference between the current touch position and the last touch position (detect drag down or drag back up).
Then if you're custom drawing, call [self setNeedsDisplay] to tell your view to redraw in it's drawRect:(CGRect)rect method.
Note: this assumes multiple touch is not used by this view.
Refer to my answer in iPhone App: implementation of Drag and drop images in UIView
You just need to use TouchesBegin and TouchesEnded methods. In that example, I have shown how to use CGPoint, Instead of that you have to try to use setFrame or drawRect for your view.
As soon as TouchesMoved method is called you have to use setFrame or drawRect (not sure but which ever works, mostly setFrame) also take the height from CGPoint.
I have created a 3 Subviews to MyView by creating new class inherits from UIView.
then i tried to change text in a particular subview say second sub view.
But its not updating.So how to do this...
EDIT
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
CALayer *hitLater = [self layerForTouch:[touches anyObject]];
if ([hitLater isKindOfClass:[Tile class]])
{
Tile *tile = (Tile *)hitLater;
heldTile = tile;
[tile draw2];
[tile setNeedsDisplay];
}
}
Thanks in advance..
If you want a better answer show some code and how you add the text to your UIView subclasses etc.
But maybe you have to call setNeedsDisplay on your subviews so they get a redraw.
Right now I have 2 different UIPickerView in side my UITableViewController. I only show them upon tapping of certain cells in the table. What I'm trying to do is to hide the pickers whenever I touch outside the pickers. Is there a delegate method or something similar to achieve this? I prefer to keep my controller as a UITableViewController instead of a simple UIViewController since I have a textView in one of the cells and scrolling after the keyboard shows is just a bit too much in a UIViewController.
Thanks in advance.
One of the Possible solutions is that when a particular cell is tapped and you handle picker (to present the picker), you can insert a view called as MASK View over the tableview. (with Frame as self.tableview.frame - yourPicker.frame.size.height ). Now when ever you get any click on this view you can handle it as follows
-(void)showMaskView{
if (!viewMaskView) {
CGRect viewRect = CGRectMake(0, 0, self.tableView.frame.size.width, self.tableView.frame.size.height - yourPicker.frame.size.height);
viewMaskView = [[MaskView alloc] initWithFrame:viewRect];
viewMaskView.delegate = self;
}
[self.view addSubview:viewMaskView];
[self.view bringSubviewToFront:viewMaskView];
}
-(void)removeMaskView{
if (viewMaskView) {
[viewMaskView removeFromSuperview];
}
//Remove the Picker
}
In the MaskView class you can handle the touch as follows
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
if(self.delegate && [self.delegate respondsToSelector:#selector(removeMaskView)])
[self.delegate removeMaskView];
}
you can see the colored mask view over the Picker in the image. When tapped it removes picker.
I have a view with multiple subviews. When a user taps a subview, the subview expands in size to cover most of the screen, but some of the other subviews are still visible underneath.
I want my app to ignore touches on the other subviews when one of the subviews is "expanded" like this. Is there a simple way to achieve this? I can write code to handle this, but I was hoping there's a simpler built-in way.
Hope this help...
[[yourSuperView subviews]
makeObjectsPerformSelector:#selector(setUserInteractionEnabled:)
withObject:[NSNumber numberWithBool:FALSE]];
which will disable userInteraction of a view's immediate subviews..Then give userInteraction to the only view you wanted
yourTouchableView.setUserInteraction = TRUE;
EDIT:
It seems in iOS disabling userInteraction on a parent view doesn't disable userInteraction on its childs.. So the code above (I mean the one with makeObjectsPerformSelector:)will only work to disable userInteraction of a parent's immediate subviews..
See user madewulf's answer which recursively get all subviews and disable user interaction of all of them. Or if you need to disable userInteraction of this view in many places in the project, You can categorize UIView to add that feature.. Something like this will do..
#interface UIView (UserInteractionFeatures)
-(void)setRecursiveUserInteraction:(BOOL)value;
#end
#implementation UIView(UserInteractionFeatures)
-(void)setRecursiveUserInteraction:(BOOL)value{
self.userInteractionEnabled = value;
for (UIView *view in [self subviews]) {
[view setRecursiveUserInteraction:value];
}
}
#end
Now you can call
[yourSuperView setRecursiveUserInteraction:NO];
Also user #lxt's suggestion of adding an invisible view on top of all view's is one other way of doing it..
There are a couple of ways of doing this. You could iterate through all your other subviews and set userInteractionEnabled = NO, but this is less than ideal if you have lots of other views (you would, after all, have to subsequently renable them all).
The way I do this is to create an invisible UIView that's the size of the entire screen that 'blocks' all the touches from going to the other views. Sometimes this is literally invisible, other times I may set it to black with an alpha value of 0.3 or so.
When you expand your main subview to fill the screen you can add this 'blocking' UIView behind it (using insertSubview: belowSubview:). When you minimize your expanded subview you can remove the invisible UIView from your hierarchy.
So not quite built-in, but I think the simplest approach. Not sure if that was what you were thinking of already, hopefully it was of some help.
Beware of the code given as solution here by Krishnabhadra:
[[yourSuperView subviews]makeObjectsPerformSelector:#selector(setUserInteractionEnabled:) withObject:[NSNumber numberWithBool:FALSE]];
This will not work in all cases because [yourSuperView subviews] only gives the direct subviews of the superview. To make it work, you will have to iterate recursively on all subviews:
-(void) disableRecursivelyAllSubviews:(UIView *) theView
{
theView.userInteractionEnabled = NO;
for(UIView* subview in [theView subviews])
{
[self disableRecursivelyAllSubviews:subview];
}
}
-(void) disableAllSubviewsOf:(UIView *) theView
{
for(UIView* subview in [theView subviews])
{
[self disableRecursivelyAllSubviews:subview];
}
}
Now a call to disableAllSubviewsOf will do what you wanted to do.
If you have a deep stack of views, the solution by lxt is probably better.
I would do this by putting a custom transparent button with the same frame as the superView. And then on top of that button I would put view that should accept user touches.
Button will swallow all touches and views behind it wouldn't receive any touch events, but view on top of the button will receive touches normally.
Something like this:
- (void)disableTouchesOnView:(UIView *)view {
UIButton *ghostButton = [[UIButton alloc] initWithFrame:CGRectMake(0, 0, view.frame.size.width, view.frame.size.height)];
[ghostButton setBackgroundColor:[UIColor clearColor]];
ghostButton.tag = 42; // Any random number. Use #define to avoid putting numbers in code.
[view addSubview:ghostButton];
}
And a method for enabling the parentView.
- (void)enableTouchesOnView:(UIView *)view {
[[view viewWithTag:42] removeFromSuperview];
}
So, to disable all views in the parentViev behind yourView, I would do this:
YourView *yourView = [[YourView alloc] initWithCustomInitializer];
// It is important to disable touches on the parent view before adding the top most view.
[self disableTouchesOnView:parentView];
[parentView addSubview:yourView];
Just parentView.UserInteractionEnabled = NO will do the work.
Parent view will disable user interaction on all the view's subviews. But enable it does not enable all subviews(by default UIImageView is not interactable). So an easy way is find the parent view and use the code above, and there is no need to iterate all subviews to perform a selector.
Add a TapGestureRecognizer to your "background view" (the translucent one which "grays out" your normal interface) and set it to "Cancels Touches In View", without adding an action.
let captureTaps = UITapGestureRecognizer()
captureTaps.cancelsTouchesInView = true
dimmedOverlay?.addGestureRecognizer(captureTaps)
I will give my 2 cents to this problem.
Iteratively run userInteractionEnabled = false it's one way.
Another way will be add a UIView like following.
EZEventEater.h
#import <UIKit/UIKit.h>
#interface EZEventEater : UIView
#end
EZEventEater.m
#import "EZEventEater.h"
#implementation EZEventEater
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self) {
// Initialization code
self.backgroundColor = [UIColor clearColor];
self.userInteractionEnabled = false;
}
return self;
}
- (void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
//EZDEBUG(#"eater touched");
}
- (void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
}
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
}
In your code you add the EZEventEater view to cover all the views that your may block the touch event.
Whenever you want to block the touch event to those views, simply call
eater.userInteractionEnabled = YES;
Hope this helpful.
In Swift 5, I achieved this behaviour by placing a view right on top(the highlighted one) and setting:
myView.isUserInteractionEnabled = true
This does not let the touches go through it, thus ignoring the taps.
For my app, I think it will be sufficient to disable navigation to other tabs of the app (for a limited duration, while I'm doing some processing):
self.tabBarController.view.userInteractionEnabled = NO;
Also, I disabled the current view controller--
self.view.userInteractionEnabled = NO;
(And, by the way, the recursive solutions proposed here had odd effects in my app. The disable seems to work fine, but the re-enable has odd effects-- some of the UI was not renabled).
Simple solution. Add a dummy gesture that does nothing. Make it reusable by adding it to an extension like this:
extension UIView {
func addNullGesture() {
let gesture = UITapGestureRecognizer(target: self,
action: #selector(nullGesture))
addGestureRecognizer(gesture)
}
#objc private func nullGesture() {}
}
setUserInteractionEnabled = NO on the view you want to disable
I had the same problem, but the above solutions did not help.
I then noticed that calling
super.touchesBegan(...) was the problem.
After removing this the event was only handled by the top-most view.
I hope this is of help to anybody.