I'm trying to override a method in my cellForRowAtIndexPath method like this
cell.customSwitch {
- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event
{
[super touchesEnded:touches withEvent:event];
NSLog(#"customSwitch touchesended");
}
};
however this isn't working (I'm normally a Java guy :P). Any help would be much appreciated!
There are a lot of similarities between Objective-C and Java, but that's not one of 'em. ;-)
If you want to create a cell with a customized -touchesEnded:withEvent: method, you'll need to declare and define that class separately. Something like:
#interface MyCell : UITableViewCell
{
//...
}
#end
#implementation MyCell
- (void)touchesEnded:(NSSet*)touches withEvent:(UIEvent*)event
{
[super touchesEnded:touches withEvent:event];
NSLog(#"customSwitch touchesended");
}
#end
Once you've done that, you can use MyCell in your -cellForRowAtIndexPath:.
Related
I have a tableview with 8 custom cells. in the 8th cell I added a scrollView with paging enabled so I can show page 1 and page 2 (or 3, 4... 10) without have a very high cell.
The problem is with the scrollView I can't use didSelectRowAtIndexPath because the cell is behind the scrollView so I'm trying to detect scrollView tap (not swipe).
I played with touchesBegan and touchesEnded but they are never called (I know touches work with UIView only, but maybe.....)
Any help is very appreciated.
Thanks,
Max
There is a trick Apple recommends to use in this case, in theirs WWDC 2014 session "Advanced scrollviews" (See Demo starting from 8:10):
[cell.contentView addSubview:_scrollView];
[_scrollView setUserInteractionEnabled:NO];
[cell.contentView addGestureRecognizer:_scrollView.panGestureRecognizer];
That's all what needs to be done, no need to override touchesBegan:, touchesMoved: and others.
I used solution based on overriding of touchesBegan:, touchesMoved:, touchesEnded: and touchesCancelled: previously, but sometimes it caused a weird behaviour: when select a certain cell, method -tableView:didSelectRowAtIndexPath: was called for cell with different indexPath.
Solution from Apple has no side effects so far and looks more elegant.
There is also an elegant resolution:
Create a SubClass from UIScrollView and override the following methods
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[[self superview]touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[[self superview]touchesMoved:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event
{
[[self superview]touchesCancelled:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
[[self superview]touchesEnded:touches withEvent:event];
}
Passing every touch to the superview of the scroll view and then the didSelectRowAtIndexPath will be called.
Solved subclassing both uitableviewcell and uiscrollview.
It worked for my needs. Hope it can help.
Max
myScrollView.h
#import <UIKit/UIKit.h>
#interface myScrollView : UIScrollView {
}
#end
myScrollView.m
#import "myScrollView.h"
#implementation myScrollView
- (id)initWithFrame:(CGRect)frame {
return [super initWithFrame:frame];
}
- (void) touchesEnded: (NSSet *) touches withEvent: (UIEvent *) event
{
NSLog(#"touch scroll");
// If not dragging, send event to next responder
if (!self.dragging)
[self.nextResponder touchesEnded: touches withEvent:event];
else
[super touchesEnded: touches withEvent: event];
}
myCell.h
#import <UIKit/UIKit.h>
#interface myCell : UITableViewCell {
}
#end
myCell.m
#import "myCell.h"
#implementation myCell
- (id)initWithFrame:(CGRect)frame {
return [super initWithFrame:frame];
}
- (void) touchesEnded: (NSSet *) touches withEvent: (UIEvent *) event
{
NSLog(#"touch cell");
// If not dragging, send event to next responder
[super touchesEnded: touches withEvent: event];
}
RootViewController.h
#import <UIKit/UIKit.h>
#class myCell;
#class myScrollView;
#interface RootViewController : UITableViewController {
myCell *cell;
myScrollView *scrollView;
}
#end
RootViewController.m
#pragma mark -
#pragma mark Table view data source
// Customize the number of sections in the table view.
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
return 1;
}
// Customize the number of rows in the table view.
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
return 3;
}
// Customize the appearance of table view cells.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *CellIdentifier = #"Cell";
// my custom cell
cell = [[myCell alloc] init];
if (cell == nil) {
cell = [[[myCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
}
// the custom scroll view
scrollView = [[myScrollView alloc] initWithFrame:cell.frame];
scrollView.contentSize = CGSizeMake(640, 40);
[cell.contentView addSubview:scrollView];
//something to add in scrollView
UILabel *label = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, 150, 20)];
label.text = #"some text";
[scrollView addSubview:label];
// Configure the cell.
return cell;
}
The selected answer is correct, but I updated the code based on a bug I was getting.
In the subclassed scroll view add the following code.
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
if (self.dragging) {
[super touchesMoved:touches withEvent:event];
} else {
if ([self.delegate isKindOfClass:[UITableViewCell class]]) {
[(UITableViewCell *)self.delegate touchesCancelled:touches withEvent:event];
}
[self.superview touchesMoved:touches withEvent:event];
}
}
If your self.delegate is not the UITableViewCell, than replace that property with a property to your cell.
The cell needs to retrieve the cancel touch event during movement to prevent the undesired results. It can be easily reproducible as follows.
Highlight the cell (assuming the scroll view is over the whole cell, if not highlight the scroll view)
While the cell is highlighted, drag the table view
Select any other cell and now the previously highlighted cell will retrieve the didSelectCell state
Another point to mention is that order matters! If the self.delegate is not called before the self.superview then the highlighted state wont happen.
I found the simplest solution for my needs:
subclass UIScrollView touchesEnded method and post a notification.
In the UITableview add an observer in viewdidAppear (remove it in viewdiddisappear) to call a function that call tableview didSelectRowForIndexPath.
Something like this (swift version)
// myScrollView.swift
import UIKit
class myScrollView: UIScrollView {
override func touchesEnded(touches: Set<UITouch>, withEvent event: UIEvent?) {
NSNotificationCenter.defaultCenter().postNotificationName("selectTVRow", object: nil)
}
}
In your tableView:
// ItemsList.swift
override func viewDidAppear(animated: Bool) {
super.viewDidAppear(animated)
NSNotificationCenter.defaultCenter().addObserver(self, selector: "selectFourthRow", name: "selectTVRow", object: nil)
}
override func viewDidDisappear(animated: Bool) {
super.viewDidDisappear(animated)
NSNotificationCenter.defaultCenter().removeObserver(self, name: "selectfourthrow", object: nil)
}
func selectFourthRow() {
let rowToSelect:NSIndexPath = NSIndexPath(forRow: 4, inSection: 0);
self.tableView(self.tableView, didSelectRowAtIndexPath: rowToSelect);
}
/*
.... rest of your tableview Datasource and Delegate methods...
numberOfSectionsInTableView, numberOfRowsInSection, cellForRowAtIndexPath
*/
I was trying to find a way to recognise a touch&hold on my buttons. I thought that to subclass my buttons was a good idea, but I'm now struggling with the whole idea of subclasses, parentsviews and the viewcontroller. So please forgive, I fear that this is a beginner's question:
How do I call a method (which I've defined in my ViewController) from a subclassed UIButton?
[self someMethod]; doesn't work - as UIButton is not a descendent of my ViewController.
[super someMethod]; doesn't work either - same problem I suppose
[self.superview someMethod]; ... again no luck
[MyViewController someMethod]; doesn't work either -- as it is 'undecleared' -- do I have to import my ViewController? Or do some kind of protocol/class call?
Any help would be very much appreciated.
Here is my subclass:
//
// MoleButton.h
//
#import <Foundation/Foundation.h>
#interface MoleButton : UIButton {
int page;
NSString *colour;
UIViewController *theViewController;
NSTimer *holdTimer;
}
#property (nonatomic, assign) int page;
#property (nonatomic, assign) NSString *colour;
#end
//
// MoleButton.m
#import "MoleButton.h"
#implementation MoleButton
#synthesize page, colour;
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesBegan:touches withEvent:event];
[self.superview touchesBegan:touches withEvent:event];
[holdTimer invalidate];
holdTimer = [NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:#selector(touchWasHeld) userInfo:nil repeats:NO];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesMoved:touches withEvent:event];
[self.superview touchesMoved:touches withEvent:event];
[holdTimer invalidate];
holdTimer = nil;
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
[super touchesEnded:touches withEvent:event];
[self.superview touchesEnded:touches withEvent:event];
}
- (void)touchWasHeld
{
holdTimer = nil;
// do your "held" behavior here
NSLog(#"TOUCH WAS HELD!!!!");
[self.theViewController doSomething];
}
#end
You can simply add a property in the subclassed UIButton class, which holds the view controller. When initializing it, you need to add the controller, for sure.
Use the very simple delegate concept of Objective-C .
Check my answer in the below post for using delegate in Objective-C .
How do I set up a simple delegate to communicate between two view controllers?
How do I capture touch events such as - (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event without subclassing a UIView nor using UIViewControllers.
What happens is that I have a simple UIView created programmatically and I need to detect basic tap events.
If you are writing your app for iOS 4, use UIGestureRecognizer. You can then do what you want. Recognize gestures without subclassing.
Otherwise, subclassing is the way to go.
There's just no reason not to. If you subclass and add nothing it's just a UIView called by another name. All you are doing is intercepting those functions that you are interested in. Don't forget you can do [super touchesBegan:touches] inside your subclass' touchesBegan if you don't want to stop responders up the chain from getting those events too.
I don't why you don't want to use the normal method of subclassing a UIView to capture touch events, but if you really need to do something weird or sneaky, you can capture all events (including touch events) before they get sent down the view hierarchy by trapping/handling the sendEvent: method at the UIWindow level.
CustomGestureRecognizer.h
#import <UIKit/UIKit.h>
#interface CustomGestureRecognizer : UIGestureRecognizer
{
}
- (id)initWithTarget:(id)target;
#end
CustomGestureRecognizer.mm
#import "CustomGestureRecognizer.h"
#import <UIKit/UIGestureRecognizerSubclass.h>
#interface CustomGestureRecognizer()
{
}
#property (nonatomic, assign) id target;
#end
#implementation CustomGestureRecognizer
- (id)initWithTarget:(id)target
{
if (self = [super initWithTarget:target action:Nil]) {
self.target = target;
}
return self;
}
- (void)reset
{
[super reset];
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesBegan:touches withEvent:event];
[self.target touchesBegan:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesMoved:touches withEvent:event];
[self.target touchesMoved:touches withEvent:event];
}
- (void) touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
[super touchesEnded:touches withEvent: event];
[self.target touchesEnded:touches withEvent:event];
}
#end
Usage:
CustomGestureRecognizer *customGestureRecognizer = [[CustomGestureRecognizer alloc] initWithTarget:self];
[glView addGestureRecognizer:customGestureRecognizer];
I have a UITextView in a custom UITableViewCell. The textview works properly (scrolls, shows text, etc.) but I need the users to be able to tap the table cell and go to another screen. Right now, if you tap the edges of the table cell (i.e. outside the UItextView) the next view is properly called. But clearly inside the uitextview the touches are being captured and not forwarded to the table cell.
I found a post that talked about subclassing UITextView to forward the touches. I tried that without luck. The implementation is below. I'm wondering if maybe a) the super of my textview isn't the uitableviewcell and thus I need to pass the touch some other way or b) If the super is the uitableviewcell if I need to pass something else? Any help would be much appreciated.
#import "ScrollableTextView.h"
#implementation ScrollableTextView
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if (parentScrollView) {
[parentScrollView touchesBegan:touches withEvent:event];
}
[super touchesBegan:touches withEvent:event];
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
if (parentScrollView) {
[parentScrollView touchesCancelled:touches withEvent:event];
}
[super touchesCancelled:touches withEvent:event];
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
if (parentScrollView) {
[parentScrollView touchesEnded:touches withEvent:event];
}
[super touchesEnded:touches withEvent:event];
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
if (parentScrollView) {
[parentScrollView touchesMoved:touches withEvent:event];
}
[super touchesMoved:touches withEvent:event];
}
- (BOOL)canBecomeFirstResponder {
return YES;
}
#end
Try [theTextView setUserInteractionEnabled:NO]; If the user needs to be able to edit the contents of the TextView, then you might have a design problem here.
Swift 3 : theTextView.isUserInteractionEnabled = false
Storyboard : tick the "User Interaction Enabled" checkbox.
I know that this question has been asked 5 years ago, but the behaviour is still very much needed for some app to have a clickable Cell with UIDataDetectors.
So here's the UITextView subclass I made up to fit this particular behaviour in a UITableView
-(id) initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
self.delegate = self;
}
return self;
}
- (BOOL)canBecomeFirstResponder {
return NO;
}
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
UIView *obj = self;
do {
obj = obj.superview;
} while (![obj isKindOfClass:[UITableViewCell class]]);
UITableViewCell *cell = (UITableViewCell*)obj;
do {
obj = obj.superview;
} while (![obj isKindOfClass:[UITableView class]]);
UITableView *tableView = (UITableView*)obj;
NSIndexPath *indePath = [tableView indexPathForCell:cell];
[[tableView delegate] tableView:tableView didSelectRowAtIndexPath:indePath];
}
- (BOOL)textView:(UITextView *)textView shouldInteractWithURL:(NSURL *)URL inRange:(NSRange)characterRange {
return YES;
}
You can modify this to fit your needs...
Hope it helps someone.
The problem with your solution is that if you put UITextView inside UITableViewCell, its superview won't be the actual cell. There's even a slight difference between iOS 7 and iOS 8 on the cell's view structure. What you need to do is drill down (or drill up) through the hierarchy to get UITableViewCell instance.
I am using and modifying #TheSquad's while loop to get the UITableViewCell, and assign it to a property. Then override those touch methods, use the cell's touches method whenever needed, and just use super's touch method's implementations to get the default behaviour.
// set the cell as property
#property (nonatomic, assign) UITableViewCell *superCell;
- (UITableViewCell *)superCell {
if (!_superCell) {
UIView *object = self;
do {
object = object.superview;
} while (![object isKindOfClass:[UITableViewCell class]] && (object != nil));
if (object) {
_superCell = (UITableViewCell *)object;
}
}
return _superCell;
}
#pragma mark - Touch overrides
- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
if (self.superCell) {
[self.superCell touchesBegan:touches withEvent:event];
} else {
[super touchesBegan:touches withEvent:event];
}
}
- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
if (self.superCell) {
[self.superCell touchesMoved:touches withEvent:event];
} else {
[super touchesMoved:touches withEvent:event];
}
}
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
if (self.superCell) {
[self.superCell touchesEnded:touches withEvent:event];
} else {
[super touchesEnded:touches withEvent:event];
}
}
- (void)touchesCancelled:(NSSet *)touches withEvent:(UIEvent *)event {
if (self.superCell) {
[self.superCell touchesEnded:touches withEvent:event];
} else {
[super touchesCancelled:touches withEvent:event];
}
}
The answers above don't solve the problem if you have links in the UITextView and want them to work as usual when user taps a link, and pass the tap to the cell if user taps regular text. With the proposed method cell will be "selected" in both cases.
Here are some possible solutions:
https://stackoverflow.com/a/59010352/11448489 - add a tap gesture recognizer to the cell, and set it to require UITextInteractionNameLinkTap recognizer failure. The problem is that UITextInteractionNameLinkTap string is from internal Apple API and can change. Also, we still have to directly call delegate's didSelectRowAtIndexPath, so the cell won't be animated.
Implement override of touchesEnded in the text view. In it perform some selector after delay of at least 0.4s. In the text view delegate cancel this perform request if an interaction with url happened:
class TappableTextView: UITextView, UITextViewDelegate {
var tapHandler: (() -> Void)?
override var delegate: UITextViewDelegate? {
get { self }
set { }
}
override func touchesEnded(_ touches: Set<UITouch>, with event: UIEvent?) {
self.perform(#selector(onTap), with: nil, afterDelay: 0.5)
}
func textView(_ textView: UITextView, shouldInteractWith URL: URL, in characterRange: NSRange, interaction: UITextItemInteraction) -> Bool {
Self.cancelPreviousPerformRequests(withTarget: self, selector: #selector(onTap), object: nil)
return true
}
#objc func onTap() {
self.tapHandler?()
}
}
It works, but delay is noticeable and annoying. It is not possible to reduce this delay because shouldInteractWith happens after 350ms after touchesEnded.
And we still have to call didSelectRowAtIndexPath.
I came to another solution, which seems to work perfectly if you need clickable links, but no other interactions (not scrollable, selectable etc). Essentially, we need to make the text view ignore all touches which are not in the links area:
class TapPassingTextView: UITextView, UITextViewDelegate {
var clickableRects = [CGRect]()
override func layoutSubviews() {
super.layoutSubviews()
self.updateClickableRects()
}
override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
clickableRects.contains { $0.contains(point) } ? super.hitTest(point, with: event) : nil
}
private func updateClickableRects() {
self.clickableRects = []
let range = NSRange(location: 0, length: self.attributedText.string.count)
self.attributedText.enumerateAttribute(.link, in: range) { link, range, _ in
guard link != nil else { return }
self.layoutManager.enumerateLineFragments(forGlyphRange: range) { rect, _, _, _, _ in
self.clickableRects.append(rect)
}
}
}
}
That's it! Taps on links are working and taps in other areas go below the text view, cells are selected natively.
I want to preface this question with the fact I am new to the iphone application development and many times believe I may be over my head. I am trying to find an action that will allow me to double tap anywhere within my full screen UIScrollView to return to my main menu (MainMenuViewController).
I currently have the following code running for my ScrollViewController...
ScrollViewController.h
#import <UIKit/UIKit.h>
#interface ScrollViewController : UIViewController <UIScrollViewDelegate>
{
}
#end
ScrollViewController.m
#import "ScrollViewController.h"
UIScrollView *myScrollView;
UIPageControl *myPageControl;
#implementation ScrollViewController
- (void)loadScrollViewWithPage:(UIView *)page
{
int pageCount = [[myScrollView subviews] count];
CGRect bounds = myScrollView.bounds;
bounds.origin.x = bounds.size.width * pageCount;
bounds.origin.y = 0;
page.frame = bounds;
[myScrollView addSubview:page];
}
...etc
Any advice or sample code to implement a double tap within the ScrollView Controller to allow me to return to my MainMenuViewController would be greatly appreciated. Also please include any Interface Builder changes to the view (if necessary). I have been pouring over the forums for days and have not been able to successfully implement this action. Thanks...R.J.
First of all, create a subclass of a UIScrollView:
#import <UIKit/UIKit.h>
#interface MyScrollView : UIScrollView {
}
#end
Implement it:
#import "MyScrollView.h"
#implementation MyScrollView
- (void) touchesEnded: (NSSet *) touches withEvent: (UIEvent *) event {
if (!self.dragging) {
[self.nextResponder touchesEnded: touches withEvent:event];
}
[super touchesEnded: touches withEvent: event];
}
- (void)dealloc {
[super dealloc];
}
#end
Then, use this subclass instead of a normal UIScrollView in your main View Controller. This will call the touchesEnded:withEvent: method (alternatively, you can call any method you want). Then, track for double taps (if you need info on how to do that, let me know).