Changing the model after tapping a UIButton in a custom UITableViewCell - ios

I am looking for is a clean way of changing the model after tapping a button in a custom cell. It's tapping the button that matters here and not selecting the row, so didSelectRowAtIndexPath isn't what I am interested in.
For example
let array = [true, false, true]
When the user taps the button in the second cell, the model should become
array[1] = true
In cellForRowAtIndexPath a target action is added to the button :
cell.button.addTarget(self, action: "myAction:", forControlEvents: UIControlEvents.TouchUpInside)
the action looks like :
func myAction(sender:UIButton!)
{
//how to change the model and reloadRowsAtIndexPaths since the sender is just a UIButton!?
}


If you only have one section in the tableViewController, you could always set button.tag = [indexPath row] inside cellForRowAtIndexPath. Then your action would always know which row was touched from the sender.tag value. Quick and dirty, but it would work.
Or, if you will reuse this custom cell in tableviews with multiple sections, you could subclass the UIButton and add a property for the indexPath. Then you would always have access to both section and row values. Personally, I would take this approach because it gives you the most flexibility in the long run.


inside of cellForRowAtIndexPath()
cell.button.tag = indexPath.row
Then inside of your function myAction()
func myAction(sender:UIButton)
{
var index = sender.view.tag
array[index] = true // just like you want
}


I am a little unclear about your question - are you asking how you can change a uitableviewcell's content once a button is pressed in the cell then one way to go about it would be to tag the button with the cell's indexPath when the cell is created in the cellForRowAtIndexPath method. Then you can read the tag from the selector once the button is pushed.
I just tested this and it works. When you create the cell add the line:
cell.tag=indexPath.row;
and then in the selector method for the button you can use:
NSInteger p=sender.tag;
int x=(int)p;
NSIndexPath *path = [NSIndexPath indexPathForRow:x inSection:0];
UITableViewCell *cell = [_tableView cellForRowAtIndexPath:path];
cell.backgroundColor=[UIColor blackColor];
In my example I changed the background color of the cell that the pressed button was in.

Related

Correct way to setting a tag to all cells in TableView

I'm using a button inside a tableView in which I get the indexPath.row when is pressed. But it only works fine when the cells can be displayed in the screen without scroll.
Once the tableView can be scrolleable and I scrolls throught the tableview, the indexPath.row returned is a wrong value, I noticed that initially setting 20 objects, for example Check is just printed 9 times no 20.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil) {
cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
lBtnWithAction = [[UIButton alloc] initWithFrame:CGRectMake(liLight1Xcord + 23, 10, liLight1Width + 5, liLight1Height + 25)];
lBtnWithAction.tag = ROW_BUTTON_ACTION;
lBtnWithAction.titleLabel.font = luiFontCheckmark;
lBtnWithAction.tintColor = [UIColor blackColor];
lBtnWithAction.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin;
[cell.contentView addSubview:lBtnWithAction];
}
else
{
lBtnWithAction = (UIButton *)[cell.contentView viewWithTag:ROW_BUTTON_ACTION];
}
//Set the tag
lBtnWithAction.tag = indexPath.row;
//Add the click event to the button inside a row
[lBtnWithAction addTarget:self action:#selector(rowButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
//This is printed just 9 times (the the number of cells that are initially displayed in the screen with no scroll), when scrolling the other ones are printed
NSLog(#"Check: %li", (long)indexPath.row);
return cell;
}
To do something with the clicked index:
-(void)rowButtonClicked:(UIButton*)sender
{
NSLog(#"Pressed: %li", (long)sender.tag);
}
Constants.h
#define ROW_BUTTON_ACTION 9
What is the correct way to get the indexPath.row inside rowButtonClicked or setting a tag when I have a lot of of cells in my tableView?

My solution to this kind of problem is not to use a tag in this way at all. It's a complete misuse of tags (in my opinion), and is likely to cause trouble down the road (as you've discovered), because cells are reused.
Typically, the problem being solved is this: A piece of interface in a cell is interacted with by the user (e.g. a button is tapped), and now we want to know what row that cell currently corresponds to so that we can respond with respect to the corresponding data model.
The way I solve this in my apps is, when the button is tapped or whatever and I receive a control event or delegate event from it, to walk up the view hierarchy from that piece of the interface (the button or whatever) until I come to the cell, and then call the table view's indexPath(for:), which takes a cell and returns the corresponding index path. The control event or delegate event always includes the interface object as a parameter, so it is easy to get from that to the cell and from there to the row.
Thus, for example:
UIView* v = // sender, the interface object
do {
v = v.superview;
} while (![v isKindOfClass: [UITableViewCell class]]);
UITableViewCell* cell = (UITableViewCell*)v;
NSIndexPath* ip = [self.tableView indexPathForCell:cell];
// and now we know the row (ip.row)
[NOTE A possible alternative would be to use a custom cell subclass in which you have a special property where you store the row in cellForRowAt. But this seems to me completely unnecessary, seeing as indexPath(for:) gives you exactly that same information! On the other hand, there is no indexPath(for:) for a header/footer, so in that case I do use a custom subclass that stores the section number, as in this example (see the implementation of viewForHeaderInSection).]

I agree with #matt that this is not a good use of tags, but disagree with him slightly about the solution. Instead of walking up the button's superviews until you find a cell, I prefer to get the button's origin, convert it to table view coordinates, and then ask the table view for the indexPath of the cell that contains those coordinates.
I wish Apple would add a function indexPathForView(_:) to UITableView. It's a common need, and easy to implement. To that end, here is a simple extension to UITableView that lets you ask a table view for the indexPath of any view that lies inside one of the tableView's cells.
Below is the key code for the extension, in both Objective-C and Swift. There is a working project on GitHub called TableViewExtension-Obj-C that illustrates the uses of the table view extension below.
EDIT
In Objective-C:
Header file UITableView_indexPathForView.h:
#import <UIKit/UIKit.h>
#interface UIView (indexPathForView)
- (NSIndexPath *) indexPathForView: (UIView *) view;
#end
UITableView_indexPathForView.m file:
#import "UITableView_indexPathForView.h"
#implementation UITableView (UITableView_indexPathForView)
- (NSIndexPath *) indexPathForView: (UIView *) view {
CGPoint origin = view.bounds.origin;
CGPoint viewOrigin = [self convertPoint: origin fromView: view];
return [self indexPathForRowAtPoint: viewOrigin];
}
And the IBAction on the button:
- (void) buttonTapped: (UIButton *) sender {
NSIndexPath *indexPath = [self.tableView indexPathForView: sender];
NSLog(#"Button tapped at indexpPath [%ld-%ld]",
(long)indexPath.section,
(long)indexPath.row);
}
In Swift:
import UIKit
public extension UITableView {
func indexPathForView(_ view: UIView) -> IndexPath? {
let origin = view.bounds.origin
let viewOrigin = self.convert(origin, from: view)
let indexPath = self.indexPathForRow(at: viewOrigin)
return indexPath
}
}
I added this as a file "UITableView+indexPathForView" to a test project to make sure I got everything correct. Then in the IBAction for a button that is inside a cell:
func buttonTapped(_ button: UIButton) {
let indexPath = self.tableView.indexPathForView(button)
print("Button tapped at indexPath \(indexPath)")
}
I made the extension work on any UIView, not just buttons, so that it's more general-purpose.
The nice thing about this extension is that you can drop it into any project and it adds the new indexPathForView(_:) function to all your table views without having do change your other code at all.

You are running into the issue of cell-reuse.
When you create a button for the view you set a tag to it, but then you override this tag to set the row number to it.
When the cell get's reused, because the row number is longer ROW_BUTTON_ACTION, you don't reset the tag to the correct row number and things go wrong.
Using a tag to get information out of a view is almost always a bad idea and is quite brittle, as you can see here.
As Matt has already said, walking the hierarchy is a better idea.
Also, your method doesn't need to be written in this way. If you create your own custom cell, then the code you use to create and add buttons and tags isn't needed, you can do it in a xib, a storyboard, or even in code in the class. Furthermore, if you use the dequeue method that takes the index path, you will always get either a recycled cell, or a newly created cell, so there is no need to check that the cell returned is not nil.

When the button in TableView cell pressed, how do I know the button of which row of cell pressed?

I have a custom TableView cell, and in that there's a button.
The table view have many rows used the same custom cell.
Now if the button of one of the cells pressed. I want to know which row of cell the button is in?

(1). In this method cellForRowAtIndexPath: , assign button with a tag.
For example:
cell.yourbutton.tag = indexPath.row;
(2). Add action for you button with same selector
[cell.yourbutton addTarget:self action:#selector(cellButtonClicked:) forControlEvents:UIControlEventTouchUpInside];
(3). Then
-(void)cellButtonClicked:(UIButton*)sender
{
NSIndexPath *path = [NSIndexPath indexPathForRow:sender.tag inSection:0];
}

You can define your custom property and you can use it like below:-
#define kCustomProperty #"CustomProperty"
Associate your object with that custom property like below
objc_setAssociatedObject(yourButton,kCustomProperty , yourCellIndexPath, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
Get your data using the same property and object like below
NSIndexPath *yourCellIndexPath = (NSIndexPath *)objc_getAssociatedObject(yourButton, kCustomProperty);
Its a kind of custom property you can create by coding if you don't want to use tag.

How to select multiple cells in a table view

I have a table view with multiple cells. When I click on one of the cell it navigates to the next view controller, but my problem is that I cannot select multiple cells.
Could any one please help me on this issue, I want to select two or more cells with two finger tap.

set by code if you set by programming
table.allowsMultipleSelection = YES;
and if you set in xib tick on allowsMultipleSelection

Just add button like checkbox and multiple choose like checkbox.

If you are implementing the tableview programatically then the better way is to create a custom cell which will have button (and obviously other UI components that you need to show in the table view cell) which will work as a checkbox and assign button.tag as indexPath.row which will help you to select multiple rows.
Take a look here --
Below code will go into cellForRowAtIndexPath
YourCustomCell *cell = [tableView dequeueReusableCellWithIdentifier:#"Cell" forIndexPath:indexPath];
cell.button.tag = indexPath.row;
[cell.button addTarget:self action:#selector(multipleCheckAction:) forControlEvents:UIControlEventTouchUpInside];
return cell;
-(void)multipleCheckAction:(UIButton *)sender { //sender.tag will be equal to indexPath.row }
Happy Coding

Since cells are being reused, you need to set the accessory mark to on or off for every cell in the table in the cellForRowAtIndexPath table datasource method.
So the cell.accessoryType cell property should be specified in the cellForRowAtIndexPath and not the didSelectRowAtIndexPath delegate method.
In the didSelectRow, just keep track of the selected rows in an array, and set the cells accessory mark to none or checkmark in the cellForRowAtIndexPath depending on the array value.

iOS: willSelectRowAtIndexPath called on bottom of tableViewCell

I have a custom UITableViewCell that has 2 buttons and a label on it. The problem is that willSelectRowAtIndexPath only gets called when I click right above the bottom of a cell.
I set User Interaction Enabled to true for the UITableViewCell. This allows the buttons I have in my cell to be clickable.
If I set it to false, I willSelectRowAtIndexPath gets called when I click anywhere in the cell but the buttons no longer work.
Please help!

I am not sure if the button can let that happen automatically when enabled. However we can let the cell know that it was selected.
- (IBAction)respondToClick:(id)sender {
CustomTableViewCell *customCell = (CustomTableViewCell*)sender.superview;
// You can signal the cell to select itself (will not send the delegate message)
[customCell setSelected:YES animated:NO];
// Alternately this can be done but I don't recommend
NSIndexPath *indexPath = [myTableView indexPathForCell:customCell];
if ( myTableView.delegate && [myTableView.delegate respondsToSelector:#selector(tableView:willSelectRowAtIndexPath:)] ) {
[myTableView.delegate tableView:myTableView willSelectRowAtIndexPath:indexPath];
}
}

How can I disable the UITableView selection?

When you tap a row in a UITableView, the row is highlighted and selected. Is it possible to disable this so tapping a row does nothing?

All you have to do is set the selection style on the UITableViewCell instance using either:
Objective-C:
cell.selectionStyle = UITableViewCellSelectionStyleNone;
or
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
Swift 2:
cell.selectionStyle = UITableViewCellSelectionStyle.None
Swift 3 and 4.x:
cell.selectionStyle = .none
Further, make sure you either don't implement -tableView:didSelectRowAtIndexPath: in your table view delegate or explicitly exclude the cells you want to have no action if you do implement it.
More info here and here

For me, the following worked fine:
tableView.allowsSelection = false
This means didSelectRowAt# simply won't work. That is to say, touching a row of the table, as such, will do absolutely nothing. (And hence, obviously, there will never be a selected-animation.)
(Note that if, on the cells, you have UIButton or any other controls, of course those controls will still work. Any controls you happen to have on the table cell, are totally unrelated to UITableView's ability to allow you to "select a row" using didSelectRowAt#.)
Another point to note is that: This doesn't work when the UITableView is in editing mode. To restrict cell selection in editing mode use the code as below:
tableView.allowsSelectionDuringEditing = false

Because I've read this post recently and it has helped me, I wanted to post another answer to consolidate all of the answers (for posterity).
So, there are actually 5 different answers depending on your desired logic and/or result:
1.To disable the blue highlighting without changing any other interaction of the cell:
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
I use this when I have a UIButton - or some other control(s) - hosted in a UITableViewCell and I want the user to be able to interact with the controls but not the cell itself.
NOTE: As Tony Million noted above, this does NOT prevent tableView:didSelectRowAtIndexPath:. I get around this by simple "if" statements, most often testing for the section and avoiding action for a particular section.
Another way I thought of to test for the tapping of a cell like this is:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
// A case was selected, so push into the CaseDetailViewController
UITableViewCell *cell = [tableView cellForRowAtIndexPath:indexPath];
if (cell.selectionStyle != UITableViewCellSelectionStyleNone) {
// Handle tap code here
}
}
2.To do this for an entire table, you can apply the above solution to each cell in the table, but you can also do this:
[tableView setAllowsSelection:NO];
In my testing, this still allows controls inside the UITableViewCell to be interactive.
3.To make a cell "read-only", you can simply do this:
[cell setUserInteractionEnabled:NO];
4.To make an entire table "read-only"
[tableView setUserInteractionEnabled:NO];
5.To determine on-the-fly whether to highlight a cell (which according to this answer implicitly includes selection), you can implement the following UITableViewDelegate protocol method:
- (BOOL)tableView:(UITableView *)tableView
shouldHighlightRowAtIndexPath:(NSIndexPath *)indexPath

To sum up what I believe are the correct answers based on my own experience in implementing this:
If you want to disable selection for just some of the cells, use:
cell.userInteractionEnabled = NO;
As well as preventing selection, this also stops tableView:didSelectRowAtIndexPath: being called for the cells that have it set. (Credit goes to Tony Million for this answer, thanks!)
If you have buttons in your cells that need to be clicked, you need to instead:
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
and you also need to ignore any clicks on the cell in - (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath.
If you want to disable selection for the whole table, use:
tableView.allowsSelection = NO;
(Credit to Paulo De Barros, thanks!)

As of iOS 6.0, UITableViewDelegate has tableView:shouldHighlightRowAtIndexPath:. (Read about it in the iOS Documentation.)
This method lets you mark specific rows as unhighlightable (and implicitly, unselectable) without having to change a cell's selection style, messing with the cell's event handling with userInteractionEnabled = NO, or any other techniques documented here.

You can also disable selection of row from interface builder itself by choosing NoSelection from the selection option(of UITableView Properties) in inspector pane as shown in the below image

FIXED SOLUTION FOR SWIFT 3
cell.selectionStyle = .none

In your UITableViewCell's XIB in Attribute Inspector set value of Selection to None.

EDIT: for newer Swift it is changed to:
cell.selectionStyle = .none
See this for more info:
https://developer.apple.com/documentation/uikit/uitableviewcell/selectionstyle
In case anyone needs answer for Swift:
cell.selectionStyle = .None

If you want selection to only flash, not remain in the selected state, you can call, in
didSelectRowAtIndexPath
the following
[tableView deselectRowAtIndexPath:indexPath animated:YES];
so it will flash the selected state and revert.

From the UITableViewDelegate Protocol you can use the method willSelectRowAtIndexPath
and return nil if you don't want the row selected.
In the same way the you can use the willDeselectRowAtIndexPath method and return nil if you don't want the row to deselect.

This is what I use ,in cellForRowAtIndexPath write this code.:
cell.selectionStyle = UITableViewCellSelectionStyleNone;

1- All you have to do is set the selection style on the UITableViewCell instance using either:
Objective-C:
cell.selectionStyle = UITableViewCellSelectionStyleNone;
or
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
Swift 2:
cell.selectionStyle = UITableViewCellSelectionStyle.None
Swift 3:
cell.selectionStyle = .none
2 - Don't implement -tableView:didSelectRowAtIndexPath: in your table view delegate or explicitly exclude the cells you want to have no action if you do implement it.
3 - Further,You can also do it from the storyboard. Click the table view cell and in the attributes inspector under Table View Cell, change the drop down next to Selection to None.
4 - You can disable table cell highlight using below code in (iOS) Xcode 9 , Swift 4.0
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "OpenTbCell") as! OpenTbCell
cell.selectionStyle = .none
return cell
}

Objective-C:
Below snippet disable highlighting but it also disable the call to didSelectRowAtIndexPath. So if you are not implementing didSelectRowAtIndexPath then use below method. This should be added when you are creating the table. This will work on buttons and UITextField inside the cell though.
self.tableView.allowsSelection = NO;
Below snippet disable highlighting and it doesn't disable the call to didSelectRowAtIndexPath. Set the selection style of cell to None in cellForRowAtIndexPath
cell.selectionStyle = UITableViewCellSelectionStyleNone;
Below snippet disable everything on the cell. This will disable the interaction to buttons, textfields:
self.tableView.userInteractionEnabled = false;
Swift:
Below are the Swift equivalent of above Objective-C solutions:
Replacement of First Solution
self.tableView.allowsSelection = false
Replacement of Second Solution
cell?.selectionStyle = UITableViewCellSelectionStyle.None
Replacement of Third Solution
self.tableView.userInteractionEnabled = false

Try to type:
cell.selected = NO;
It will deselect your row when needed.
In Swift3 ...
override func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
let r = indexPath.row
print("clicked .. \(r)")
tableView.cellForRow(at: indexPath)?.setSelected(false, animated: true)
}

Swift 3,4 and 5
Better practice, write code in UITableViewCell
For example, you have UITableViewCell with the name MyCell,
In awakeFromNib just write self.selectionStyle = .none
Full example:
class MyCell: UITableViewCell {
override func awakeFromNib() {
super.awakeFromNib()
self.selectionStyle = .none
}
}

I've been battling with this quite profusely too, having a control in my UITableViewCell prohibited the use of userInteractionEnabled property. I have a 3 cell static table for settings, 2 with dates, 1 with an on/off switch. After playing about in Storyboard/IB i've managed to make the bottom one non-selectable, but when you tap it the selection from one of the top rows disappears. Here is a WIP image of my settings UITableView:
If you tap the 3rd row nothing at all happens, the selection will stay on the second row. The functionality is practically a copy of Apple's Calendar app's add event time selection screen.
The code is surprisingly compatible, all the way down to IOS2 =/:
- (NSIndexPath *)tableView: (UITableView *)tableView willSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if (indexPath.row == 2) {
return nil;
}
return indexPath;
}
This works in conjunction with setting the selection style to none, so the cell doesn't flicker on touch down events

We can write code like
cell.selectionStyle = UITableViewCellSelectionStyleNone;
but when we have custom cell xib above line give warning at that time for
custom cell xib
we need to set selection style None from the interface builder

You just have to put this code into cellForRowAtIndexPath
To disable the cell's selection property:(While tapping the cell).
cell.selectionStyle = UITableViewCellSelectionStyle.None

From UITableViewDataSource Protocol, inside method cellForRowAt add:
let cell = tableView.dequeueReusableCell(withIdentifier: "YOUR_CELL_IDENTIFIER", for: indexPath)
cell.selectionStyle = .none
return cell
OR
You can goto Storyboard > Select Cell > Identity Inspector > Selection and select none from dropdown.

I am using this, which works for me.
cell?.selectionStyle = UITableViewCellSelectionStyle.None

try this
cell.selectionStyle = UITableViewCellSelectionStyleNone;
and
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];
and you can also set selection style using interfacebuilder.

Directly disable highlighting of TableViewCell into storyboard

While this is the best and easiest solution to prevent a row from showing the highlight during selection
cell.selectionStyle = UITableViewCellSelectionStyleNone;
I'd like to also suggest that it's occasionally useful to briefly show that the row has been selected and then turning it off. This alerts the users with a confirmation of what they intended to select:
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
[tableView deselectRowAtIndexPath:indexPath animated:NO];
...
}

To disable the highlighting of the UItableviewcell
cell.selectionStyle = UITableViewCellSelectionStyleNone;
And should not allow the user to interact with the cell.
cell.userInteractionEnabled = NO;

You Can also set the background color to Clear to achieve the same effect as UITableViewCellSelectionStyleNone, in case you don't want to/ can't use UITableViewCellSelectionStyleNone.
You would use code like the following:
UIView *backgroundColorView = [[UIView alloc] init];
backgroundColorView.backgroundColor = [UIColor clearColor];
backgroundColorView.layer.masksToBounds = YES;
[cell setSelectedBackgroundView: backgroundColorView];
This may degrade your performance as your adding an extra colored view to each cell.

You can also do it from the storyboard. Click the table view cell and in the attributes inspector under Table View Cell, change the drop down next to Selection to None.

You can use :
cell.selectionStyle = UITableViewCellSelectionStyleNone;
in the cell for row at index path method of your UITableView.
Also you can use :
[tableView deselectRowAtIndexPath:indexPath animated:NO];
in the tableview didselectrowatindexpath method.

You can use this
cell.selectionStyle = UITableViewCellSelectionStyleNone;

You can use ....
[cell setSelectionStyle:UITableViewCellSelectionStyleNone];

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