In a UIViewController there is a UITableView which consists custom UITableViewCell with a UIButton.
When the user clicks the button (in the custom UITableViewCell), I want to display a message in the hosting UIViewController - what is the right way to achieve that? How should I notify the UIViewController that the button was clicked?
You should use delegation to tell the UIViewController that something happened in the cell.
I'm not exactly sure what kind of message you are referring to but if you mean a you want to show a popup just create a UIAlertView and show it when the button is clicked in the cell.
However, if you mean change a UIlabel text or whatever as a message on the ViewController you can always pass whatever you need to change into the TableView and Cell or the UIViewController itself into it.
I usually create a method on the custom cells class and pass it whatever I need into the custom TableView's constructor. Then in the TableView's GetCell() method pass whatever I need to change into that method I created on the cell and save it as a variable on the cell.
If you've initiated your UITableViewCell, and added a button to the cell, you can use a Delegate when the button is clicked, something like this:
UIButton button = new UIButton (cell.Bounds.X, cell.Bounds.y, cell.Bounds.Width, cell.Bounds.Height);
button.TouchUpInside += (object sender, EventArgs e) =>
{
label.text = "Blablabla";
};
Where the label is, is up to you. I hope this helps, good luck!
Related
I'm having a TableView. In that tableView, I custom it's cells
like this
In this cell I have 2 part. An Image and an TextField.
It's look like facebook's post status. When I click to Image, I want to open a new ViewController and the same for TextField
But I have a problem that I can't call segue from my cell's class file.
Are there any way that I can call a function in TableViewController's class from TableViewCell's class ?
I know that I can use delegate but I don't like this way a lot, because if I do this way I have to set a lot of delegate in my project.
Are there any better way to present a new ViewController directly from TableViewCell's class
Using a delegate is a very good way to solve your problem.
If you don't like that solution then you could design a table view cell that has a closure property set by the view controller, and invokes that closure when the button is pressed.
EDIT:
Another alternative is to leave the button action empty in your custom cell, but still connect up outlets to the buttons.
Then in your cellForRow(at:) method, install an IBAction that has your view controller as the target. (Credit to #SoanSani, who's answer is below)
In that IBAction method, you can use the coordinates of the button to figure out the indexPath of the cell hat contains the button that was tapped.
I've created an extension to UITableView that lets you figure out the cell that contains any view. The code is below:
import UIKit
public extension UITableView {
/**
This method returns the indexPath of the cell that contains the specified view
- Parameter view: The view to find.
- Returns: The indexPath of the cell containing the view, or nil if it can't be found
*/
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
}
}
You can use delegates, but if you dont want to use delegates
while setting up the cell add target to your button tableViewController class and then you can receive all events in tableview class rather than cell class.
But this would require to add tags which you can use to differentiate which button in cell was clicked
Objective C Code
[OkBtn addTarget:self action:#selector(okButtonTapped:) forControlEvents:UIControlEventTouchUpInside];
Swift Code
OkBtn.addTarget(self, action: #selector(ViewController.okButtonTapped), for: .TouchUpInside)
I want to replace the default keyboard of a UITextField with a custom keyboard. So I created a new subclass of a UIViewController with a xib-file (the other way like creating both files seperately and setting the File's Owner doesn't work either).
Then I added a button to the KeyboardView and connected it to an IBAction. After that I set the textfields inputView to the new view like this:
override func viewDidLoad() {
let keyboardVC = KeyboardViewController()
textField.inputView = keyboardVC.view
keyboardVC.view.autoresizingMask = .FlexibleHeight
keyboardVC.delegate = textField
}
It's working and the custom keyboard shows up, but if I touch the button, the IBAction is not called. What's the problem in my setup? (I checked some examples and they all do it the same way).
UPDATE:
I now removed the ViewController and subclassed the UIView. Now the actions are working. Why isn't it working with a ViewController?
Since no one holds the UIViewController- there is no reference to it after the viewDidLoad() ended, it is released from the memory.
When the button is pressed, the view controller that should response to the action is not exist -> you are holding only the view of the view controller as the textField.inputView.
The headline seems lengthy but what I'm trying to do is quite simple.
I have a couple of identical buttons lined in a row and set their tags to 0...n. Clicking on any of them (the 2nd for example) would bring up a popover view in which there are several buttons representing different options (A, B, C, D). What I want to do is to turn the 2nd Button's title to B if we click on option B.
The problem is that the popover view does not know which Button presented it, since all popoverViews are instances of the same UIViewController class. So I am thinking of distinguishing the n buttons by setting their tags to different values. However, I don't know how to get the UIButton's tag from a button inside the popover this UIButton presented.
Many thanks in advance!
This is how I will solve this in swift. I will declare a delegate in the popoverViewController and have a method e.g
protocol popOverViewControllerDelegate: class {
func popOverViewController(controller: PopOverViewController,
didSelectItem buttonTitle: String)
}
then I will add a target action to the UIButton in the popOver
button.addTarget(self, action: "selected:",forControlEvents:.TouchUpInside)
the select method will have sender passed to it
func selected(sender:UIButton){
delegate?.popOverViewController(self, didSelectItem: sender.currentTitle)
//dismiss viewcontroller
}
remember to declare
weak var delegate: popOverViewControllerDelegate!
now have the viewcontroller that called the popOver, subclass to this delegate and implement it's method. Whenever a button in the popOver is selected, this method will be called and the currentTitle of the method will be passed. You can now use that to set the currentTitle of the button that called the popOver.
In case you need further help with the last part, please ask.
I've fixed the problem by adding a property tagNumberso that after instantiating the popoverViewController's class, I set the instance's tagNumber to the sender's tag. Then I send the tagNumber back together with sender.currentTitle. This way, the presenter of the popover could know both the title and tag number of the UIButton.
I can't seem to handle a button click properly inside a custom UITableViewCell. It's a cell that contains a label and a button. I have the following code:
var cell = tableView.DequeueReusableCell (cellKey) as ApptHistoryCell;
if (cell == null)
{
cell = _container.Cell;
cell.SelectionStyle = UITableViewCellSelectionStyle.None;
}
if (InfoClicked != null)
{
cell.ActionButton.TouchUpInside += InfoClicked;
}
InfoClicked is an event handler passed on in loop on cell creation. When the cell is re-used, this causes a null reference exception, because (I think) TouchUpInside is trying to call 2 handlers. Old one and the new one, which causes a crash. If I put the event handler inside cell == null if block, then the wrong action is shown.
How can I handle the click properly?
Thanks!
The way I handle buttons inside custom cells:
I define an IBAction that I connect to a UIButton event inside the custom cell
I define a delegate and a delegate method for the cell to handle the button action
The IBAction calls that delegate method
When defining your cells in cellAtRow... I set the tableViewController to be the delegate. cell.delegate=self;
I do whatever action I would like to do inside that delegate method in the tableViewController
Makes sense?
you should create your cell from a xib file, which already connects the buttons to the owner's targets (the view controller).
In your custom cell just locate your button at IB and make connection with the property.
Now, in the controller at cellForRowAtIndexPath, what you need, just tag that button, say:
(MyCustomCell*)cell.myButton = indexPath.row;
Now, after that just set the click event like that:-
[(MyCustomCell*)cell.myButton addTarget:self action:#selector(NeedFunctionToCall:) forControlEvents:UIControlEventTouchUpInside];
Now, at same view controller, implement that required method, like that:
-(void)NeedFunctionToCall:(id)sender
{
NSLog("Got the event :-> %d, from the cell/button",[sender tag]);
}
I have a 'Load More' UIButton inside a custom UITableViewCell. My table also uses a Delegate. I want to reload the table data when this button is clicked. I have noticed that when I click the button, nothing happens. But when I click on the area around the button i.e. the actual Cell, the Delegate gets the RowSelected event.
I tried using SetSelected(true,false); from the button's touch up inside event to see if it would fire the RowSelected event for the delegate, but it didn't.
Can anyone explain me how I can make a button click for a Custom Table cell fire the actual Row Selected event? If this isn't a viable option, is there a better way to 'Load more data' other than placing the button inside a custom table view cell?
Thanks!
UPDATE:
I do use ContentView.AddSubView as shown in the code below. Please note I'm using Monotouch, but the logic is the same:
public LoadMoreCell (string reuseCellIdentifier)
:base(UITableViewCellStyle.Default, reuseCellIdentifier)
{
SelectionStyle = UITableViewCellSelectionStyle.None;
_btnLoadMore = UIButton.FromType(UIButtonType.RoundedRect);
_btnLoadMore.Frame = new RectangleF(10,5,300,30);
_btnLoadMore.SetTitle("Load More", UIControlState.Normal);
_btnLoadMore.UserInteractionEnabled = true;
ContentView.AddSubview(_btnLoadMore);
}
I have a TableDelegate that has a RowSelected method where I reload the data...however, the RowSelected only gets fired when I click the actual row.
I think you might have added the uibutton as
[self addSubView:yourButton];
instead use :-
[self.contentView addSubview:yourButton];
and all the other controls of your custom cell.
Do this in the initializer of your custom cell :-
- (id)initWithStyle:(UITableViewCellStyle)style reuseIdentifier:(NSString *)reuseIdentifier {}
make a custom UITableViewDataSource for your table
and when you hit the button 'Load more', call a method of this datasource to add other data to the list of the datasource, add this datasource to your table and make sure to reload the data of the table
this.tblData.ReloadData ();