如何从UItableviewcell呈现viewcontroller

Question

I am trying to follow the MVC model in developing my iOS app and have an issue here: how do I fire a viewcontroller from a tableviewcell, instead of its parent tableviewcontroller. PresentViewController can only be invoked from a viewcontroller.

Here is the situation:

• I have a data object at the backend myDataObject;

• I also have a tableview where I populated a type of table view cell, myDataCell, with an instance of MyDataObject;

• Now, I would like to programmatically (instead of segue) trigger another ViewController from a UIButton click event in myDataCell.

My goal is to decouple the MVC as much as possible, by trying to avoid having each object keeping pointers to the other two involved, for example, I do not want the cell to keep reference of MyDataObject, nor do I want it to keep reference of its tableviewcontroller.

Here are several scenarios of how to handle this situation, and the challenges:

1. declare myDataCellDelegate and myDataObjectDelegate, implement methods from both delegate declarations in the tableviewcontroller, and set a reference of the tableviewcontroller and myDataCell in the delegate. This way myDataObject has a reference to the tableviewcontroller and myDataCell.

Question here is how do I invoke handleButtonTouched event from myDataCell, and still be able to present the next viewcontroller, without accessing myDataObject from myDataCell? Or do I have to keep a reference of myDataObject in myDataCell? I already have a reference of myDataCell in myDataObject from the delegate method above.

2. declare myDataObjectDelegate only, and implement the delegate methods in the tableviewcontroller. I can set the reference of the tableviewcontroller and myDataCell in the delegate. This way myDataCell does not have to have reference to its parent viewcontroller, only myDataObject has reference to both.

With this approach, I can do myDataObject->tableviewcontroller->presentviewcontroller. But how do I make the myDataCell->buttonclick event as the trigger? I still need to pass the info from myDataObject to myDataCell.

Thanks guys.

EDIT:

I forgot to mention that my goal of going through such trouble is that I intend to keep myDataCell and myDataObject in a framework.

Answer 1

Why are you opposed to using the normal UITableViewDelegate & UITableViewDataSource methods? They do an excellent job of adhering to MVC.

I always have a view controller that acts as the delegate and data source for the table view. In the view controller I make a request to a data manager (essentially a controller that handles interaction with the model layer) that will return some collection of data. I keep that data (typically an NSArray ) as a property in the view controller and reload the table view.

I then implement -tableView:didSelectRowAtIndexPath: . There I can see which cell was selected, which data object is associated with that cell (without having the cell itself keep a reference to the data), and handle any transition I need to at that point. This follows MVC because the view doesn't know anything about the data.

Answer 2

I think you are over-analysing a little. Check out this Apple document which explains the MVC design pattern. Key is that the views should not reference the model, nor vice versa. The controller acts as the go-between.

Answer 3

Subclassing UITableViewCell is a way to follow MVC.

I'm going to explain my approach of following MVC if i have a scenario like above.

Approach:

I figure out two problems from above explanations -

1. Where to define buttonTapped events

2. Maintain TableViewController object in cell

Correct me if i'm misguide or missing something.

First thing - handleButtonTouched:

Create button object in .h file of your custom cell, and add it's target method in cellForRowAtIndexPath of your TableViewController , So that you can get your selector from TableViewController itself.

Second thing - How to fire presentViewController event from cell

Create one more variable of UIViewController assign it in cellForRowAtIndexPath method. Now from cell you can present your viewController using this object.

Give a comment if not clear.

Answer 4

Update:

• implemented a manager to link the view controller and myDataObject;

• added gesture recognizer on myCell

Answer 5

A cell is a view in the MVC. The controller must do the logic, it's the intermediate. In that case I always created a custom delegate, something like UItableviewcellDelegate with something like showThisVC:(UITableViewCell)cell and you can get the row number easily because you know the cell in the controller.