Detect tap outside tableview cells to perform action - ios

Question

I am new to iOS development, i've been following apple intro to iOS and implemented the to-do list app.
I have tableview that shows the list of the current to-do list, and another view controller that allows the user to add a new item in a textfield then add to the list.
I have a little + on top of my tableview that performs a segue action to the add to-do item view.
I want to be able to perform the same action if the user taps on an empty cell
I tried to put this code in and it works but I want to put it in the right position so it only triggers when the user hits empty space in the table:
[self performSegueWithIdentifier:#"showAddItem" sender:self];
Thank you.
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = #"ListPrototypeCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];
// Configure the cell...
ABCTodoItem *toDoItem = [self.toDoItems objectAtIndex:indexPath.row];
cell.textLabel.text = toDoItem.itemName;
if (toDoItem.completed) {
cell.accessoryType = UITableViewCellAccessoryCheckmark;
}
else
{
cell.accessoryType = UITableViewCellAccessoryNone;
}
return cell;
}

Answer 1

In my opinion this solution is the cleanest:
Add a tap gesture to your UITableView's backgroundView. If the backgroundView is nil, add a transparent UIView, and add a gesture to it.
Now hook up your action to this gesture recognizer.

Answer 2

I can see at least two solutions here.
Solution 1. Adding en empty cell by modifying the data source
After you have populated your toDoItems add this:
[self.toDoItems addObject:#""];
Notice that toDoItems should be type of NSMutableArray.
Now let's handle creating cells:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = #"ListPrototypeCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];
NSObject *objItem = [self.toDoItems objectAtIndex:indexPath.row];
if([objItem isKindOfClass: [ABCTodoItem class]]) {
ABCTodoItem *toDoItem = (ABCTodoItem*) objItem;
cell.textLabel.text = toDoItem.itemName;
}
else if([objItem isKindOfClass: [NSString class]]) {
NSString *item = (NSString*) objItem;
cell.textLabel.text = item;
}
return cell;
}
Touch action:
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
NSObject *objItem = [self.toDoItems objectAtIndex:indexPath.row];
if([objItem isKindOfClass: [ABCTodoItem class]]) {
ABCTodoItem *toDoItem = (ABCTodoItem*) objItem;
// Open your toDoItem
}
else if([objItem isKindOfClass: [NSString class]]) {
self performSegueWithIdentifier:#"showAddItem" sender:self];
}
}
Solution 2. Adding an empty cell without modifying the data source
This makes it possible to create one extra cell:
- (NSInteger)numberOfRowsInSection:(NSInteger)section {
return [self.toDoItems count] + 1;
}
Now again let's handle creating cells:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
static NSString *cellIdentifier = #"ListPrototypeCell";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];
if([indexPath.row < [self.toDoItems count]) {
NSObject *objItem = [self.toDoItems objectAtIndex:indexPath.row];
if([objItem isKindOfClass: [ABCTodoItem class]]) {
ABCTodoItem *toDoItem = (ABCTodoItem*) objItem;
cell.textLabel.text = toDoItem.itemName;
}
}
else {
cell.textLabel.text = #"";
}
return cell;
}
And then handling the touch action:
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
if([indexPath.row < [self.toDoItems count]) {
NSObject *objItem = [self.toDoItems objectAtIndex:indexPath.row];
if([objItem isKindOfClass: [ABCTodoItem class]]) {
ABCTodoItem *toDoItem = (ABCTodoItem*) objItem;
// Open your toDoItem
}
}
else {
self performSegueWithIdentifier:#"showAddItem" sender:self];
}
}

Answer 3

I hope I have understood your question correctly; correct me if I am wrong. You have a to-do List populated in a TableViewController which has some tasks and one (or more) empty cells. When you click on these cells, you would want to call [self performSegueWithIdentifier:#"showAddItem" sender:self]; a method that presents a ViewController that allows you to add more items into the list.
Once you have populated your TableViewController in such a way that you have an empty cell, you can always get the NSIndexPath of the empty cell.
When you tap on a cell, a method will be called, called: (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath. As you can see, you will get the index information of the tapped cell. There, you can add the code like so:
-(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {
//Add your logic for the rest of the items
//If you have 7 items in the to-do list, you would have 8 cell,
//the eight one being empty. If indexPath.row is equal to 8 then,
//it says that it MUST be the last item, that is empty
if(indexPath.row == self.itemsInTheList.count) {
[self performSegueWithIdentifier:#"showAddItem" sender:self];
}
}
Alternatively, you can set the tag property of the cell; and that's the story for a different day.