I am looking for some pointers on how to implement binding for a single click (similar to what NSTableView already has for Double Click on a row). Initially I thought, it is much simpler to leverage selectionIndexes property and make use of that. However when the table view gets loaded the value of this property corresponds to the zeroth index(first row) and it makes to think that the first row is always selected. Please note that I do not want to use the option of setting delegate/datasource for the tableview and use the available methods there.
Related
I am drawing a tableview via BehaviorRelay.
Currently, I am using the code below as a way to add data.
viewModel.user.append(Person(name: "king", phoneNumber: "12341234"))
viewModel.personObservable.accept(viewModel.user)
I wonder if this code changes the user itself so that the whole tableView is redrawn.
If so, what method can I use to change only the data I added?
The code presented causes the personObservable (which is actually a BehaviorRelay apparently,) to emit a next event that contains an entire array of Person values, not just the latest Person added. Importantly, it's not emitting the viewModel.user object (at least not conceptually) but an entirely different object that happens to be equal to viewModel.user.
The default dataSource, the one that you get when you call items with anything other than a DataSource object, will call reloadData on the table view. This doesn't cause "the whole tableView" to be redrawn though, but it will cause the table view to query the data source for all of the visible cells, even if they haven't changed.
If you only want the table view to load the new cell, then the data source object needs to be smart enough to compare the new array with the array it's currently displaying so it can figure out which values are different and add/remove/move cells as appropriate, instead of just calling reloadData. As #Sweeper said in the comments, the RxDataSources library contains a set of data source classes that have that logic built in. If you wanted to reinvent the wheel, just write a class that conforms to both RxTableViewDataSourceType & UITableViewDataSource and implement the diffing yourself.
I would like to remove the top left back button.
I tried to check "Full screen" option, but the arrow is still here.
I want to remove the back button because I have a button next to this button, and I don't want the user tap on it by mistake
Thx
According to the Apple Documentation the deprecated method that was in the previous answer (which used to solve this issue) has been replaced with:
reloadRootPageControllers(withNames names: [String],
contexts: [Any]?,
orientation: WKPageOrientation,
pageIndex: Int)
"Parameters
names
An array of NSString objects, each of which contains the identifier of an interface controller in your storyboard file. The order of the identifiers in the array defines the order of the corresponding interface controllers in the page-based interface.
contexts
An array of objects of type id. Use this parameter to pass context objects to each of the interface controllers loaded into the page-based interface. The first object in the array is passed to the first interface controller, the second object is passed to the second interface controller, and so on.
orientation
The scrolling orientation for the page-based interface. For a list of valid values, see WKPageOrientation."
And pageIndex should be pretty simple to figure out. If you only have one element in [names] it will be 0. Otherwise you should select the index of the page you want loaded from [names]
Try:
WKInterfaceController.reloadRootControllersWithNames(["myInterfaceController"], contexts: [])
This removes it by making the controller the root controller. You may have to reload the controller after calling this.
I have three elements in my UICollectionViewCell:
Two labels with name and price, and a quantity button.
I would like to add the name and the quantity with "didSelectItemAtIndexPath" to a specific collection view in the previous view controller and the price in another view controller. I may achieve this by using a segue to pass data to any view controller of my choice.
Also, at the same time, I want to keep track of the selections I make adding them to a table view below the collection view.
My guess is to create empty arrays for each item.. one for name, price and quantity.
I may be wrong.. and I tried to append my current selection and I know I am missing something.
To pass information to a previous viewController use a delegate protocol. Suppose a is your first viewController, and b is your second viewController.
You can create a delegate protocol in b (here you specify a func you want to execute inside of a)
Set a as the delegate for b
write a function yourDelegateFunction in a , which your delegate protocol will call to update the viewController with your first collection.
in didSelectItemAtIndexPath call delegate.yourDelegateFunction
Here's a video with an easy guide for how this works:
https://www.youtube.com/watch?v=3BcBu30thIA
If you provide a sample of your code, and highlight where you experienced issues, I can provide a more precise solution.
I have a TreeTableView that is working great. I have implemented a context menu that appears when the "TreeTableCell" is clicked. In my context menu, I have a MenuItem called "edit" that, when selected, I want to cause the current TreeTableCell to start editing. Unfortunately, I am unable to figure out how to correctly start editing the cell.
My initial thinking was that since the context menu callback is in the scope of my TreeTableCell instance, I would call the "startEdit" method of my cell. This appears to work ... however, when the commitEdit occurs, I get a NullPointerException deep within the internals of JavaFX. This makes me think that explicitly calling startEdit() is the wrong thinking and that there should be a correct way to cause a specific cell in the table to begin its edit cycle.
I was able to find the answer after lower level study. I had assumed that I could call startEdit() against my TreeTableCell however that is not the correct way to flag a table cell as entering is editing mode.
Instead both TableView and TreeTableView expose an edit() method that take two parameters:
The row number of the table indexed from 0
The TableColumn of the table
The combination of row and column provide a unique location of a cell in the table. Calling edit() places the cell in editing mode.
Here is the JavaDoc for TableView edit method:
JavaDoc for TableView edit
I'm trying to set up a view-based table in Swift using bindings. All of the examples I've seen use a datasource/delegate setup.
I have an array of Flag objects which has two properties - flagName: String and flagImage: NSImage. I have an NSArrayController managing this array.
If I set up a cell-based table, and bind one column to arrangedObjects.flagImage and the other to arrangedObjects.flagName, I get a table displaying images and names, and I can use the array controller's add and remove methods, so there are no problems with my datasource or my array controller.
I have been following the instructions in Apple's TableView Programming Guide to bind my view-based table to my array controller:
tableView Content binding: FlagController.arrangedObjects
textField Value binding: TableCellView.objectValue.flagName
imageView Value binding: TableCellView.objectValue.flagImage
(IBs autocomplete is not happy with the paths for objectValue.flagName respectively flagImage; it doesn't feel that there should be any completion whatsoever and says it can't resolve the path, so it looks as if the problem is with the tableView's content.)
If I do this, my table has a number of rows that corresponds to the number of elements that my array controller is managing at that moment (I have two simple setups, one object vs. 50 objects, so it's clear that something is bound). What I don't get is a display; and selecting a table row does not seem to send back a message to my flagController.
What am I missing? Has anyone been able to make this work? I've had no problems with other bindings in Swift so far, but I'm starting to think that the sudden reappearance of datasource examples is not unrelated to this.
It sounds like you've failed to implement the delegate method -tableView:viewForTableColumn:row:. That's a common cause of blank tables.
You don't actually have to implement that if you make sure the identifier of the table column and the identifier of the table cell view are the same in IB.
Otherwise, the method can just do this:
- (NSView*) tableView:(NSTableView*)tableView viewForTableColumn:(NSTableColumn*)tableColumn row:(NSInteger)row
{
return [tableView makeViewWithIdentifier:#"TheIdentifierOfYourTableCellView" owner:self];
}
(It could also do more, if desired.)