Gtk treeview problems - gtk

I have a simple treeview (like this one - http://www.mono-project.com/GtkSharp_TreeView_Tutorial) filled with 200 items and connected to scrollbar. Everything works, but when I select an item and use arrow keys, selected item can be out of visible area. Is it possible to focus on it or set adjustment of scrollbar, i.e.
void HandleTreeSelectionChanged (object sender, EventArgs e)
{
vadjustment.Value=SELECTED-ITEM.DISTANCE-FROM-TOP-OF-TREEVIEW;
}
And one more question: How to paint a black border to table (this tree.EnableGridLines = TreeViewGridLines.Both; makes just inside grid).
Thanks in advance.
Matej

I agree with Johannes' answer that you seem to be doing something odd, you really should just need to use a GtkScrolledWindow. It should handle keyboard navigation (what you seem to be describing in your comment to Johannes' answer) too, this is not something you should need to be doing manually.
To anyway try to answer your question, you can cause the tree view to scroll to any given cell using gtk_tree_view_scroll_to_cell().

To add scroll bars to a tree view (or text view), you just need to add it to a GtkScrolledWindow; it handles everything automatically. I'm pretty sure it also creates a border in most themes.
Update: Alternatively, you can also "bind" the tree view's scrolling behaviour to an arbitrary scrollbar by setting the scrollbar's adjustment to that of the tree view:
scrollbar = gtk.VScrollbar(treeview.props.vadjustment)
(Oh, that's the PyGTK syntax; in Gtk# it's probably treeview.VAdjustment.)

Related

Available height to position UI elements assuming keyboard always shows

I am encountering a problem that I'm not sure how to solve. If you look at the screenshot below, you'll see that the UI is laid out so that it neatly fits into the space between the safe area layout guide's top anchor and the top of the keyboard.
The keyboard will ALWAYS be shown in this view controller. But I need a way of knowing what the height of the keyboard is so that I can do some math to figure out how to tall to make the UITextView (the red box).
I tried the approach of registering for notifications on when the keyboard will show, but that is too late.
I need a way of knowing the height of the keyboard before the view renders so that I can configure the height of each of the elements in the UI.
Is there a way to do this?
Thank you!
One option would be to capture the dimensions of the Keyboard when it IS presented then pass those dimensions into this view.
However, you will also want to make sure that you are handling cases such as the split keyboard on an iPad and things of that nature.
For that you might choose to look at the documentation on using the keyboardLayoutGuide and use it with some constraints.
https://developer.apple.com/documentation/uikit/keyboards_and_input/adjusting_your_layout_with_keyboard_layout_guide

Keep cursor position on bottom line in textView Swift

I need to create a UI where, as the user types, the cursor/typing area stays in the middle of the page and the newly typed text is pushed 'up and off' the top of the page.
I've tried to set the cursor position to the bottom of a text view which covers 0.6 of the superview but that doesn't work (presumably because it doesn't have any text?). This is a great answer for general cursor placement but my use case isn't catered for.
The code I used to try place the cursor at the end of the text view is :
func setCursorPosition() {
let newPosition = textViewOutlet.endOfDocument
textViewOutlet.selectedTextRange = textViewOutlet.textRange(from: newPosition, to: newPosition)
}
This doesn't work because it is looking for filled in text but sometimes the text view would be empty and I'd still need to load it on the bottom line.
The effect I'm trying to create would look like this :
quite a complex problem I think - any ideas?
For people who have this problem in future. I solved this by coming at it from a different angle. Rather than attempting to place the cursor half way down the page, I removed the height constraints and made the text view dynamically resize based on the content.
Then I adjusted the constraints (helped by this answer) to fix the space to the bottom safe area but didn't specify a height.
This way, the text view dynamically resizes but in an upwards direction. When it reaches the gradient I have placed over the frame it starts to fade out.
Perfect (I also disabled scrolling to make this work)
Top tip - if something seems really hard there might be a different way to approach the problem!

NSOutlineView disclosure triangle vertically off center

I'm working with an NSOutlineView on a macOS app and it provides disclosure triangles for items that can be expanded.
I'm also creating custom NSTableCellView items rather than using basic cell items. This allows me to create the cell how I want visually.
My issue is that when they're displayed, the disclosure triangle on the left is not centered vertically.
Notice how the disclosure triangles are not aligned properly. They're a bit lower than they should be. If you scroll away and come back, sometimes, they automatically align themselves correctly. Has anyone been able to fix this issue before?
For what it's worth, I'm using the following code as well for the cells.
self.outlineView.rowHeight = CGFloat(integerLiteral: 66)
self.outlineView.usesAutomaticRowHeights = true
It's hard to figure out what the problem is without seeing how you've set up your project, but I'm going to give it shot.
First, when usesAutomaticRowHeights is set to true, the outline view uses Auto Layout to position the cell views. Thus, you need to be utilizing constraints in your Storyboard or Nib file, or things will behave strangely (see: your picture). If I had to guess, the prototype cell view you set up in Interface Builder is having its autoresizingMask translated into Auto Layout constraints (which, generally, causes a boatload of problems).
What I would do is this:
Open up the Storyboard or Nib document containing the outline view.
Locate the prototype NSTableCellView instance that contains the street name text field in the Document Outline to the left of the canvas. (If you don't see the Document Outline, you can open it by clicking the item at Editor » Show Document Outline in the main menu).
Next, see if you have any constraints in place. If you do, remove them by selecting Editor » Resolve Auto Layout Issues » Clear Constraints under the menu item "section" that's titled All Views in ${YOUR_SCENE}.
Now, depending on what you're going for, there are different ways to go about setting up constraints, but here's what I would suggest. Assuming you want the street name to be centered vertically with the disclosure triangle, I would add a vertical constraint between the text field and its parent cell view like so:
With the text field selected in the Document Outline, click the Align icon in the lower right-hand corner of Interface Builder's main canvas area (see image).
In the popover that appears, check the checkbox next to Vertically in Container.
In the text field on the right side of the popover, enter a value of “0”.
Finally, click the “Add 1 Constraint” button.
You’ll probably see a red error (or yellow warning) sign show up, as the view has now opted into Auto Layout, but it only has a metric for its vertical position. So we now need to add some constraints to describe where the text field should be positioned on the x axis. Like before, we’ll define the constraints using the popover buttons on the lower right-hand side of the canvas:
Click the Add New Constraints button (the one to the right of the Align button).
On the diagram at the top of the popover, click the faint red lines on the left and right side of the white rectangle. This is telling Interface Builder we want to add leading and trailing constraints.
Now, enter the desired padding you want on each side of the text field. In the example image, I went with “4” points on both sides, but obviously, you can use whatever value(s) you think works best with your layout.
Finally, click the “Add 2 Constraints” button.
Any warning(s) that were present should now disappear, as we've added enough constraints to describe the position of the text field. In theory, you should now be able to build and run your project, and the text fields should be aligned with the disclosure triangles. With that said, there are plenty of other reasons a layout can get finicky, and considering usesAutomaticRowHeights is a new API in macOS High Sierra (and Steve Jobs is no longer there to beat it into Apple developers to make everything Just Work™), there could be issues that I'm unaware of.
Alternatively, you can set usesAutomaticRowHeights to false and have some object (e.g. a view controller, a NSObject subclass, etc.) conform to the NSOutlineViewDelegate protocol and implement the outlineView(_:heightOfRowByItem:) method to return any arbitrary height you want for different rows. The nice thing about sizing rows this way is that you can allow certain rows to be larger or smaller, depending on the role of the corresponding item. There are lots of tutorials on this, so I won't regurgitate a half-baked explanation here, but feel free to Google “Conforming to NSOutlineViewDelegate protocol” for more info.
Anyway, try the steps above, and see if they do anything for you, and if they don't, let me know. I can go as deep into the rabbit hole with you as you need, so just ask. Good luck!
For those like me who stumbled upon this issue many years later, here's the fix that worked for me, and requires a lot less work.
NSOutlineView has a function frameOfOutlineCell(atRow:) and the documentation states: You can override this method in a subclass to return a custom frame for the outline button cell
You can override the method in order to provide a frame that's actually in the vertical center of the row. And an important point that I learned from trial and error, is that you don't even need to provide that updated frame. Not sure if this is a bug or what, but for me, just calling super.frameOfOutlineCell(atRow: row) in the function override was enough to make the disclosure indicator appear in the correct location.
So my subclass of NSOutlineView is this:
class MyOutlineView: NSOutlineView {
override func frameOfOutlineCell(atRow row: Int) -> NSRect {
super.frameOfOutlineCell(atRow: row)
}
}
That's all. Hopefully that works for others as well!

XCode 4 Interface Builder: A better way to work with lots of overlapping views

In IB I have quite a few views that are shown. Many of them are hidden when the app loads, but are shown later when buttons are pressed. This is all fine, but when building this layout in IB it is extremely difficult to layout anything because there are so many overlapping views, some of which are partially transparent (ones that are set to hidden) and other are completely overlapping and covering others. This makes layout very hard.
What is the best method when laying out lots of views like this? Is there another way to break things up? Or better yet, can I hide a a view completely (like in photoshop) so that I can edit the ones underneath, then turn that layer back on?
Another option when trying to select a view that is obscured by another is the shortcut:
'ctrl' + 'shift' and click
It displays a list of all the views under the cursor.
I'm not aware of any way to hide objects in the canvas, but a useful trick for complex layouts is to double-click an item in the document tree to the left - this selects the item and puts focus on the canvas, you can the use the cursor keys to nudge it about.
This doesnt solve the problem of not being able to see things because there are, for example, five or six labels occupying the same space, but if that is the situation it may be a better idea to have a single label and change its contents in code.
I ran into this issue for an app I'm building that has an arial-view image of a park with clickable hotspots. When a hotspot is clicked a popup UIview is displayed with information about that spot in the park. I use the same VC/XIB for three parks. This makes the XIB really busy and hard to work with (i.e the same issue that you have) The detail UIViews make it hard to work with the views underneath. My workaround was to pick each detailed UIView that was hiding the part of the XIB I wanted to work on, and add 1000 to the UIView origin.x in the size inspector. This moved those UIViews enough out of the way for me to do what I needed to with the XIB. Then when I was done, I moved them back by x 1000. (I just needed to move them out horizontally to do what I needed to)
I know its clunky but given that XCode does not have a convenient way to hide portions of an XIB - it was the quickest approach I could think of!
One approach to handling overlapping items in IB is:
Ensure the groups of items that you want to hide are grouped into Views.
Give these Views names: e.g. ViewOptionA, ViewOptionB and ViewOptionC.
Can do this by clicking on name of view in the tree while it is selected and then typing new name.
When you want to hide one of those groups of items:
a) Select the View by either:
i) Clicking on it in the tree at the left or
ii) Ctrl-Shift Clicking in the layout editor and then select the view from the list.
b) In the Attributes Inspector set Alpha to 0.
When you want to unhide one of those groups of items:
As for 2) but set Alpha back to 1
[You do need to remember to unhide all views before you publish!
If you are forgetful like me then perhaps you could subclass UIView and set Alpha to 1. I haven't tried this subclassing idea yet.]

Smartgwt - create a panel with title and a border

This sounds like a pretty simple thing to do but I havent been able to find an easy way to do this. How do I create a panel with a title and a border which can contain my widgets? I have seen the SectionStack class which provides this. But I dont want to create a section stack.
Window can be added to a layout and drawn. But is it the only way or is there a container class that I am missing?
Also, how does one center things? Say a textfield and a button at the center of the page. How is this achieved?
If you are using a DynamicForm, you can give it a border and title with
form.setIsGroup(true);
form.setGroupTitle(title);
This actually works for Canvas, too (which is the superclass of most widgets and layouts in SmartGWT).
(I just had the same problem, and found this question, as well as the thread Is there a "titled Border" on the SmartGWT Forums, which gave this answer. I tried and it seems to work.)
To do form-related tasks, look into DynamicForm. To set the inputs in the form, you use setItems(Item...). A text field is a TextItem. You set it's title to control the label that SmartGWT will build. To get a title for the form, the best I've come up with is to use a container canvas that will contain both the title (probably a Label element) and the DynamicForm. To center the inputs, I believe you'd need to use setAlignment on the DynamicForm.
You could create an object that is actually a VLayout that contains a Label (the tile), has a border as you need and includes a Canvas (the generic stuff you want included).
In my experience, I noticed that very often I have a DynamicForm visible, so I just add a BlurbItem control to diplay the tile and a small explanation.