How to get a Grid component to auto-adjust its width?

Hello fellow Vaadin users.
I am currently teaching myself Vaadin 14 by tinkering a bit with a Rasperry PI.
The project uses a small sensor for motion detection.
To control the whole thing, i created a Vaadin Flow GUI (it is still in a very early testing stage without actual hardware interaction).
For the settings page i wanted to make some kind of table-like structure in which every row shows a certain option, a current state and a button or other component to manipulate it. My problem is, that i can’t get the grid element to expand its size to show all colums of the grid at once without a scrollbar.

To be a bit more specific, here are some details about the setup:

The main view element hosts a tab element which enables/sets the visibility of some div elements. One of those div elements is the settings element which has a vertical layout and holds the grid itself.

The structure looks like this:

Mainview
	VerticalLayout
		Tabs
		StatusDiv
			VerticalLayout
				Grid
		SettingsDiv
		InfoDiv
		LoginDiv

The settings div has the following view setup code:

VerticalLayout layout = new VerticalLayout();
layout.setAlignItems(Alignment.CENTER);
add(layout);

H2 heading = new H2("Einstellungen");
layout.add(heading);

Label infoLabel = new Label("Hier ist die Einstellungen Seite.");
layout.add(infoLabel);	
layout.setWidthFull();

List<SimpleGridComponentTriple> gridItems = new ArrayList<SimpleGridComponentTriple>();
gridItems.add(new SimpleGridComponentTriple(new Label("Test1"), new Label("Test1"), new Label("Test1")));
gridItems.add(new SimpleGridComponentTriple(new Label("Test2"), new Label("Test2"), new Label("Test2")));
gridItems.add(new SimpleGridComponentTriple(new Label("Test3"), new Label("Test3"), new Button("Test3")));
Grid<SimpleGridComponentTriple> grid = new Grid<>();
grid.setItems(gridItems);
grid.addComponentColumn(SimpleGridComponentTriple::getFirst).setHeader("Option").setFlexGrow(0);
grid.addComponentColumn(SimpleGridComponentTriple::getSecond).setHeader("Status").setFlexGrow(0);
grid.addComponentColumn(SimpleGridComponentTriple::getThird).setHeader("Aktion").setFlexGrow(0);
grid.setSelectionMode(SelectionMode.NONE);
layout.add(grid);
grid.setWidth("100%");
grid.setWidthFull();
grid.setHeightByRows(true);

For testing the row entries, i created a SimpleGridComponentTriple class which lets my put differnt kinds of components in each field of the grids row.

public class SimpleGridComponentTriple {

	private Component first;
	private Component second;
	private Component third;
	
	public SimpleGridComponentTriple(Component first, Component second, Component third) {
		
		if (first == null) {
			first = new Label(" ");
		}
		this.first = first;
		
		if (second == null) {
			second = new Label();
			second.setVisible(false);
		}
		this.second = second;
		
		if (third == null) {
			third = new Label();
			third.setVisible(false);
		}
		this.third = third;
	}
	
	public Component getFirst() {
		return first;
	}
	public Component getSecond() {
		return second;
	}
	public Component getThird() {
		return third;
	}
}

I hope this all helps to understand the setup.
Does someone have a hint on how to get the grid to auto-adjust the width to the needed space to show all of its elements?
Currently it only shows a grid as wide as the label above it.

Any help would be very much appreciated.
Greetings to all of you
Alexander

Dear fellow Vaadin users.
Today i was able to get a step closer to a possible solution but i am not there yet.
I was able to adjust the size of the grid element to show all elements by setting the div element it is nested in to full size.

Mainview
	VerticalLayout
		Tabs
		StatusDiv <-.setSizeFull()
			VerticalLayout
				Grid
		SettingsDiv
		InfoDiv
		LoginDiv

This results in a change to this:

As you can see, the grid now stretches over the full screen. It does no longer matter whether the grid is set to full width or not (grid.setWidthFull()).
Is there a option for the grid like the one for the height (grid.setHeightByRows(true)) to get it to adjust the width to the needed column space? Or does someone have a idea on how to calculate the needed width to set it manually?

There is no way to let the grid “shrink” down to only its necessary width. Instead, you should decide how wide the grid should be (usually full width), and then give any excess space to some columns. You can define which columns get how much excess space using column::setFlexGrow.

So here is what I would do in your shoes:

  1. Use the space that you have. There is no point in minimizing the Grid to its smallest possible size, if you don’t use the space that is thereby created. This means leaving the status-div at fullwidth, and also setting the grid to full width. On a sidenote, I would also set the Tabs to full width, it just looks better IMO.

  2. set the width on each column. Here you can define the minimal needed width of each column. Let’s just assume 100px for each of your columns.

grid.addComponentColumn(item -> item.getFirst())
	.setHeader("Option")
	.setWidth("100px");
  1. After implementing the last step, we are now still at a similar point as your last screenshot. Now we get to add flexGrow information on all columns:
grid.addComponentColumn(item -> item.getFirst())
	.setHeader("Option")
	.setWidth("100px")
	.setFlexGrow(1);

Setting flexGrow to 1 on each column will make each column expand the same percentile. If you have one column with flexGrow 0, one column with flexGrow 1, and one with flexGrow 2: then the first will always stay at 100px, and the last column is always allocated double the excess space than the middle column.
In your case, setting all columns to flexGrow 1 should be fine.

@Kaspar Scherrer
Thank you for your answer.
I did try the changes you suggested.
They brought me a step closer to where i want to go.

At the moment i got my GUI to look like this:

I did so by using the settings you suggested and giving the grid itself a fixed size, calculated by the column widths sum plus a little safety margin (the initial value of 20). Sadly this only works when i set a actual value to each column with the setWidth() method. This fact makes the calculation pointless.

List<SimpleGridComponentTriple> gridItems = new ArrayList<SimpleGridComponentTriple>();
gridItems.add(new SimpleGridComponentTriple(new Label("Test1"), new Label("Test1"), new Label("Test1")));
gridItems.add(new SimpleGridComponentTriple(new Label("Test2"), new Label("Test2"), new Label("Test2")));
gridItems.add(new SimpleGridComponentTriple(new Label("Test3"), new Label("Test3"), new Button("Test3")));
Grid<SimpleGridComponentTriple> grid = new Grid<>();
grid.setItems(gridItems);
grid.addComponentColumn(SimpleGridComponentTriple::getFirst).setHeader("Option").setWidth("120px").setFlexGrow(1);
grid.addComponentColumn(SimpleGridComponentTriple::getSecond).setHeader("Status").setWidth("120px").setFlexGrow(1);
grid.addComponentColumn(SimpleGridComponentTriple::getThird).setHeader("Aktion").setWidth("120px").setFlexGrow(1);
grid.setSelectionMode(SelectionMode.NONE);
layout.add(grid);
grid.setHeightByRows(true);

int width = 20; //initial value, works with width >=2 but i used 20 just to be sure
for (Grid.Column<SimpleGridComponentTriple> column : grid.getColumns())
	width += Integer.parseInt(column.getWidth().replaceAll("\\D+",""), 10);
grid.setWidth("" + width + "px");

If i could get the actual size of a Component, i could calculate the needed width without setting one for each column. As far as i understand there is no option to get a components actual size as they are changing depending on the individual browser settings. So calculating the width like i did is pointless as i could simply give it a fixed size from the start.

It would be so great if there was a Grid method setWidthByColums(true) just like the existing setHeightByRows(true).

Big upvote for setWidthByColums(true) !!!

Have you had any progress?