GridLayout

Arranges children in a grid: each row has its own split of columns by fraction, and the row height comes from the tallest component. Great for “label : field” forms.

🟡 · Package: dev.crossfly.ui.layout · Extends: Layout

When to use

Aligned forms (label | field) with a stable ratio.
Simple tables of cells.

When NOT to use

A single column → VerticalLayout.
Anchoring one component to another → RelativeLayout.

`add(...)` — signature and semantics (mind the order!)

public GridLayout add(Object... v)   // ALL the widths, then ALL the components

Pass all widths first, then all components (same count):

Width	Meaning
`> 0` (ex. `0.35f`)	fraction of the grid width (35%)
`LAY_AUTO` (`0f`)	automatic width (the cell uses the content’s size)

Constructors

Constructor	Description
`new GridLayout()`	`START`/`START` alignment
`new GridLayout(Position h, Position v)`	horizontal/vertical alignment of the rows

Full example (copy, paste and run)

package com.exemplo;

import dev.crossfly.ui.*;
import dev.crossfly.ui.layout.*;

/** Runnable main screen. Point the launcher (classname) and run: gradlew :lwjgl3:run */
public class MainWindow extends Window
{
   @Override
   public void onShow() throws Exception
   {
      super.onShow();

      GridLayout form = new GridLayout(Position.START, Position.START);
      // label (35%) | field (65%) — widths first, components after:
      form.add(0.35f, 0.65f, new Label("Nome"),     new TextField(""));
      form.add(0.35f, 0.65f, new Label("E-mail"),   new TextField(""));
      form.add(0.35f, 0.65f, new Label("Telefone"), new TextField(""));

      Component painel = new Component();
      painel.setLayout(form);

      setLayout(new VerticalLayout(Position.START, Position.START));
      add(LAY_AUTO, new Label("Cadastro"));
      add(LAY_FILL, painel);
   }
}

The snippets below show only the core (what goes inside onShow()). To run them, place them in the MainWindow skeleton above.

Basic usage

GridLayout form = new GridLayout(Position.START, Position.START);
// label (35%) | field (65%) — widths first, components after:
form.add(0.35f, 0.65f, new Label("Nome"),     new TextField(""));
form.add(0.35f, 0.65f, new Label("E-mail"),   new TextField(""));
form.add(0.35f, 0.65f, new Label("Telefone"), new TextField(""));

Component painel = new Component();
painel.setLayout(form);

How it arranges

┌───────────┬──────────────────────┐
│ Nome (35%)│ [campo]        (65%)  │  ← linha 1
├───────────┼──────────────────────┤
│ E-mail    │ [campo]              │  ← linha 2
└───────────┴──────────────────────┘

Best practices

A row’s fractions add up to ~1.0 to cover the width.
Rows may have different column counts (each add defines a row).

Common mistakes

Interleaving width and component: add(0.35f, label, 0.65f, field) → throws UIException. The correct form is add(0.35f, 0.65f, label, field) (widths together, then components).
Number of widths ≠ number of components → UIException (cols*2 == args).