io.github.palexdev.virtualizedfx.cells.VFXLabeledCellSkin Maven / Gradle / Ivy

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/*
 * Copyright (C) 2024 Parisi Alessandro - [email protected]
 * This file is part of VirtualizedFX (https://github.com/palexdev/VirtualizedFX)
 *
 * VirtualizedFX is free software: you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public License
 * as published by the Free Software Foundation; either version 3 of the License,
 * or (at your option) any later version.
 *
 * VirtualizedFX is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
 * See the GNU Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with VirtualizedFX. If not, see .
 */

package io.github.palexdev.virtualizedfx.cells;

import io.github.palexdev.mfxcore.controls.Label;
import io.github.palexdev.mfxcore.controls.SkinBase;
import io.github.palexdev.mfxcore.events.WhenEvent;
import io.github.palexdev.mfxcore.observables.When;
import io.github.palexdev.virtualizedfx.events.VFXContainerEvent;
import javafx.beans.InvalidationListener;
import javafx.beans.value.ChangeListener;
import javafx.geometry.HPos;
import javafx.geometry.VPos;

import java.beans.EventHandler;

import static io.github.palexdev.mfxcore.events.WhenEvent.intercept;
import static io.github.palexdev.mfxcore.observables.When.onInvalidated;

/**
 * Simple skin implementation to be used with any descendant of {@link VFXCellBase}.
 * 
 * This will display the data specified by the {@link VFXCellBase#itemProperty()} as a {@code String} in a {@link Label}.
 * It's the only children of this skin, takes all the available space and has the following properties bound to the cell:
 * 
 - the alignment property bound to {@link VFXCellBase#alignmentProperty()}
 * 
 - the graphic property bound to {@link VFXCellBase#graphicProperty()}.
 * 

 * The label's text will be updated on two occasions:
 * 
 1) when the {@link VFXCellBase#itemProperty()} is invalidated
 * 
 2) when an event of type {@link VFXContainerEvent#UPDATE} reaches the cell
 * 

 * You can modify {@link #addListeners()} to change such behavior. For example, rather than using an {@link InvalidationListener}
 * you could use a {@link ChangeListener} instead, add your own logic, etc. (useful when you want to optimize update performance).
 * 

 * (It's recommended to use {@link #listeners(When[])}, {@link #events(WhenEvent[])} and in general {@link When} constructs.
 * Simply because they make your life easier, also disposal would be automatic this way).
 * 

 * Last but not least, the label's text is updated by the {@link #update()} method.
 */
public class VFXLabeledCellSkin extends SkinBase, CellBaseBehavior> {
	//================================================================================
	// Properties
	//================================================================================
	protected final Label label;

	//================================================================================
	// Constructors
	//================================================================================
	public VFXLabeledCellSkin(VFXCellBase cell) {
		super(cell);

		// Init label
		label = new Label();
		label.alignmentProperty().bind(cell.alignmentProperty());
		label.graphicProperty().bind(cell.graphicProperty());

		// Finalize init
		addListeners();
		getChildren().add(label);
	}

	//================================================================================
	// Methods
	//================================================================================

	/**
	 * Adds an {@link InvalidationListener} on the {@link VFXCellBase#itemProperty()} to call {@link #update()} when it changes,
	 * and an {@link EventHandler} to support "manual" updates through events of type {@link VFXContainerEvent#UPDATE}.
	 * 

	 * (Uses {@link When} and {@link WhenEvent} constructs).
	 *
	 * @see #listeners(When[])
	 * @see #events(WhenEvent[])
	 */
	protected void addListeners() {
		VFXCellBase cell = getSkinnable();
		listeners(
			onInvalidated(cell.itemProperty())
				.then(t -> update())
				.executeNow()
		);
	}

	/**
	 * This is responsible for updating the label's text using the value specified by the {@link VFXCellBase#itemProperty()}.
	 * 
	 * If the item is {@code null} sets the text to an empty string, otherwise calls {@code toString()} on it.
	 */
	protected void update() {
		VFXCellBase cell = getSkinnable();
		T item = cell.getItem();
		if (item == null) {
			label.setText("");
			return;
		}
		label.setText(item.toString());
	}

	//================================================================================
	// Overridden Methods
	//================================================================================
	@Override
	protected void initBehavior(CellBaseBehavior behavior) {
		VFXCellBase cell = getSkinnable();
		behavior.init();
		events(
			intercept(cell, VFXContainerEvent.UPDATE)
				.process(e -> {
					update();
					e.consume();
				})
		);
	}

	@Override
	protected double computePrefWidth(double height, double topInset, double rightInset, double bottomInset, double leftInset) {
		return leftInset + label.prefWidth(-1) + rightInset;
	}

	@Override
	protected void layoutChildren(double x, double y, double w, double h) {
		label.resize(w, h);
		positionInArea(label, x, y, w, h, 0, HPos.LEFT, VPos.CENTER);
	}
}