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Home » Eclipse Projects » JFace » [SOLVED] [Databinding] - Bind a Text widget and a ListViewer for modification
[SOLVED] [Databinding] - Bind a Text widget and a ListViewer for modification [message #1783789] Sat, 17 March 2018 11:22 Go to next message
Goran M. is currently offline Goran M.Friend
Messages: 12
Registered: April 2012
Junior Member
Hi,

I got a ListViewer showing a bunch of objects. Below the ListViewer there are several text widgets bind to corresponding valuef of the object.

When I select one element of the list, the corresponding value is shown in the text widget.

Now here comes the strange part: When I modify the value in the text widget, the element disapears in the list.

If I use a ComboViewer instead of a ListViewer, the selected element is also changed simultaneously.

Here is my test code:

package de.test;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeSupport;
import java.util.ArrayList;

import org.eclipse.core.databinding.DataBindingContext;
import org.eclipse.core.databinding.beans.BeanProperties;
import org.eclipse.core.databinding.observable.Realm;
import org.eclipse.core.databinding.observable.list.WritableList;
import org.eclipse.jface.databinding.swt.DisplayRealm;
import org.eclipse.jface.databinding.swt.WidgetProperties;
import org.eclipse.jface.databinding.viewers.ViewerProperties;
import org.eclipse.jface.databinding.viewers.ViewerSupport;
import org.eclipse.jface.viewers.ListViewer;
import org.eclipse.swt.SWT;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Label;
import org.eclipse.swt.widgets.List;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

public class ListBindingTest {

	protected Shell shell;
	private Text txtName;
	private java.util.List<Sandwich> sandwichs;
	private ListViewer listViewer;

	/**
	 * Launch the application.
	 * 
	 * @param args
	 */
	public static void main(String[] args) {
		Realm.runWithDefault(DisplayRealm.getRealm(Display.getDefault()), new Runnable() {
			public void run() {
				try {
					ListBindingTest window = new ListBindingTest();
					window.open();
				} catch (Exception e) {
					e.printStackTrace();
				}
			}
		});

	}

	/**
	 * Open the window.
	 */
	public void open() {
		Display display = Display.getDefault();
		createContents();
		shell.open();
		shell.layout();
		while (!shell.isDisposed()) {
			if (!display.readAndDispatch()) {
				display.sleep();
			}
		}
	}

	/**
	 * Create contents of the window.
	 */
	protected void createContents() {
		shell = new Shell();
		shell.setSize(450, 300);
		shell.setText("SWT Application");
		shell.setLayout(new GridLayout(2, false));

		Label lblNewLabel = new Label(shell, SWT.NONE);
		lblNewLabel.setLayoutData(new GridData(SWT.LEFT, SWT.TOP, false, false, 1, 1));
		lblNewLabel.setText("New Label");

		listViewer = new ListViewer(shell, SWT.BORDER | SWT.V_SCROLL);
		List list = listViewer.getList();
		list.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 1, 1));
		new Label(shell, SWT.NONE);
		new Label(shell, SWT.NONE);

		sandwichs = new ArrayList<>();
		sandwichs.add(new Sandwich("Bacon sandwich"));
		sandwichs.add(new Sandwich("Bacon, egg and cheese"));
		sandwichs.add(new Sandwich("Bagel toast"));
		sandwichs.add(new Sandwich("Baked bean"));
		sandwichs.add(new Sandwich("Bánh mì"));
		sandwichs.add(new Sandwich("Barbecue"));
		sandwichs.add(new Sandwich("Barros Jarpa"));
		sandwichs.add(new Sandwich("Barros Luco"));

		Label lblNewLabel_1 = new Label(shell, SWT.NONE);
		lblNewLabel_1.setLayoutData(new GridData(SWT.RIGHT, SWT.CENTER, false, false, 1, 1));
		lblNewLabel_1.setText("New Label");

		txtName = new Text(shell, SWT.BORDER);
		txtName.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 1, 1));

		initDatabinding();

	}

	@SuppressWarnings({ "rawtypes", "unchecked" })
	private DataBindingContext initDatabinding() {
		DataBindingContext bindingContext = new DataBindingContext();

		WritableList input = new WritableList(sandwichs, String.class);
		ViewerSupport.bind(listViewer, input, BeanProperties.value(Sandwich.class, "name"));

		bindingContext.bindValue(WidgetProperties.text(SWT.Modify).observe(txtName), BeanProperties
				.value(Sandwich.class, "name").observeDetail(ViewerProperties.singleSelection().observe(listViewer)));

		listViewer.setInput(input);

		return bindingContext;

	}

	class Sandwich {
		private String name;
		private PropertyChangeSupport propertyChangeSupport = new PropertyChangeSupport(this);

		public Sandwich() {
		}

		public Sandwich(String name) {
			setName(name);
		}

		public String getName() {
			return name;
		}

		public void setName(String name) {
			propertyChangeSupport.firePropertyChange("name", this.name, this.name = name);
		}

		public void addPropertyChangeListener(PropertyChangeListener l) {
			propertyChangeSupport.addPropertyChangeListener(l);
		}

		public void removePropertyChangeListener(PropertyChangeListener l) {
			propertyChangeSupport.removePropertyChangeListener(l);
		}

		@Override
		public String toString() {
			return "Sandwich [name=" + name + "]";
		}

		@Override
		public int hashCode() {
			final int prime = 31;
			int result = 1;
			result = prime * result + getOuterType().hashCode();
			result = prime * result + ((name == null) ? 0 : name.hashCode());
			return result;
		}

		@Override
		public boolean equals(Object obj) {
			if (this == obj)
				return true;
			if (obj == null)
				return false;
			if (getClass() != obj.getClass())
				return false;
			Sandwich other = (Sandwich) obj;
			if (!getOuterType().equals(other.getOuterType()))
				return false;
			if (name == null) {
				if (other.name != null)
					return false;
			} else if (!name.equals(other.name))
				return false;
			return true;
		}

		private ListBindingTest getOuterType() {
			return ListBindingTest.this;
		}

	}

}



Does anybody have an idea how to get the same behaviour like when using a ComboViewer? I would like to see the modification simultaneously in the text widget and in the ListViewer.

Best regards
Goran

[Updated on: Sat, 17 March 2018 11:46]

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Re: [SOLVED] [Databinding] - Bind a Text widget and a ListViewer for modification [message #1783790 is a reply to message #1783789] Sat, 17 March 2018 11:46 Go to previous message
Goran M. is currently offline Goran M.Friend
Messages: 12
Registered: April 2012
Junior Member
I found the "solution".

The "problem" are the hashCode() and equals() methods. If I remove them, the change is done simultaneously.

Not sure if this the best solution or not.
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