Tutorial: SQLite and Processing, Part II

--D. Thiebaut 17:01, 30 June 2011 (EDT)
Updated --D. Thiebaut (talk) 17:03, 31 July 2013 (EDT)

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This is the second part of a quick tutorial to accessing an SQLite database from Processing. Check out Part 1 for how to run the example in Processing's IDE. This tutorial uses Processing 2.

Setup

• First follow the steps of this great tutorial for creating Processing applications with Eclipse. Remember the steps for adding the core.jar library to your Eclipse project. You will need to repeat them for every new Processing project you want to create. The other option you'll have is to copy paste the skeleton project into another new project, in which case the core library should follow automatically into your new project.
• Note: sometimes it is hard to get the Build Path option for the core.jar file. If this option does not appear, a work-around is to right click on the project, and pick Properties, Java Build Path, then click on the Libraries tab, then Add Jar, pick the core.jar file, and then click Ok.

Download SQLite Library

• We download the SQLite library recommended on the Procssing/libraries Website: the Bezier SQLib library.
• We need 3 files from the library, which is setup to use inside a sketch, but with Eclipse we need to reorganize them slightly.
• In a Terminal window (we are working on a Mac, the procedure is similar under Windows):

  cd ~/Downloads
  ls
  BezierSQLib-0.2.0.zip             (the file we just downloaded from http://processing.org/reference/libraries/)

  mkdir Bezier
  mv BezierSQLib-0.2.0.zip  Bezier
  cd Bezier
  unzip BezierSQLib-0.2.0.zip 
  ls 

  BezierSQLib-0.2.0.zip	examples/		library.properties
  documentation/		library/		source/

  cp library/sqlite-jdbc-3.7.2.jar ..         (copy the sqlite jdbc file in ~/Download folder)
  cp source/de/bezier/data/sql/SQL*.java ..   (copy SQL.java and SQLite.java to ~/Download folder)
  cp source/de/bezier/data/sql/mapper/NameMapper.java ..
  cp source/de/bezier/data/sql/mapper/UnderScoreToCamelCaseMapper.java ..

The Download folder should now contain six files

  ls -1 ~/Downloads
  Bezier/
  NameMapper.java
  SQLite.java
  SQL.java
  sqlite-jdbc-3.7.2.jar
  UnderScoreToCamelCaseMapper
 

• Edit the java files and modifiy their headers as shown below (the added text is in red):
  • SQL.java

// package de.bezier.data.sql;                                                                                   
import processing.core.*;
// import de.bezier.data.sql.mapper.*;                                                                           
import mapper.*
import java.io.*;
import java.sql.*;
. . .
(remaining of the file unchanged)
 

• • SQLite.java

//package de.bezier.data.sql;                                                                                

import processing.core.*;
import java.util.ArrayList;

/**                                                                                                          
 *              SQLite wrapper for SQL library for Processing 2+                                             
 */

//public class SQLite extends de.bezier.data.sql.SQL                                                         
public class SQLite extends SQL {

Main Project Class

• Open Eclipse and create a new Java Project
• Create a new class in your package, and call it Main.java.
• In the Edit Window, enter the following code:

package tutorial1;

import processing.core.*;

public class Main extends PApplet {

	public void setup() {
		// define the window size, make graphics softer, and make
		// the background white
		size(600, 600);
		smooth();
		background(255);
	}

	public void draw() {
                // erase screen
		background(255);

                // change color of circle paint depending on mouse button
		if (mousePressed) 
			fill(0);
		else 
			fill(255);
		
                // draw a circle where the mouse is located
		ellipse(mouseX, mouseY, 80, 80);
	}
}

• Click on the white triangle in a green circle under the top menu, and run the Applet. Notice that a circle should appear and follow the mouse. Notice also that it should change color as you click the mouse button.