Exporting SQLite database into pdf with PDFJET

In this tutorial I will explain how to convert an SQLite database into pdf using a third party library, PDFJET. You can download the library, as well as the documentation, from this site. Make sure to download the open source library, which is free but relatively complete (there is also a more complete version, which you can use only for evaluation purposes, but you have to pay for it for developing your apps).

Why using PDFJET library

There are 3 main reasons for using PDFJET library in my opinion:

1. there is an open source version of the library (FREE);
2. it’s relatively complete (it has all the main features you need to create a pdf file);
3. it’s light (about 350 kb).

Of course if you need more advanced features you should better use the pay version of the library, or other librarries that you prefer.

Setting up your project (Eclipse) to use the library

To use PDFJET library in your project (Eclipse) follow these steps:

1. download the library from this page (open source version);
2. extract the files to a different folder;
3. in Eclipse create the package com.pdfjet in the src folder;
4. copy alla java files that you find in the folder open source\PDFjet-Open-Source\com\pdfjet in the package com.pdfjet that you have created;
5. import the package in your class with import com.pdfjet.

Now you can use the PDFJET library in your class.

Using the library

If you visit the PDFJET official site you’ll find dozens of examples about how to use the library and a complete documentation of all the classes available (the documentation can also be found in the library you download from the website: look at the folder open source\PDFjet-Open-Source\docs\java\com\pdfjet).

In this tutorial I will only give you a few examples of the instructions you can use to quickly convert an SQLite database into a pdf file.

Creating the pdf file

Let’s suppose we want to create a pdf file, Budget.pdf, in the external storage directory of our device. Here is the code:

String state = Environment.getExternalStorageState();

//check if the external directory is availabe for writing

if (!Environment.MEDIA_MOUNTED.equals(state)) {

return;

}

else {

File exportDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);

}

//if the external storage directory does not exists, we create it

if (!exportDir.exists()) {

exportDir.mkdirs();

}

File file;

file = new File(exportDir, "Budget.pdf");

//PDF is a class of the PDFJET library

PDF pdf = new PDF(new FileOutputStream(file));

//instructions to create the pdf file content

pdf.flush();

Title

Now suppose that we want to create a title and center it on the page (horizontally):

//first we create a page with portrait orientation

Page page = new Page(pdf, Letter.PORTRAIT);

//font of the title

Font f1 = new Font(pdf, CoreFont.HELVETICA_BOLD);

f1.setSize(7.0f);

//title: font f1 and color blue

TextLine title = new TextLine(f1, “TABLE’S TITLE”);

title.setFont(f1);

title.setColor(Color.blue);

//center the title horizontally on the page

title.setPosition(page.getWidth()/2 – title.getWidth()/2, 40f);

//draw the title on the page

title.drawOn(page);

Links

Here is the code to create a link to our website:

//font of the link

Font f2 = new Font(pdf, CoreFont.HELVETICA);

f2.setSize(7.0f);

//text of the link

TextLine website = new TextLine(f2, "Visit Website");

website.setColor(Color.blue);

website.setUnderline(true);

website.setURIAction("https://sites.google.com/site/flingsoftware/");

//position of the link

website.setPosition(40f, 40f);

//draw the link on the page

website.drawOn(page);

Creating a table

To convert an SQLite database into pdf we need of course a table. Here is the code to create it:

Table table = new Table();

List<List<Cell>> tableData = new ArrayList<List<Cell>>();

As you can see to create a table we use an ArrayList where each element is represented by another ArrayList containing Cell objects. Cell is a class of the PDFJET library used to create a single cell in the table.

Adding columns’ titles

List<Cell> columnTitles = new ArrayList<Cell>();

columnTitles.add(new Cell(f1, “COLUMN 1”);

columnTitles.add(new Cell(f1, “COLUMN 2”);

columnTitles.add(new Cell(f1, “COLUMN 3”);

columnTitles.add(new Cell(f1, “COLUMN 4”);

columnTitles.add(new Cell(f1, “COLUMN 5”);

columnTitles.add(new Cell(f1, “COLUMN 6”);

//light gray background and center alignment

for(int i=0; i<6; i++) {

   ((Cell) columnTitles.get(i)).setBgColor(Color.lightyellow);

   ((Cell) columnTitles.get(i)).setTextAlignment(Align.CENTER);

}

tableData.add(columnTitles);

In this example we created an ArrayList of Cells, each of which representing the title of a column, we set the color background and alignment of each Cell, and finally added the ArrayList to the “ArrayList of ArrayLists” tableData, our complete table.

Adding database records to the table

DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());

NumberFormat nf = NumberFormat.getCurrencyInstance(Locale.getDefault());

int i = 1;

while(myCursor.moveToNext()) {

   //retrieve data from cursor  

   Long date = myCursor.getLong(myCursor.getColumnIndex("date"));

   String item = myCursor.getString(myCursor.getColumnIndex("item"));

   Double amount = myCursor.getDouble(myCursor.getColumnIndex("amount"));

   String currency = myCursor.getString(myCursor.getColumnIndex("currency"));

   Double convAmount = myCursor.getDouble(myCursor.getColumnIndex("converted_amount"));

   String description = myCursor.getString(myCursor.getColumnIndex("description"));

   //next record in the table

   List<Cell> record = new ArrayList<Cell>();

   //create Cells and add them to the record

   Cell dateCell = new Cell(f2, df.format(new Date(date)));

   dateCell.setTextAlignment(Align.CENTER);

   record.add(dataCell);

   record.add(new Cell(f2, item));

   Cell amountCell = new Cell(f2, nf.format(amount));

   amountCell.setTextAlignment(Align.RIGHT);

   record.add(amountCell);

   Cell currencyCell = new Cell(f2, currency);

   currencyCell.setTextAlignment(Align.CENTER);

   record.add(currencyCell);

   Cell convAmountCell = new Cell(f2, nf.format(convAmount));

   convAmountCell.setTextAlignment(Align.RIGHT);

   record.add(convAmountCell);

   record.add(new Cell(f2, description));

   

   //add the record to the table

   tableData.add(record);

   //one line gray and one line white...

   if(i%2 == 0) {

dateCell.setBgColor(Color.lightgray);

amountCell.setBgColor(Color.lightgray);

        ...

   }

   i++;

}

In the previous example we iterate over the Cursor retrieved from the database and write each record in the table, field (each represented by a Cell object of the PDFJET library) after field.

Printing the table on the page

//populate the table with our tableData ArrayList

table.setData(tableData, Table.DATA_HAS_1_HEADER_ROWS);

//autoadjust column widths to fit the content

table.autoAdjustColumnWidths();

//let’s suppose we want to manually set the width of column 0

table.setColumnWidth(0, 40.0f);

//each cell can contain more rows

table.wrapAroundCellText();

table.setPosition(page.getWidth()/2 – table.getWidth()/2, 40f);

table.drawOn(page);

Printing the table on more than one page

If your table is particularly long and you need more than one page to print it, you can use the following loop:

int numOfPages = table.getNumberOfPages(page);

int currentPage = 0;

while (true) {

point = table.drawOn(page);

   //print page number

   TextLine numPag = new TextLine(f2, ++currentPage + “ of “ + numOfPages);

   numPag.setPosition(largPag - 30.0f - numPag.getWidth(), page.getHeight() - 20.0f);

   numPag.drawOn(page);

   //scrivo il nome tabella a fondo pagina

   TextLine tabella = new TextLine(f2,    mioContext.getString(R.string.menu_esporta_tabellaPdf_fondoPaginaSpese));

   tabella.setPosition(30.0f, page.getHeight() - 20.0f);

   tabella.drawOn(page);

   if (!table.hasMoreData()) {

      // Allow the table to be drawn again later:

      table.resetRenderedPagesCount();

      break;

   }

   page = new Page(pdf, Letter.PORTRAIT);

}

Exporting SQLite Database into .csv format

While developing my next app I came across an interesting problem: how do you export an SQLite database into .csv format? There are of course third party libraries that will do the job for you, but this is Android - The Technical Blog, so we want to understand "how stuff works" under the hood.

So let's start with Wikipedia...
According to Wikipedia csv stands for "comma separated values". CSV files are basically text files where values are separated by commas. There is not a formal standard defining .csv files, but the easiest way to convert an SQLite database into a .csv file is the following:

1. first you create a text file with the .csv extension. This way you can easily read the file with Excel or OpenOffice Calc, but you can also use .txt suffix for reading the file with Notepad;
2. you read the database one record after the other;
3. different records in the database are represented by different lines in the .csv file, while the fields of each record are separeted by commas.

In the following example we use the java.io.FileWriter class, because we want to create a text file writing one character at a time (2 bytes), and the java.io.PrintWriter class as a Decorator (remember the Decorator pattern in Java?), because we want to write one line at a time in the file.

Here you can download the code in a more readable format.

public boolean exportDatabase() {
DateFormat df = DateFormat.getDateInstance(DateFormat.SHORT, Locale.getDefault());

/**First of all we check if the external storage of the device is available for writing.
* Remember that the external storage is not necessarily the sd card. Very often it is
* the device storage.
*/
String state = Environment.getExternalStorageState();
if (!Environment.MEDIA_MOUNTED.equals(state)) { 
return false;
}
else {
//We use the Download directory for saving our .csv file.
   File exportDir = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS);      
   if (!exportDir.exists()) 
   {
       exportDir.mkdirs();
   }
   
   File file;
   PrintWriter printWriter = null;
   try 
   {
    file = new File(exportDir, "MyCSVFile.csv");
       file.createNewFile();                
       printWriter = new PrintWriter(new FileWriter(file));
                  
       /**This is our database connector class that reads the data from the database.
        * The code of this class is omitted for brevity.
        */
    DBCOurDatabaseConnector dbcOurDatabaseConnector = new DBCOurDatabaseConnector(myContext);
    dbcOurDatabaseConnector.openForReading(); //open the database for reading
   
    /**Let's read the first table of the database.
    * getFirstTable() is a method in our DBCOurDatabaseConnector class which retrieves a Cursor
    * containing all records of the table (all fields).
    * The code of this class is omitted for brevity.
    */
    Cursor curCSV = dbcOurDatabaseConnector.getFirstTable();
    //Write the name of the table and the name of the columns (comma separated values) in the .csv file.
    printWriter.println("FIRST TABLE OF THE DATABASE");
    printWriter.println("DATE,ITEM,AMOUNT,CURRENCY");
       while(curCSV.moveToNext())
       {
        Long date = curCSV.getLong(curCSV.getColumnIndex("date"));
        String item = curCSV.getString(curCSV.getColumnIndex("item"));
        Double amount = curCSV.getDouble(curCSV.getColumnIndex("amount"));
        String currency = curCSV.getString(curCSV.getColumnIndex("currency"));
       
        /**Create the line to write in the .csv file. 
        * We need a String where values are comma separated.
        * The field date (Long) is formatted in a readable text. The amount field
        * is converted into String.
        */
        String record = df.format(new Date(date)) + "," + item + "," + importo.toString() + "," + currency;
   printWriter.println(record); //write the record in the .csv file
}
 
curCSV.close();
dbcOurDatabaseConnector.close();
   }
  
  catch(Exception exc) {
  //if there are any exceptions, return false
  return false;
  }
  finally {
  if(printWriter != null) printWriter.close();
  }
  
  //If there are no errors, return true.
  return true;
}
}