Sample Mobile Device Application to Generate and Display Barcode Image

In this section, we will create a sample mobile application in Netbeans IDE to generate a barcode image. We will provide a textbox for getting the codetext value, generate a Pdf417 2D barcode image and display it on the mobile screen. Open Netbeans IDE and create a new mobile device application. Please refer to Setting the Environment for preparing the development environment and adding reference to Aspose.BarCode.J2ME.jar package. As mentioned in Setting the Environment, after creating a new project, you will see HelloMIDlet.java file that is created by the project wizard. We will make some modifications in this file to generate the barcode image.

Working

The screen contains a default “screen item” with hello world text. Delete it, by right clicking on it and choosing “Delete” from the context menu.

The screen will now be empty, without any control. Right click on the screen; choose “New/Add” -> “Text Field” from the context menu. A text field control will be added. Set the label to “Codetext:” and text to “test-123”. The screen would look like the below one after doing these modifications.


We will use this textbox to get the codetext from screen for generating the barcode.

For rendering the barcode image on screen, we will use a custom item. For this purpose, we will create a new class which will extend from “CustomItem” class. This class will add an image on the screen area and render the barcode image to the display. Public methods will be added in this class to generate and render the barcode image from the application. Below is the complete code for this class. Add this class to your sample project, by copying the code.

[Java]

package hello;
import com.aspose.j2me.barcode.generation.BarCodeBuilder;
import com.aspose.j2me.barcode.generation.Symbology;
import com.aspose.j2me.barcode.generation.GraphicsUnit;
import javax.microedition.lcdui.CustomItem;
import javax.microedition.lcdui.Graphics;
import javax.microedition.lcdui.Image;
/**
 * Sample class for using Aspose.BarCode for J2ME
 * Shows how to create a CustomItem to paint barcodes.
 */
public class SampleBarCodeItem extends CustomItem {
    protected SampleBarCodeItem(String s) {
        super(s);
    }

    protected int getMinContentWidth() {
        return 200;
    }

    protected int getMinContentHeight() {
        return 200;
    }

    protected int getPrefContentWidth(int i) {
        return i;
    }

    protected int getPrefContentHeight(int i) {
        return i;
    }

    // default codetext
    private String _codeText = "12345";
    // symbology
    private long _symbology = Symbology.Code128;
    private Image _img = null;

    // set codetext
    public void setCodeText(String code)
    {
        this._codeText = code;
    }

    // set symbology
    public void setSymbologyType(long sym)
    {
        this._symbology = sym;
    }

    // instance of BarCodeBuilder class
    private BarCodeBuilder barcodeBuilder;

    // paint method for displaying the barcode image
    protected void paint(Graphics g, int w, int h) {

        // initialize with default values, if null
        if(barcodeBuilder == null)
        {
            barcodeBuilder =  new BarCodeBuilder(_symbology,_codeText);
        }
        else
        {
            barcodeBuilder.setSymbologyType(_symbology);
            barcodeBuilder.setCodeText(_codeText);
        }

        // set properties
        barcodeBuilder.setGraphicsUnit(GraphicsUnit.PIXEL);
        barcodeBuilder.setxDimension(2);
        barcodeBuilder.setBarHeight(50);
        barcodeBuilder.setWideNarrowRatio(2);
        barcodeBuilder.setBorderVisible(false);
        barcodeBuilder.setCodeTextVisible(true);

        // create an image
        if(_img == null)
        {
            _img = Image.createImage(w,h);
        }

        // get Graphics
        Graphics g1 = _img.getGraphics();

        g1.setForeColor(0xFFFFFFFF);
        g1.fillRect(0,0,w,h);

        // render the barcode image on the display area
        barcodeBuilder.render(g1);
        g.drawImage(_img,0,0,Graphics.TOP | Graphics.LEFT);
    }

    // call this method to draw barcode image
    public void repaintBarCode() {
        this.repaint();
    }

    // get barcode image
    public Image getImage() {
        return this._img;
    }
}
 

private SampleBarCodeItem bc;
public void startApp()
{
    if (midletPaused)
    {
        resumeMIDlet();
    }
    else
    {
        initialize();
        startMIDlet();

        // initialize the custom item
        bc = new SampleBarCodeItem("Aspose-BarCode Generation ");
        this.form.append(bc);
        bc.setPreferredSize(300, 200);
    }
    midletPaused = false;
}
 

// method to generate the barcode and render on device screen
public void generateBarcode()
{
    bc.setCodeText(txtCodetext.getString());
    bc.setSymbologyType(Symbology.Pdf417);
    bc.repaintBarCode();

}
 

A similar example with all source code is also provided with the Aspose.BarCode for Java zip package.