Menampilkan Alert pada Layar Mobile

Agar kita bisa membuat midlet, kita harus membuat subclass dari midlet.
Pada saat meng-extends canvas pasti ada perintah untuk memanggil abstrak method yaitu " protected void paint(Graphics g)"

Inilah script class midletnya :



import javax.microedition.lcdui.*;

class HelloCanvas extends Canvas implements CommandListener {

    private Command exitCommand = new Command("Exit",Command.EXIT,0);
    private percobaan5 midlet;
    private String text;

   public HelloCanvas(percobaan5 midlet,String text){
       this.midlet = midlet;
       this.text = text;
       addCommand(exitCommand);
       setCommandListener(this);

   }
   protected void paint(Graphics g) {
       g.setColor(255,255,255);
       g.fillRect(0,0,getWidth(),getHeight());
       g.setColor(0,0,0);
       g.drawString(text,getWidth()/2,getHeight()/2,Graphics.TOP |
Graphics.HCENTER);
   }
   public void commandAction(Command c,Displayable d){
       if(c == exitCommand){
           midlet.Quit();
       }
   }
}

Untuk menggambar warna , string , dan garis ,ini script subclassnya :

import javax.microedition.lcdui.*;

class HelloCanvas extends Canvas implements CommandListener {

    private Command exitCommand = new Command("Exit",Command.EXIT,0);
    private percobaan5 midlet;
    private String text;

   public HelloCanvas(percobaan5 midlet,String text){
       this.midlet = midlet;
       this.text = text;
       addCommand(exitCommand);
       setCommandListener(this);

   }
   protected void paint(Graphics g) {
       g.setColor(255,255,255);
       g.fillRect(0,0,getWidth(),getHeight());
       g.setColor(0,0,0);
       g.drawString(text,getWidth()/2,getHeight()/2,Graphics.TOP |
Graphics.HCENTER);
   }
   public void commandAction(Command c,Displayable d){
       if(c == exitCommand){
           midlet.Quit();
       }
   }
}

Maka tampilannya aka seperti ini :