import java.awt.*; import java.awt.event.*; import java.applet.*; public class AMMTM extends Applet implements ActionListener { private TextField txt1, txt2, txt3, txt4; private Label lOut; private Button bMIN, bMAX, bTOT, bMED; public void init() { this.setLayout(new BorderLayout()); Panel pNORTH=new Panel(); txt1=new TextField("-20", 10); pNORTH.add(txt1); txt2=new TextField("-1" , 10); pNORTH.add(txt2); txt3=new TextField("+1" , 10); pNORTH.add(txt3); txt4=new TextField("+20", 10); pNORTH.add(txt4); this.add(pNORTH, BorderLayout.NORTH); lOut =new Label("???", Label.CENTER); this.add(lOut, BorderLayout.CENTER); Panel pSOUTH=new Panel(); bMIN=new Button("Minimo"); bMIN.addActionListener(this); pSOUTH.add(bMIN); bMAX=new Button("Massimo"); bMAX.addActionListener(this); pSOUTH.add(bMAX); bTOT=new Button("Totale"); bTOT.addActionListener(this); pSOUTH.add(bTOT); bMED=new Button("Media"); bMED.addActionListener(this); pSOUTH.add(bMED); this.add(pSOUTH, BorderLayout.SOUTH); } public void actionPerformed(ActionEvent evento) { Button comando=(Button)evento.getSource(); String msg =new String(); try { double in1=Double.parseDouble(txt1.getText()); double in2=Double.parseDouble(txt2.getText()); double in3=Double.parseDouble(txt3.getText()); double in4=Double.parseDouble(txt4.getText()); double risultato=0; if(comando==bMIN) { risultato=Math.min(Math.min(in1, in2), Math.min(in3, in4)); msg="Minimo = " + risultato; } else if(comando==bMAX) { risultato=Math.max(Math.max(in1, in2), Math.max(in3, in4)); msg="Massimo = " + risultato; } else if(comando==bTOT) { risultato=in1+in2+in3+in4; msg="Totale = " + risultato; } else if(comando==bMED) { risultato=(in1+in2+in3+in4)/4.0; msg="Media = " + risultato; } } catch(Exception eccezione) { msg="??? Input errato ???"; } lOut.setText(msg); } public static void main(String[] args) { AMMTM aMMTM = new AMMTM(); } }
Osserva
this.setLayout(new BorderLayout());