Dasturlash tili
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Java haqida boshlangich darslik by Ali Artukov (z-lib.org)
Tugmalar va yozuvlar
Tugma bu biron bir amalni bajarish uchun foydalanuvchi ruxsatini olish uchun ishlatiladigan element xisoblanadi. Java dasturlash tilida tugmalarni JButton
klassi andozasi yordamida yaratib olish mumkin. Masalan: JButton button = new JButton(); Dastur kodi yangi tugma yaratib uni button o’zgaruvchisiga biriktirib beradi. Yuqoridagi dastur kodi xech qanday yozuvga ega bo’lmagan tugmani yaratib beradi. Ammo, foydalanishni osonlashtirish maqsadida xar bir tugma bajaradigan amaliga asosan nomga ega bo’lishi kerak. Nomga ega tugmani yaratib olish uchun quyidagi dastur kodidan foydalanish mumkin: JButton button = new JButton("OK"); Ushbu dastur kodi quyidagi tugmani yaratib beradi
JButton klassi tugmalarga matndan tashqari rasm joylashtirish imkonini xam beradi. Rasmni fayldan yuklash uchun imageicon klassidan foydalaniladi. Masalan: import java.awt.*;
JButton klassi yordamida yaratilgan tugma import javax.swing.*;
public class RasmliTugma{ public static void main(String[] args){ JFrame frame = new JFrame(); JPanel panel = new JPanel(); Icon icon = new ImageIcon("search.png"); JButton button = new JButton("OK", icon); panel.add(button) ; frame.getContentPane() .add(panel); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE) ; frame.setSize(300,200); frame .setVisible(true); } }
JButton
klassi yordamida yaratilgan rasmli tugma Java dasturlash tilida tugma bosilganda ActionEvent xodisasi xosil qilinadi. Ushbu xodisani qabul qilish uchun dastur xodisalarni nazorat qiluvchi ActionListener interfeysini bajarishi va uning
actionPerformed() metodini qayta yaratishi kerak bo’ladi. actionPerformed() metodi
ichiga tugma bosilganda bajarilishi kerak bo’ladigan amallar kiritiladi. Masalan: import java.awt.*; import java.awt.event.*; import javax.swing.*; public class TugmaAmali { JPanel panel; Color backgroundColor = Color.YELLOW; String tugmaMatni = "Sariq"; public static void main(String[] args) {
JButton button;
TugmaAmali ta = new TugmaAmali(); ta.go(); } public void go() { JFrame frame = new JFrame("TugmaAmali"); panel = new JPanel(); panel.setBackground(backgroundColor); button = new JButton(tugmaMatni); button.addActionListener(new ButtonListener()); panel.add(button); frame.getContentPane().add(panel); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE) ; frame.setSize(300,200); frame.setVisible(true); } public class ButtonListener implements ActionListener { public void actionPerformed(ActionEvent e) { if(backgroundColor == Color.YELLOW) { backgroundColor = Color.RED; tugmaMatni = "Qizil"; }else{
backgroundColor = Color.YELLOW; tugmaMatni = "Sariq"; } panel.setBackground(backgroundColor); button.setText(tugmaMatni);
} Yuqoridagi dastur tugma bosilganda oyna rangi sariq rangdan qizil rangga o’zgaradi.
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