Ukuze sixazulule le nkinga, sizosebenzisa ulimi lohlelo lwe-Java futhi sisebenze namalabhulali alo ahlobene nezingxenye ze-UI. Sizohamba ekusetshenzisweni kwekhodi, sidingida imisebenzi eyahlukene nemitapo yolwazi ehilelekile kule nqubo. Ekupheleni kwalesi sihloko, uzothola ukuqonda okujulile kokuthi ungayithola kanjani inkomba ekhethiwe ku-ListView ku-Java.
I-Java Swing kanye ne-ListView Components
I-Java Swing iqoqo lemitapo yolwazi ye-Java ehlinzeka nge-GUI (I-Graphical User Interface) nezinye izingxenye ze-UI zezinhlelo zokusebenza ze-Java. I-Swing inikeza izingxenye ze-UI ezihlukahlukene ezibizwa amawijethi ongazisebenzisa ezinhlelweni zakho zokusebenza, njengezinkinobho, amalebula, izinkambu zombhalo, kanye ne-ListView. Ingxenye ye-ListView ku-Java Swing yaziwa ngokuthi JList.
Manje, ake singene enkingeni yethu enkulu: ukuthola inkomba ekhethiwe yento ekhethiwe ku-ListView.
import javax.swing.*; import java.awt.event.*; public class ListViewExample { public static void main(String[] args) { JFrame frame = new JFrame("ListView Example"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); frame.setSize(300, 200); DefaultListModel<String> listModel = new DefaultListModel<>(); listModel.addElement("Item 1"); listModel.addElement("Item 2"); listModel.addElement("Item 3"); JList<String> listView = new JList<>(listModel); JScrollPane scrollPane = new JScrollPane(listView); listView.addListSelectionListener(new ListSelectionListener() { public void valueChanged(ListSelectionEvent e) { if (!e.getValueIsAdjusting()) { int selectedIndex = listView.getSelectedIndex(); System.out.println("Selected index: " + selectedIndex); } } }); frame.getContentPane().add(scrollPane); frame.setVisible(true); } }
Kukhodi engenhla, siqala ngokungenisa imitapo yolwazi edingekayo ye-Java Swing kanye namakilasi okusingatha umcimbi. Okulandelayo, sakha i-JFrame elula ene- JList ingxenye yokudala i-ListView yethu.
Ukuphathwa Komcimbi kanye ne-ListSelectionListener
Ukuze uthole inkomba ekhethiwe ku-JList, kufanele sisebenzise isibambi somcimbi. Ku-Java Swing, ukuphatha umcimbi kwenziwa ngomqondo wokuthi abalaleli. Abalaleli bayizixhumanisi ze-Java ezichaza izindlela zokusingatha imicimbi ethile. Esimweni sethu, sisebenzisa i- ListSelectionListener isikhombimsebenzisi sokusingatha umcimbi wokukhetha uhlu.
Isixhumi esibonakalayo se-ListSelectionListener sinendlela eyodwa ebizwa ngokuthi valueChanged(ListSelectionEvent e). Le ndlela ibizwa noma nini lapho umsebenzisi ekhetha noma eyeka ukukhetha into yohlu ku-ListView. Endleleni ye-valueChanged, siqale sihlole ukuthi inqubo yokulungisa inani iphelele yini e.getValueIsAdjusting() ukugwema ukuthola imicimbi eyimpinda, bese uthola inkomba ekhethiwe usebenzisa listView.getSelectedIndex().
Ngemva kokusebenzisa ukuphatha umcimbi, inkomba ekhethiwe yento ekhethiwe iphrintwa kukhonsoli lapho umsebenzisi achofoza entweni eku-ListView.
Sengiphetha, sihambe ngenqubo yokuthola inkomba ekhethiwe ku-ListView ku-Java, sisebenzisa ingxenye ye-JList ye-Java Swing futhi sisebenzisa ukuphathwa kwemicimbi ngokusebenzisa i-ListSelectionListener interface. Le ncazelo enemininingwane, ehambisana nemitapo yolwazi nemisebenzi ehilelekile, izoba usizo ekubhekaneni nezinkinga ezifanayo futhi inothise ulwazi lwakho lohlelo lwe-Java.