I want to enter text into my fourth JPanel, and every time I hit enter to update the first JPanel with the text. I added a keylistener for the return key, it runs a function in the inner class AddSong, that function takes in an arraylist of text, and returns a string. I want to display that string on the JPanel in the first quadrent, but it doesn't work. Right now I believe it is removing the first JPanel, and not updating. I am very confused because this is my first encounter with key events as I am new to programming.
Here's the code:
public class MusicPlayer extends JFrame{
private static final int WIDTH = 400;
private static final int HEIGHT = 400;
private JLabel songList,songPlaying,c;
private JTextField enterSong;
private AddSong input;
public MusicPlayer(){
//Text box enterSong, input passed to actionListener
input = new AddSong();
enterSong = new JTextField(10);
enterSong.addActionListener(input);
//Numbers the quadrents
songList = new JLabel(input.printSongs(input.songList),SwingConstants.CENTER);
songPlaying = new JLabel("2",SwingConstants.CENTER);
c = new JLabel("c",SwingConstants.CENTER);
//Makes and sets size of pane
Container pane = getContentPane();
pane.setLayout(new GridLayout(2,2));
//Add JLabels to panes in the container
pane.add(songList);
pane.add(songPlaying);
pane.add(c);
pane.add(enterSong);
//KeyListener - return
addKeyListener(new KeyListener() {
@Override
public void keyPressed(KeyEvent ke){}
@Override
public void keyReleased(KeyEvent ke){}
@Override
public void keyTyped(KeyEvent ke){
if(ke.getKeyCode()==KeyEvent.VK_ENTER){
input.printSongs(input.songList);
}
}
});
add(songList);
pack();
setTitle("Andrew's Music Player");
setSize(WIDTH,HEIGHT);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public class AddSong implements ActionListener{
//List of Songs
ArrayList<String> songList = new ArrayList<String>();
String display;
public AddSong(){
display = "";
}
public void actionPerformed(ActionEvent e){
String song;
//get the text
song = enterSong.getText();
//add current text string to list
songList.add(song);
//print songlist
System.out.print(printSongs(songList));
}
public String printSongs(ArrayList<String> songList){
display = "";
for(int i = 0; i < songList.size(); i++){
display += songList.get(i) + "\n";
}
return display;
}
}
public static void main(String args[]){
MusicPlayer boi = new MusicPlayer();
}
}
Welcome to SO. Having a action listener, you can drop the key listener.
Please note the comments :
public class MusicPlayer extends JFrame{
private static final int WIDTH = 400;
private static final int HEIGHT = 400;
private JLabel songsList,songPlaying,c;
private JTextField enterSong;
private AddSong input;
public MusicPlayer(){
//Text box enterSong, input passed to actionListener
input = new AddSong();
enterSong = new JTextField(10);
enterSong.addActionListener(input);
//Numbers the quadrents
songsList = new JLabel("No songs in list",SwingConstants.CENTER);
songPlaying = new JLabel("2",SwingConstants.CENTER);
c = new JLabel("c",SwingConstants.CENTER);
//Makes and sets size of pane
Container pane = getContentPane();
pane.setLayout(new GridLayout(2,2));
//Add JLabels to panes in the container
pane.add(songsList);
pane.add(songPlaying);
pane.add(c);
pane.add(enterSong);
//adding a key listenr to the Jframe is not need
//the enterSong.addActionListener(input); does the work
add(songsList);
pack();
setTitle("Andrew's Music Player");
setSize(WIDTH,HEIGHT);
setVisible(true);
setDefaultCloseOperation(EXIT_ON_CLOSE);
}
public class AddSong implements ActionListener{
//List of Songs
ArrayList<String> songList = new ArrayList<>();
public AddSong(){ }
@Override
public void actionPerformed(ActionEvent e){
String song;
//get the text
song = enterSong.getText();
//add current text string to list
songList.add(song);
String songListAsString = printSongs(songList);
//update display with new song
songsList.setText(songListAsString);
//clear text field
enterSong.setText("");
}
public String printSongs(ArrayList<String> songList){
//using string builder is more efficient
//to have multiple lines in a JLabel you have to use
//html tags
//a JList would be more appropriiate
StringBuilder sb = new StringBuilder("<html>");
for(int i = 0; i < songList.size(); i++){
sb.append("<p>")
.append(songList.get(i))
.append("</p>");
}
sb.append("</html>");
return sb.toString();
}
}
public static void main(String args[]){
MusicPlayer boi = new MusicPlayer();
}
}