JLabel和JTextArea无法正常工作

Question

I am making a window that has a large text area and a small text area under it. This is what i have so far:

This is the code I have for it:

JPanel window=new JPanel(){
    protected void paintComponent(Graphics g){
        super.paintComponent(g);
        ImageIcon ii=new ImageIcon("textEffect.png");
        Image i=ii.getImage();
        g.drawImage(i,0,0,null,this);
    }
};
JLabel label=new JLabel("Say: ");
JTextArea dialog=new JTextArea(20,50);
JTextArea input=new JTextArea(1,46);
JScrollPane scroll=new JScrollPane(
    dialog,
    JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
    JScrollPane.HORIZONTAL_SCROLLBAR_NEVER
);

//main method
public static void main(String[] args){
    new Window();
}
//Makes window and starts bot
public Window(){
    super("Pollockoraptor");
    setSize(600,400);
    setResizable(false);
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    dialog.setEditable(false);
    dialog.setOpaque(false);
    dialog.setBackground(new Color(0, 0, 0, 0));
    dialog.setLineWrap(true);
    input.addKeyListener(this);
    label.setVerticalTextPosition(SwingConstants.BOTTOM);
    label.setHorizontalTextPosition(SwingConstants.LEFT);
    window.add(scroll);
    window.add(label);
    window.add(input);
    window.setBackground(new Color(97,118,131));
    add(window);
    setVisible(true);
}'

How do I make the larger textarea partially transparent so I can see the background and how do I move "Say:" to be infront of the smaller textarea?

Answer 1

JPanel uses a FlowLayout by default. You'll want to change the layout manager, personally, I'd recommend something like GridBagLayout , but that's just me.

See Laying Out Components Within a Container for more details

To make the JTextArea see through, you're going to have to make the JScrollPane and it's JViewPort transparent as well.

Swing only knows how to paint fully opaque or fully transparent components. You can create a translucent effect by making the component transparent and overriding it's paintComponent method and using an AlphaComposite or painting a with a Color which has an alpha value set to something below 255

For example...

• Can not draw image on JTextArea background when using Nimbus Look And Feel
• JTextArea not selectable, but still showing a "ghost" cursor
• Swing Graphics on JFrame

And general advice...

• Key Bindings over KeyListener
• Override getPreferredSize of your custom component to get better results when been laid out
• Use JFrame#pack over setSize , this will calculate the window size based on the needs of the content and take into account the window frame decorations as well

Answer 2

How do I make the larger textarea partially transparent so I can see the background

Check out Backgrounds With Transparency for problems when using a transparent background and a general purpose solution you can use to you don't need to do custom painting all the time.