Question

我不明白为什么最后一部分没有添加到我的界面。我尝试了不同的方法，但似乎没有一种方法可行。我无法通过这种方式向我的面板添加1024个标签。我做错了什么，或者有替代方法吗？可以告诉我代码有什么问题吗？谢谢！

完整代码：

import java.awt.EventQueue;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextPane;
import javax.swing.border.TitledBorder;
import javax.swing.UIManager;
import javax.swing.JButton;
import javax.swing.JScrollPane;
import javax.swing.JLabel;
import javax.swing.JTextField;
import javax.swing.SwingConstants;

import java.awt.Color;
import java.awt.Font;
import java.awt.GridLayout;
import javax.swing.border.LineBorder;


public class CacheGUI extends JFrame {
    private static final int LEN = 1024;
    private static final long serialVersionUID = 1L;
    private JTextField textField;

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    CacheGUI frame = new CacheGUI();
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    public CacheGUI() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 700, 500);
        getContentPane().setLayout(null);

        JPanel panel = new JPanel();
        panel.setBorder(new TitledBorder(UIManager.getBorder("TitledBorder.border"), "Lista de referinte", TitledBorder.LEADING, TitledBorder.TOP, null, null));
        panel.setBounds(6, 16, 124, 364);
        getContentPane().add(panel);
        panel.setLayout(null);

        JScrollPane scrollPane = new JScrollPane();
        scrollPane.setBounds(6, 16, 108, 340);
        panel.add(scrollPane);

        JTextPane txtpnDasd = new JTextPane();
        txtpnDasd.setToolTipText("Lista curenta de adrese");
        txtpnDasd.setEnabled(false);
        txtpnDasd.setEditable(false);
        scrollPane.setViewportView(txtpnDasd);
        txtpnDasd.setText("<generate first>");

        JButton btnGenerate = new JButton("GENERATE");
        btnGenerate.setToolTipText("Incepe generarea listei de adrese.");
        btnGenerate.setBounds(6, 422, 124, 23);
        getContentPane().add(btnGenerate);

        JButton btnStart = new JButton("START");
        btnStart.setToolTipText("Ruleaza simularea");
        btnStart.setBounds(550, 422, 124, 23);
        getContentPane().add(btnStart);

        JLabel lblBlockSize = new JLabel("Block size:");
        lblBlockSize.setFont(new Font("Tahoma", Font.BOLD, 12));
        lblBlockSize.setBounds(6, 394, 85, 14);
        getContentPane().add(lblBlockSize);

        textField = new JTextField();
        textField.setToolTipText("");
        textField.setHorizontalAlignment(SwingConstants.CENTER);
        textField.setText("4");
        textField.setBounds(79, 391, 51, 20);
        getContentPane().add(textField);
        textField.setColumns(10);

        int blocksize = Integer.parseInt(textField.getText());
        int nrofblocks = LEN/blocksize;  // LEN is 1024 

        JPanel block_panel = new JPanel();
        block_panel.setBorder(new TitledBorder(null, "", TitledBorder.LEADING, TitledBorder.TOP, null, null));
        block_panel.setBounds(140, 16, 534, 398);
        getContentPane().add(block_panel);
        block_panel.setLayout(new GridLayout(blocksize,nrofblocks,2,0));

        // THIS IS THE PART THAT DOES NOT ADD TO THE PANEL I CREATED BEFORE --->
        JLabel[] lbl=new JLabel[LEN]; 
        for(int i=0;i<LEN;i++)
        {
            lbl[i]=new JLabel("TEST");
            lbl[i].setBackground(Color.YELLOW);
            lbl[i].setBorder(new LineBorder(new Color(0, 0, 0), 1, true));
            block_panel.add(lbl[i]); // i want to create yellow blocks inside my panel as labels to modyfy the color afterwards
        }//<----
    }
    }

Answer 1

问题是你拥有的标签数量太多了;他们在那里。

将块面板的边界设置为更大的值，减少LEN等，你会看到它们。

Answer 2

首先要做的事：您的标签不会有黄色背景颜色。默认情况下，JLabel不是不透明的。将其设置为true将显示黄色背景：

lbl[i].setOpaque(true);

第二件事是你拥有的标签数量。将数字减少到100说，你会看到你的标签。

    for(int i=0;i<100;i++)
    {
        lbl[i]=new JLabel("TEST");
        lbl[i].setBackground(Color.YELLOW);
        lbl[i].setBorder(new LineBorder(new Color(0, 0, 0), 1, true));
        lbl[i].setOpaque(true);
        block_panel.add(lbl[i]);
    }

Answer 3

使用JScrollPane，设置不透明，网格布局1.rows，2.columns，为标签设置固定大小，使用BorderFactory。

    JPanel block_panel = new JPanel();
    block_panel.setBorder(new TitledBorder(null, "", TitledBorder.LEADING,
            TitledBorder.TOP, null, null));
    block_panel.setBounds(140, 16, 534, 398);
    JScrollPane block_scrollpane = new JScrollPane(block_panel);
    block_scrollpane.setBounds(140, 16, 534, 398);
    getContentPane().add(block_scrollpane);
    //block_panel.setLayout(new GridLayout(blocksize, nrofblocks, 2, 0));
    block_panel.setLayout(new GridLayout(nrofblocks, blocksize, 2, 0));

    // THIS IS THE PART THAT DOES NOT ADD TO THE PANEL I CREATED BEFORE --->
    JLabel[] lbl = new JLabel[LEN];
    Dimension lblSize = new Dimension(85, 16);
    for (int i = 0; i < LEN; i++) {
        lbl[i] = new JLabel("TEST" + i);
        lbl[i].setOpaque(true);
        lbl[i].setBackground(Color.YELLOW);
        lbl[i].setBorder(BorderFactory.createLineBorder(Color.BLACK, 1, true));
        lbl[i].setPreferredSize(lblSize);
        lbl[i].setMinimumSize(lblSize);
        block_panel.add(lbl[i]); // i want to create yellow blocks
                   // inside my panel as labels to modyfy the color afterwards
    }//<----

无法在JPanel中创建JLabel

3 个答案: