Question

我正在尝试将图像放在JLabel上，但我无法获得宽度或高度。我认为因为jLabel1没有实例化。但我画了设计小组。无论如何我该怎么做？

我创建了JFrame，JPanel（jPanel1）和JLabel（jLabel1）。（关于netbeans）

这是我的代码：

public class ImageProcessing extends javax.swing.JFrame {

    Image image;

    public ImageProcessing() {

        setSize(640, 480);
        setVisible(true);
        ImageIcon icon = new ImageIcon("D:\\timeline.jpg");
        image = icon.getImage();
        Image newImg = image.getScaledInstance(jLabel1.getHeight(), jLabel1.getWidth(), java.awt.Image.SCALE_SMOOTH);
        ImageIcon i1 = new ImageIcon(newImg);
        jLabel1 = new JLabel(i1);

        getContentPane().add(jLabel1);
}

Answer 1

这应该可以正常工作

import java.awt.Dimension;
import java.awt.Image;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;

public class ImageProcessing extends JFrame {

    private JLabel jLabel1;
    private JPanel jPanel1;

    public ImageProcessing() {

        initComponents();
        ImageIcon icon = new ImageIcon("D:\\timeline.jpg");
        Image scaledInstance = icon.getImage().getScaledInstance(jLabel1.getWidth(), jLabel1.getHeight(), Image.SCALE_SMOOTH);
        ImageIcon scaledIcon = new ImageIcon(scaledInstance);
        jLabel1.setIcon(scaledIcon);

        this.setSize(new Dimension(1024, 768));
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setVisible(true);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {

            @Override
            public void run() {
                new ImageProcessing();
            }
        });
    }

    private void initComponents() {

        jPanel1 = new javax.swing.JPanel();
        jLabel1 = new javax.swing.JLabel();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 604, Short.MAX_VALUE)
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGap(0, 351, Short.MAX_VALUE)
        );

        jLabel1.setText("Label");

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(139, 139, 139)
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 493, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED)
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE))
        );
        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(52, 52, 52)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 226, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap(144, Short.MAX_VALUE))
        );

        pack();
    }// </editor-fold>                        
}

获得JLabel大小

1 个答案: