java - 我怎样才能使黑色在上传的图像之上透明？

Question

现在我所拥有的只是创建黑色背景并上传我想要的图像。我想使图像位于透明背景后面。我最初将所有这些都放在单独的类文件中，但将它们全部放在一个主类中

package Flashlight;

    import java.awt.Color;
    import java.awt.GridLayout;
    import java.awt.event.ActionEvent;
    import java.awt.event.ActionListener;
    import javax.swing.ImageIcon;
    import javax.swing.JButton;
    import javax.swing.JFrame;
    import javax.swing.JLabel;
    import javax.swing.JPanel;

    public class Flashlight3 extends JFrame {

        public class FlashLabelChange extends JPanel {

            Flashlight.FlashDisp flashDisp;

            public FlashLabelChange(Flashlight.FlashDisp _flashDisp) {
                flashDisp = _flashDisp;
                JButton btn1 = new JButton("Start");
                add(btn1);
                class Button implements ActionListener {

                    public void actionPerformed(ActionEvent event) {
                        if (event.getActionCommand().equals("Start")) {
                            flashDisp.UpdateLabel("Start");
                        }
                    }
                }
                ActionListener button = new Button();
                btn1.addActionListener(button);

            }
        }

        public class FlashDisp extends JPanel {

            private JLabel lblName;
            private String sLabel;
            private JLabel lblImage;

            public FlashDisp() {
                lblImage = new JLabel();
                add(lblImage);
                lblName = new JLabel("Start?");
                add(lblName); //add it to the Frame
            }

            void UpdateLabel(String _sNew) {
                sLabel = _sNew;
                lblName.setText(sLabel);
            }

            void UpdateBackground(String _sNew) {
                sLabel = _sNew;
                if (sLabel == ("Black")) {
                    setBackground(Color.black);
                    lblImage.setIcon(new ImageIcon("Hallway.png"));
                }
            }
        }

        public class FlashColour extends JPanel {

            FlashDisp flashDisp;

            public FlashColour(FlashDisp _flashDisp) {
                flashDisp = _flashDisp;
                setLayout(new GridLayout(3, 1));
                JButton btnDark = new JButton("Dark");
                add(btnDark);
                class ColourChangeListener implements ActionListener {

                    public void actionPerformed(ActionEvent event) {
                        if (event.getActionCommand().equals("Dark")) {
                            flashDisp.UpdateBackground("Black");
                        }
                    }
                }
                ActionListener colourChangeListener = new ColourChangeListener();
                btnDark.addActionListener(colourChangeListener);


            }
        }

        public static void main(String[] args) {
            JFrame frame = new JFrame();
            FlashMain flashMain = new FlashMain();
            frame.setSize(400, 400);
            frame.setTitle("FLAAAASH LIGHT");
            frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
            frame.add(flashMain);
            frame.setVisible(true);
        }
    }

Answer 1

我认为您需要使用opaque 方法。

看这里 setOpaque(true/false); Java使用不透明。

希望对您有所帮助。