如何使 JTextField 透明？

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英文:

How to have a transparent JTextField?

问题

这是我在这里的第一篇帖子，所以如果这不是正确的提问方式，我很抱歉。我想要改进的建议。

谈到问题，我看了一个关于透明JTextField的YouTube视频（https://www.youtube.com/watch?v=2Ruc5rkDg1E），但是相同的代码没有产生相同的输出。

  1. import javax.swing.*;
  2. import java.awt.*;
  4. public class TextField3 {
  5.    public TextField3() {
  6.       ImageIcon icon = new ImageIcon("pic1.jpg");
  8.       Color back = new Color(0, 0, 0, 80);
  9.       Color fore = new Color(255, 255, 255);
  10.       Font font = new Font("Times New Roman", Font.BOLD, 24);
  12.       JFrame f1 = new JFrame("My First TextField");
  13.       f1.setBounds(150, 50, 900, 500);
  14.       f1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  15.       f1.getContentPane().setLayout(null);
  17.       JTextField tf = new JTextField("TextField");
  18.       tf.setBounds(275, 150, 350, 60);
  19.       tf.setHorizontalAlignment(JTextField.CENTER);
  21.       tf.setBackground(back);
  22.       tf.setForeground(fore);
  23.       tf.setFont(font);
  25.       f1.add(tf);
  26.       f1.setVisible(true);
  27.   }
  28.   public static void main(String[] args) {
  29.       TextField3 tf = new TextField3();
  30.   }
  31. }

视频中的输出。

我的输出

上面的代码与视频中的代码不完全相同。实际上，视频中的代码生成了一个空白的JFrame，然后我将代码中的JLabel部分移动到了JFrame的下方，然后才产生了第二张图片中的输出。

我搜索了关于这个问题，并发现将setOpaque设置为false可以解决这个问题。但是当我尝试这样做时，JTextField完全消失，只显示背景图像。有人能帮助解决这个问题吗？

英文:

This is my first post here, so I apologize if this is not the right way to ask. I would like suggestions to improve.

Coming to the question, I saw a youtube video(https://www.youtube.com/watch?v=2Ruc5rkDg1E) about transparent Jtextfield, but the same code isn't giving the same output.

  1.     import javax.swing.*;
  2.     import java.awt.*;
  4.     public class TextField3 {
  5.        public TextField3() {
  6.           ImageIcon icon = new ImageIcon("pic1.jpg");
  7.           //JLabel l1 = new JLabel();
  8.           //l1.setBounds(0, 0, 900, 500);
  9.           //l1.setIcon(icon);
  11.           Color back = new Color(0, 0, 0, 80);
  12.           Color fore = new Color(255, 255, 255);
  13.           Font font = new Font("Times New Roman", Font.BOLD, 24);
  15.           JFrame f1 = new JFrame("My First TextField");
  16.           f1.setBounds(150, 50, 900, 500);
  17.           //f1.setVisible(true);
  18.           f1.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  19.           f1.getContentPane().setLayout(null);
  21.           JLabel l1 = new JLabel();
  22.           l1.setBounds(0, 0, 900, 500);
  23.           l1.setIcon(icon);
  25.           JTextField tf = new JTextField("TextField");
  26.           //tf.setOpaque(false);
  27.           tf.setBounds(275, 150, 350, 60);
  28.           tf.setVisible(true);
  29.           tf.setHorizontalAlignment(JTextField.CENTER);
  31.           tf.setBackground(back);
  32.           tf.setForeground(fore);
  33.           tf.setFont(font);
  35.           f1.add(l1);
  36.           f1.add(tf);
  37.           f1.setVisible(true);
  38.       }
  39.       public static void main(String[] args) {
  40.           TextField3 tf = new TextField3();
  41.       }
  42.     }

The output from the youtube video.

My output

The code above isn't exactly same as the video's code. Actually the code in the video generated a blank JFrame, then I moved the JLabel portion of the code below the JFrame's part, then it produced the output in the 2nd image.

I searched about this issue and found that setOpaque to false will solve this. But when I tried it, the JTextField disappears completely and only the background image is shown. Can someone help in solving this issue?

答案1

得分: 2

Swing设计用于与布局管理器一起使用。您不应该使用null布局，也不应该使用setBounds()方法。

Swing基于父子关系进行设计。如果要让文本字段显示在标签的上方，那么不要将两个组件都添加到框架中。相反，您需要创建这样的结构：

  • 框架
    • 背景标签
      • 文本字段

因此，您的基本代码应该类似于：

  1. JTextField textField = new JTextField("text");
  2. textField.setBackground(...);
  4. JLabel background = new JLabel(...);
  5. background.setLayout(new GridBagLayout());
  6. background.add(textField, new GridBagConstraints());
  8. frame.add(background, BorderLayout.CENTER);

现在您将看到文本字段位于标签的中心。

但是，您仍然会遇到文本字段的半透明背景问题，因为Swing无法正确处理半透明。有关更多信息和解决方案，请查看：https://stackoverflow.com/questions/63362910/why-does-the-alpha-in-this-timer-draw-on-top-of-itself-in-this-java-swing-panel/63364379#63364379

英文:

Swing was designed to be used with layout managers. You should NOT be using a null layout and you should NOT be using setBounds().

Swing is designed on a parent/child relationship. If you want the text field to appear on top of the label then don't add both components to the frame. Instead you need a structure like:

  1. - frame
  2.     - background label
  3.         - text field

So your basic code should be something like:

  1. JTextField textField = new JTextField("text");
  2. textField.setBackground(...);
  4. JLabel background = new JLabel(...);
  5. label.setlayout( new GridBagLayout() );
  6. label.add(textField, new GridBagConstraints());
  8. frame.add(label, BorderLayout.CENTER);

Now you will see the text field in the center of the label.

However, you will still have a problem with the semi-transparent background of the text field, since Swing does not handle semi-transparency properly. For more information and a solution check out: https://stackoverflow.com/questions/63362910/why-does-the-alpha-in-this-timer-draw-on-top-of-itself-in-this-java-swing-panel/63364379#63364379

答案2

得分: 0

你需要使用 setOpaque(false) 方法来使你的 JTextField 变为透明。那应该可以正常工作。

英文:

You need to use setOpaque(false) method to make your JTextField transparent. That should work.

huangapple
  • 本文由 发表于 2020年8月15日 01:33:09
  • 转载请务必保留本文链接：https://go.coder-hub.com/63417528.html
  • java
  • jtextfield
  • swing
  • transparent
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