背景图像隐藏了其他组件，如按钮标签等，反之亦然

Question

如何解决这段代码中隐藏组件的问题
代码运行没有错误
但是没有显示背景图片
如何修改代码获取背景图片

当使用验证方法时，它在 validation() 中创建错误

   public class TEST{
    public TEST() {  
      String[] strm = {"Jan", "Feb", "Mar", "Apr", "May"};
       String[] stry = {"2016", "2017", "2018","2019"};
       String[] strf={"NEW Delhi", "Bangalore", "Chennai"};
       String[] strt={"Goa","Kashmir","Hyderabad"};
       JFrame f = new JFrame("test");
       f.setSize(500, 500);
       f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
       JLabel lfr = new JLabel("FROM");
       JLabel lto = new JLabel("TO");
       JLabel lda = new JLabel("DATE");
       JLabel ld = new JLabel("DAY");
       JLabel lm = new JLabel("MONTH");
       JLabel y = new JLabel("YEAR");
       JComboBox cfr = new JComboBox(strf);
       JComboBox cto = new JComboBox(strt);
       JComboBox cd = new JComboBox();
       JComboBox cm = new JComboBox(strm);
       JComboBox cy = new JComboBox(stry);
       JButton bs = new JButton("Search");
       JPanel p1 = new JPanel(null);
       p1.setPreferredSize(new Dimension(500,500));
       JLabel jimage = new JLabel();
       jimage.setIcon(new ImageIcon("air.jpg"));


       for(int i = 1; i <= 31; i++)
           cd.addItem(i);
       lfr.setBounds(20, 40, 100, 20);
       cfr.setBounds(100, 40, 100, 20);
       lto.setBounds(20, 100, 25, 20);
       cto.setBounds(100, 100, 100, 20);
       lda.setBounds(20, 160, 50, 20);
       cd.setBounds(100, 160, 50, 20);
       cm.setBounds(160, 160, 65, 20);
       cy.setBounds(240, 160, 75, 20);
       ld.setBounds(100, 190, 50, 20);
       lm.setBounds(160, 190, 50, 20);
       y.setBounds(240, 190, 50, 20);
       bs.setBounds(20, 230, 100, 20);
       p1.add(lfr);
       p1.add(cfr);
       p1.add(lto);
       p1.add(cto);
       p1.add(lda);
       p1.add(cd);
       p1.add(cm);
       p1.add(cy);
       p1.add(ld);
       p1.add(lm);
       p1.add(y);
       p1.add(bs);
       p1.add(jimage);
      // validate();

       f.add(p1);

       f.setVisible(true);
    }

  public static void main(String[] args) {
      new TEST();
  }

}

Answer 1

你能做的最好的事情是：

import java.awt.FlowLayout;
import java.awt.GridLayout;

import javax.swing.BoxLayout;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;

public class Test {
    JLabel label;
    JComboBox combo;
    JButton button;
    JPanel pane;
    JFrame frame;

    JPanel create1stRow() {
        JPanel pane = new JPanel();
        pane.setLayout(new FlowLayout(FlowLayout.LEFT));
        pane.setOpaque(false);
        String options[] = {"New Delhi", "Bangalore", "Chennai"};
        label = new JLabel("FROM");
        combo = new JComboBox(options);

        pane.add(label);
        pane.add(combo);
        return pane;
    }

    JPanel create2ndRow() {
        JPanel pane = new JPanel();
        pane.setLayout(new FlowLayout(FlowLayout.LEFT));
        pane.setOpaque(false);
        String options[] = {"Goa", "Kashmir", "Hyderabad"};
        label = new JLabel("TO");
        combo = new JComboBox(options);

        pane.add(label);
        pane.add(combo);
        return pane;
    }

    JPanel create3rdRow() {
        JPanel pane = new JPanel();
        JPanel dataPane = new JPanel();
        pane.setLayout(new FlowLayout(FlowLayout.LEFT));
        pane.setOpaque(false);
        dataPane.setOpaque(false); //forgot to add this line when I took the pic
        dataPane.setLayout(new GridLayout(2, 3)); //2 rows, 3 cols, so we can have the combos with their text aligned

        String days[] = {"1", "2", "3", "4", "5"}; //Too lazy to write 31 days
        String months[] = {"Jan", "Feb", "Mar", "Apr", "May"}; //Too lazy to write 12 months
        String years[] = {"2016", "2017", "2018", "2019", "2020"};
        label = new JLabel("DATE");
        combo = new JComboBox(days);

        //We add the combos
        dataPane.add(combo);
        combo = new JComboBox(months); //We're reusing the object, but change the data
        dataPane.add(combo);
        combo = new JComboBox(years); //The same as above
        dataPane.add(combo);

        //Now we add the labels
        dataPane.add(new JLabel("DAYS"));
        dataPane.add(new JLabel("MONTHS"));
        dataPane.add(new JLabel("YEARS"));

        pane.add(label);
        pane.add(dataPane); //We add the whole pane to another one
        return pane;
    }

    JPanel create4thRow() {
        JPanel pane = new JPanel();
        pane.setLayout(new FlowLayout(FlowLayout.LEFT));
        pane.setOpaque(false);
        button = new JButton("Search");

        pane.add(button);
        return pane;
    }

    public Test() {
        frame = new JFrame("Test");
        frame.setContentPane(new JLabel(new ImageIcon("C:/Users/Frakcool/workspace/WhosebugProjects/src/test/Air.jpg")));
        frame.getContentPane().setLayout(new BoxLayout(frame.getContentPane(), BoxLayout.PAGE_AXIS));

        pane = create1stRow();
        frame.add(pane);
        pane = create2ndRow();
        frame.add(pane);
        pane = create3rdRow();
        frame.add(pane);
        pane = create4thRow();
        frame.add(pane);

        frame.pack();
        //frame.setSize(500, 500); //If your image is too large use this
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }

    public static void main (String args[]) {
        new Test();
    }
}

正如你在上面的代码中看到的，我没有使用一个 null layout 而是多个 Layout Managers 的组合，我建议你以后这样做。

但如果您仍想使用那个丑陋的 null 布局，您就错过了这一行：

jimage.setBounds(0, 0, 500, 500);

在此之前：

lfr.setBounds(20, 40, 100, 20);

我上面的代码给出的输出是：

你的代码用我添加的行给出的输出是：

如您所见，两者非常相似，我本可以完全相同，但我没有足够的时间这样做，但您可以结合我在上面发布的布局管理器。

注意：我忘了说要让这个程序显示背景图片，我需要用 pane.setOpaque(false); 使每个其他面板不透明所以，每当您需要显示另一个面板后面的内容时，请务必使用它。

背景图像隐藏了其他组件，如按钮标签等，反之亦然

background image hidding the other components like buttons labels and other, and vicce versa

java

swing

jlabel