setLocation of Label

Question

我让所有标签都正常工作,但userLabel [3]无法正确定位无论我做什么,标签"颜色:"始终显示在x坐标为0且y坐标为0的框架上在框架的一半.

    JLabel[] userLabel = new JLabel[4];
    for(int p = 0; p < userLabel.length; p++){
        userLabel[p] = new JLabel();
        userLabel[p].setSize(100,50);
        frameSetUp.add(userLabel[p]);
    }
    userLabel[0].setText("Width of Frame:");
    userLabel[1].setText("Height of Frame:");
    userLabel[2].setText("# OF Balls:");
    userLabel[3].setText("Color:");

    userLabel[0].setLocation(10,35);
    userLabel[1].setLocation(10,85);
    userLabel[2].setLocation(10,135);
    userLabel[3].setLocation(0,0); //no matter what coordinates I change this too, it wont reposition

图片:[IMG] http://i41.tinypic.com/23jfo9l.png [/ IMG] http://i41.tinypic.com/23jfo9l.png

Answer 1

1. 不要使用setLocation,setBounds,null布局或绝对定位.
2. 而是使用布局管理器,包括可能嵌套的JPanels,每个都使用自己的布局管理器来实现令人满意的易于维护的GUI.
3. 如需更多帮助,请展示您正在尝试实现的目标,实际实现的目标,并发布最小的工作示例,代码小,编译和运行,并向我们展示您的问题.

例如,

import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import java.awt.Insets;
import java.util.HashMap;
import java.util.Map;

import javax.swing.*;

@SuppressWarnings("serial")
public class InputForm extends JPanel {
   private static final int COLUMNS = 10;
   private static final int GAP = 3;
   private static final Insets LABEL_INSETS = new Insets(GAP, GAP, GAP, 15);
   private static final Insets TEXTFIELD_INSETS = new Insets(GAP, GAP, GAP, GAP);
   private String[] labelTexts;
   private Map<String, JTextField> fieldMap = new HashMap<String, JTextField>();

   public InputForm(String[] labelTexts) {
      this.labelTexts = labelTexts;
      setLayout(new GridBagLayout());
      for (int i = 0; i < labelTexts.length; i++) {
         String text = labelTexts[i];
         JTextField field = new JTextField(COLUMNS);
         fieldMap.put(text, field);

         addLabel(text, i);
         addTextField(field, i);
      }
   }

   public String[] getLabelTexts() {
      return labelTexts;
   }

   private void addTextField(JTextField field, int row) {
      GridBagConstraints gbc = new GridBagConstraints();
      gbc.gridwidth = 1;
      gbc.gridheight = 1;
      gbc.gridx = 1;
      gbc.gridy = row;
      gbc.anchor = GridBagConstraints.EAST;
      gbc.fill = GridBagConstraints.HORIZONTAL;
      gbc.insets = TEXTFIELD_INSETS;
      gbc.weightx = 1.0;
      gbc.weighty = 1.0;
      add(field, gbc);
   }

   private void addLabel(String text, int row) {
      GridBagConstraints gbc = new GridBagConstraints();
      gbc.gridwidth = 1;
      gbc.gridheight = 1;
      gbc.gridx = 0;
      gbc.gridy = row;
      gbc.anchor = GridBagConstraints.WEST;
      gbc.fill = GridBagConstraints.BOTH;
      gbc.insets = LABEL_INSETS;
      gbc.weightx = 1.0;
      gbc.weighty = 1.0;
      add(new JLabel(text), gbc);
   }

   public String getFieldText(String key) {
      String text = "";
      JTextField field = fieldMap.get(key);
      if (field != null) {
         text = field.getText();
      }
      return text;
   }

   private static void createAndShowGui() {
      String[] labelTexts = new String[] { "Width of Frame:",
            "Height of Frame:", "# OF Balls:", "Color:" };
      InputForm inputForm = new InputForm(labelTexts);

      int result = JOptionPane.showConfirmDialog(null, inputForm, "Input Form",
            JOptionPane.OK_CANCEL_OPTION, JOptionPane.PLAIN_MESSAGE);
      if (result == JOptionPane.OK_OPTION) {
         for (String text : labelTexts) {
            System.out.printf("%20s %s%n", text, inputForm.getFieldText(text));
         }
      }
   }

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

这将显示如下:

这段代码的美妙之处在于,如果你想添加另一个字段,比如一个行厚度字段,并希望添加它以使其倒数第二,那么代码所需的唯一更改就是更改它:

  String[] labelTexts = new String[] { "Width of Frame:",
        "Height of Frame:", "# OF Balls:", "Color:" };

对此:

  String[] labelTexts = new String[] { "Width of Frame:",
        "Height of Frame:", "# OF Balls:", "Line Thickness:", "Color:" };

结果如下:

无需计算如何更改Color标签或JTextField的位置,因为布局管理器会为您完成所有艰苦的工作.