Impossibile modificare la dimensione del blocco in BorderLayout

Question

Ho creato un'app semplice con Border Layout e ho aggiunto due pulsanti e JTable. Io uso JSplitPane tra button2 e JTable. Vorrei ridefinire la dimensione predefinita del blocco in cui si trova button1. Come posso risolvere questo compito?

Qui è il mio codice:

package test; 

import java.awt.BorderLayout; 
import java.awt.Dimension; 
import javax.swing.JButton; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 
import javax.swing.JSplitPane; 
import javax.swing.JTable; 
import javax.swing.SwingUtilities; 

public class Sample { 

    public Sample() { 
     JFrame app = new JFrame("Sample"); 
     app.setSize(new Dimension(800,600)); 

     JPanel panel = new JPanel(); 
     app.add(panel); 

     BorderLayout borderlayout = new BorderLayout(); 
     panel.setLayout(borderlayout); 

     JButton but1 = new JButton("1"); 
     JButton but2 = new JButton("2"); 
     but2.setMinimumSize(new Dimension(250,0)); 
     String[] colNames = {"Name","Number","Scores"}; 
     Object[][] data = { 
       { "Mark",11,12}, 
       {"Tommy",23,34}, 
       {"John",34,45} 
     }; 
     JTable table = new JTable(data, colNames); 

     JScrollPane scrollpane = new JScrollPane(table); 
     JSplitPane jsplitpane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,but2,scrollpane); 

     panel.add(but1,BorderLayout.NORTH); 
     panel.add(jsplitpane,BorderLayout.CENTER); 

     app.setVisible(true); 
    } 

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

Answer 1

Se siete disposti ad utilizzare GridBagLayout per detto scopo, allora credo che questo Layout e fare questo lavoro per voi, come indicato nel seguente esempio di codice incollato :-)

import java.awt.BorderLayout; 
import java.awt.GridLayout; 
import java.awt.GridBagConstraints; 
import java.awt.GridBagLayout; 
import java.awt.Dimension; 
import javax.swing.BorderFactory; 
import javax.swing.JButton; 
import javax.swing.JFrame; 
import javax.swing.JPanel; 
import javax.swing.JScrollPane; 
import javax.swing.JSplitPane; 
import javax.swing.JTable; 
import javax.swing.SwingUtilities; 

public class Sample { 

    public Sample() { 
     JFrame app = new JFrame("Sample"); 
     app.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE); 
     app.setSize(new Dimension(800,600)); 

     JPanel panel = new JPanel(); 
     panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5)); 
     panel.setLayout(new BorderLayout(5, 5)); 
     JPanel centerPanel = new JPanel(); 
     centerPanel.setLayout(new GridBagLayout());   

     JButton but1 = new JButton("1"); 
     JButton but2 = new JButton("2"); 
     but2.setMinimumSize(new Dimension(250,0)); 
     String[] colNames = {"Name","Number","Scores"}; 
     Object[][] data = { 
       { "Mark",11,12}, 
       {"Tommy",23,34}, 
       {"John",34,45} 
     }; 
     JTable table = new JTable(data, colNames); 

     JScrollPane scrollpane = new JScrollPane(table); 
     JSplitPane jsplitpane = new JSplitPane(JSplitPane.HORIZONTAL_SPLIT,but2,scrollpane); 

     GridBagConstraints gbc = new GridBagConstraints(); 
     gbc.anchor = GridBagConstraints.FIRST_LINE_START; 
     gbc.fill = GridBagConstraints.BOTH; 
     gbc.gridx = 0; 
     gbc.gridy = 0; 
     gbc.weightx = 1.0; 
     gbc.weighty = 0.3; 

     centerPanel.add(but1, gbc);   

     gbc.fill = GridBagConstraints.BOTH; 
     gbc.gridy = 1; 
     gbc.weighty = 0.7; 

     centerPanel.add(jsplitpane, gbc); 

     panel.add(centerPanel, BorderLayout.CENTER); 

     app.add(panel); 
     app.setVisible(true); 
    } 

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

Qui è l'uscita della stessa:

Answer 2

componenti nella posizione BorderLayout.PAGE_START hanno l'altezza delle loro dimensioni preferite rispettati. Pertanto, è possibile ignorare la dimensione preferita di JButtonbut1

JButton but1 = new JButton("1") { 
    public Dimension getPreferredSize() { 
     return new Dimension(100, 80); 
    }; 
};