我尝试在SWING中制作一个简单的应用程序:使用JFrame上的BorderLayout布局,在SOUTH上放置一个执行按钮,在WEST上包含一个组合框的面板上,在EAST上包含2个JTextAreas的面板。问题是,两个JTextArea都太小了。任何帮助和解释都将受到欢迎。
这是具有2个文本区域的面板的代码
package cipher;
import java.awt.Dimension;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.BorderFactory;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.border.Border;
class TextPanel extends JPanel {
private JTextArea inputArea, outputArea;
public TextPanel() {
initSize();
initTextArea();
initBorder();
initLayout();
packing();
}
private void packing() {
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.weightx = 1;
gbc.weighty = 1;
add(inputArea,gbc);
gbc.gridx = 0;
gbc.gridy = 1;
gbc.weightx = 1;
gbc.weighty = 1;
add(outputArea,gbc);
}
private void initBorder() {
Border outer = BorderFactory.createEmptyBorder(5, 5, 5, 5);
Border inner = BorderFactory.createTitledBorder("Text");
setBorder(BorderFactory.createCompoundBorder(outer,inner));
}
private void initLayout() {
setLayout(new GridBagLayout());
}
private void initTextArea() {
inputArea = new JTextArea();
inputArea.setPreferredSize(new Dimension(385,400));
outputArea = new JTextArea();
outputArea.setPreferredSize(new Dimension(385,400));
}
private void initSize() {
Dimension size = getPreferredSize();
size.width = 390;
setPreferredSize(size);
}
}
我尝试使用setSize(x,y),但没有成功。我尝试使用JTextArea(rows,columns)但没有成功。我什至没有使用带有setPreferredSize的Dimension,但是没有成功。
您的问题的可能原因是容器区域小于文本区域的首选大小,然后GridBagLayout
将默认为最小大小。
这是一个很好的示例,说明为什么应避免直接设置这些属性,而要使用布局管理器和组件属性。
首先,使用JTextArea
的column
和rows
属性。这将使显示文本以适应这些限制所需的空间量更好地“猜测”。
第二,使用GridBagConstraints#fill
覆盖GridBagLayout
并强制其利用可用空间
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.GridBagConstraints;
import java.awt.GridBagLayout;
import javax.swing.BorderFactory;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.JTextArea;
import javax.swing.border.Border;
import javax.swing.border.LineBorder;
public class Test {
public static void main(String[] args) {
new Test();
}
public Test() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
JFrame frame = new JFrame();
frame.add(new TextPanel());
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
public class TextPanel extends JPanel {
private JTextArea inputArea, outputArea;
public TextPanel() {
initTextArea();
initBorder();
initLayout();
packing();
}
private void packing() {
GridBagConstraints gbc = new GridBagConstraints();
gbc.gridx = 0;
gbc.gridy = 0;
gbc.weightx = 1;
gbc.weighty = 1;
gbc.fill = GridBagConstraints.BOTH;
add(inputArea, gbc);
gbc.gridx = 0;
gbc.gridy = 1;
gbc.weightx = 1;
gbc.weighty = 1;
gbc.fill = GridBagConstraints.BOTH;
add(outputArea, gbc);
}
private void initBorder() {
Border outer = BorderFactory.createEmptyBorder(5, 5, 5, 5);
Border inner = BorderFactory.createTitledBorder("Text");
setBorder(BorderFactory.createCompoundBorder(outer, inner));
}
private void initLayout() {
setLayout(new GridBagLayout());
}
private void initTextArea() {
// The borders are just here so you can see the different text areas
inputArea = new JTextArea(10, 20);
inputArea.setBorder(new LineBorder(Color.BLACK));
outputArea = new JTextArea(10, 20);
outputArea.setBorder(new LineBorder(Color.BLACK));
}
}
}
我也会改变...
inputArea = new JTextArea(10, 20);
inputArea.setBorder(new LineBorder(Color.BLACK));
outputArea = new JTextArea(10, 20);
outputArea.setBorder(new LineBorder(Color.BLACK));
并使用JScrollPane
代替LineBorder