我有3045的表格！组件(1015个标签,1015个文本字段,1015个组合框).所有这些都在JPanel和JScrollPane中的JPanel中.问题是滚动是“滞后”.我的PC上有4GB RAM,所以我不认为这是问题所在.怎么了？

在我的任务管理器中,应用程序使用~100mb.

我的代码：

final JScrollPane scrollPane_1 = new JScrollPane();

final JPanel panel = new JPanel();

panel.setLayout(null);

scrollPane_1.setViewportView(panel);

int y =0;

for(int i=0; i<1015;i++)

{

JLabel length = new JLabel();

length.setBounds(10, y, 350, 20);

length.setFont(new Font("Tahoma", Font.BOLD, 11));

length.setEnabled(false);

panel.add(length);

panel.revalidate();

JComboBox combo = new JComboBox();

combo.setModel(new DefaultComboBoxModel(new String[] {"=", "!="}));

combo.setBounds(10, y + 20, 70, 20);

panel.add(combo);

panel.revalidate();

JTextField text = new JTextField();

text.setBounds(10 + 80, y + 20, 200, 20);

panel.add(text);

panel.revalidate();

}

编辑：我做了很多测试,我意识到只有当我使用组合框时才存在延迟,如果我使用例如文本字段而不是组合框,滚动是正常的…

解决方法:

使用布局管理器时,您的代码对我来说似乎并不那么迟钝.请测试一下：

import java.awt.Dimension;

import java.awt.Font;

import java.awt.GridLayout;

import javax.swing.*;

public class Foo2 {

protected static final int PREF_W = 400;

protected static final int PREF_H = 400;

public static void main(String[] args) {

final JScrollPane scrollPane_1 = new JScrollPane() {

@Override

public Dimension getPreferredSize() {

return new Dimension(PREF_W, PREF_H);

}

};

final JPanel panel = new JPanel();

panel.setLayout(new GridLayout(0, 1));

scrollPane_1.setViewportView(panel);

for (int i = 0; i < 1015; i++) {

JPanel innerPanel = new JPanel();

innerPanel.setLayout(new BoxLayout(innerPanel, BoxLayout.LINE_AXIS));

JLabel length = new JLabel("foo");

length.setFont(new Font("Tahoma", Font.BOLD, 11));

length.setEnabled(false);

innerPanel.add(length);

innerPanel.add(Box.createHorizontalGlue());

JComboBox combo = new JComboBox();

combo.setPrototypeDisplayValue(" ");

combo.setModel(new DefaultComboBoxModel(new String[] { "=", "!=" }));

combo.setMaximumSize(combo.getPreferredSize());

innerPanel.add(combo);

JTextField text = new JTextField(10);

JPanel textWrapper = new JPanel();

textWrapper.add(text);

innerPanel.add(textWrapper);

panel.add(innerPanel);

}

JFrame frame = new JFrame();

frame.add(scrollPane_1);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.pack();

frame.setLocationRelativeTo(null);

frame.setVisible(true);

}

}

编辑

相反,使用JTable怎么样？

import java.awt.Dimension;

import java.awt.GridLayout;

import javax.swing.*;

import javax.swing.table.DefaultTableModel;

public class Foo3 {

protected static final int PREF_W = 400;

protected static final int PREF_H = 400;

public static void main(String[] args) {

final JScrollPane scrollPane_1 = new JScrollPane() {

@Override

public Dimension getPreferredSize() {

return new Dimension(PREF_W, PREF_H);

}

};

String[] columnNames = {"Foo", "Bar", "Baz"};

String[][] data = new String[1015][3];

for (int i = 0; i < data.length; i++) {

data[i] = new String[]{"foo", "==", ""};

}

DefaultTableModel model = new DefaultTableModel(data, columnNames){

@Override

public boolean isCellEditable(int row, int column) {

return (column != 0);

}

};

JTable table = new JTable(model);

table.getColumnModel().getColumn(1).setCellEditor(new DefaultCellEditor(

new JComboBox(new String[]{"==", "!="})));

final JPanel panel = new JPanel();

panel.setLayout(new GridLayout(0, 1));

scrollPane_1.setViewportView(table);

JFrame frame = new JFrame();

frame.add(scrollPane_1);

frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

frame.pack();

frame.setLocationRelativeTo(null);

frame.setVisible(true);

}

}

标签：java,performance,swing,jscrollpane

来源： https://codeday.me/bug/20190728/1567100.html