布局管理简单认识

 

1.BorderLayout

把界面划分为东、南、西、北、中五个部分

若想添加更多的组件，可以建立多个panel,然后再panel中创建组件

默认把组件放在Center方向

import java.awt.Button;
import java.awt.Frame;
public class TestBoderLayout extends Frame{
public TestBoderLayout(){
add(new Button("East"),"East");
add(new Button("West"),"West");
add(new Button("Center"),"Center");
add(new Button("North"),"North");
add(new Button("South"),"South");
}
public static void main(String[] args) {
TestBoderLayout mainFrame = new TestBoderLayout();
mainFrame.setTitle("BorderLayout");
mainFrame.setSize(300,200);
mainFrame.setVisible(true);
}
}

2.FlowLayout

它是panel面板中默认的布局管理器

如果一行放不下，就会放到下一行放置

public class TestBoderLayout extends Frame{
public TestBoderLayout(){
setLayout(new FlowLayout());
add(new Button("East"));
add(new Button("West"));
add(new Button("Center"));
add(new Button("North"));
add(new Button("South"));
}
public static void main(String[] args) {
TestBoderLayout mainFrame = new TestBoderLayout();
mainFrame.setTitle("FlowLayout");
mainFrame.setSize(300,200);
mainFrame.setVisible(true);
}
}

 

3.GridLayout

将容器划分为若干行列的网格，在容器中添加组件时，它们会按从左到右，从上到下的顺序在网格中排列，需要指定在容器上划分的网格的行列数

4.CardLayout

可以将多个组件放在同一个容器区域内交替显示，相当于多张卡片摞在一起，只有最上面的一张可见

  import java.awt.*;
import java.awt.event.*;
public class TestCardLayout extends Frame{
Panel plWest = new Panel();
Panel plCenter = new Panel();
CardLayout cl = new CardLayout();
public TestCardLayout(){
plWest.setLayout(new GridLayout(3,1));
Button btnPrev = new Button("prev");
Button btnNext = new Button("next");
Button btnThree = new Button("three");
plWest.add(btnPrev);
plWest.add(btnNext);
plWest.add(btnThree);
plCenter.setLayout(cl);
plCenter.add(new Button("one"),"1");
plCenter.add(new Button("two"),"2");
plCenter.add(new Button("three"),"3");
plCenter.add(new Button("four"),"4");
plCenter.add(new Button("five"),"5");
class MyActionListener implements ActionListener{
public void actionPerformed(ActionEvent e){
if(e.getActionCommand().equals("prev")){
 cl.previous(plCenter);;
}
else if(e.getActionCommand().equals("next")){
cl.next(plCenter);
}
else{
cl.show(plCenter,"3");
}
}
}
add(plWest,"West");
add(plCenter);
MyActionListener ma = new MyActionListener();
btnPrev.addActionListener(ma);
btnNext.addActionListener(ma);
btnThree.addActionListener(ma);
}
public static void main(String[] args) {
TestCardLayout mainFrame = new TestCardLayout();
mainFrame.setTitle("CardLayout");
mainFrame.setSize(300,200);
mainFrame.setVisible(true);
}
}

5.GridBagLayout

布局管理器之王...

6.取消容器上布局管理器

Container.setLayout(null)取消布局管理器设置

Component.setBounds方法来设置每个组件的大小和位置

取消布局管理器，改变窗口大小，组件的大小不会适应窗口的改变

  import java.awt.*;
import java.awt.event.*;
public class TestCancelLayout extends Frame{
public TestCancelLayout(){
setLayout(null);
Button b1 = new Button("第一个按钮");
Button b2 = new Button("第二个按钮");
b1.setBounds(10,30,80,30);
b2.setBounds(60,70,100,20);
add(b1);
add(b2);
}
public static void main(String[] args) {
TestCancelLayout mainFrame = new TestCancelLayout();
mainFrame.setSize(300,200);
mainFrame.setVisible(true);
}
}