Java学习——用户界面的布局

使用布局管理器

　　FlowLayout管理器

　　面板的默认布局管理器是java.awt包中的FlowLayout类。使用FlowLayout时，像在页面中排列英文单词那样排组件：从左到右排列，当前行没有空间后进入下一行。

 import java.awt.*;
 import javax.swing.*;

 public class Crisis extends JFrame {
     JButton panicButton;
     JButton dontPanicButton;
     JButton blameButton;
     JButton mediaButton;
     JButton saveButton;

     public Crisis() {
         super("Crisis");
         setLookAndFeel();
         setSize(348, 128);
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 //        1.默认布局
         FlowLayout flo = new FlowLayout();
         setLayout(flo);
         panicButton = new JButton("Panic");
         dontPanicButton = new JButton("Don't Panic");
         blameButton = new JButton("Blame Others");
         mediaButton = new JButton("Notify the Media");
         saveButton  = new JButton("save yourself");
         add(panicButton);
         add(dontPanicButton);
         add(blameButton);
         add(mediaButton);
         add(saveButton);
         setVisible(true);
     }

     private void setLookAndFeel() {
         try {
             UIManager.setLookAndFeel(
                     "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
         } catch (Exception exc) {
             // ignore error
         }
     }

     public static void main(String[] arguments) {
         Crisis frame = new Crisis();
     }
 }

　　GridLayout管理器

　　GridLayout类位于java.awt包中，它将容器中所有的组件组织为指定的行数和列数。分配给每个组件的显示区域都相同。

　　当组件加入到容器中时，GridLayout将所有的组件放置到网格中的某个位置，而且组件是从左到右依次添加，当这一行满了之后，在从下一行的最左边开始添加。

 import java.awt.*;
 import javax.swing.*;

 public class Crisis extends JFrame {
     JButton panicButton;
     JButton dontPanicButton;
     JButton blameButton;
     JButton mediaButton;
     JButton saveButton;

     public Crisis() {
         super("Crisis");
         setLookAndFeel();
         setSize(348, 128);
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

 //        2.GridLayout布局
         GridLayout grid = new GridLayout(2, 3);
         setLayout(grid);
         panicButton = new JButton("Panic");
         dontPanicButton = new JButton("Don't Panic");
         blameButton = new JButton("Blame Others");
         mediaButton = new JButton("Notify the Media");
         saveButton  = new JButton("save yourself");
         add(panicButton);
         add(dontPanicButton);
         add(blameButton);
         add(mediaButton);
         add(saveButton);
         setVisible(true);
     }

     private void setLookAndFeel() {
         try {
             UIManager.setLookAndFeel(
                     "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
         } catch (Exception exc) {
             // ignore error
         }
     }

     public static void main(String[] arguments) {
         Crisis frame = new Crisis();
     }
 }

BorderLay管理器

　　BorderLayout类也位于java.awt包中，它将容器中的组件放置在特定的位置，该位置有5个方位：东、西、南、北、中。

BorderLayout管理器将组件放置到5个位置：其中4个位置由罗盘方向指定，另外一个由中心区域指定。当在该布局下添加组件时，add()方法会包含第2个参数，用于指示组件应该放置的位置。该参数应该是BorderLayout类的5个类变量之一：NORTH、SOUTH、EAST、WEST和CENTER。

　　与GridLayout类相同，BorderLayout也会将所有可用空间都分配给组件。在周围放置4个边界组件后，余下的空间都分配给中央的组件，因此它通常是最大的。

 import java.awt.*;
 import javax.swing.*;

 public class Crisis extends JFrame {
     JButton panicButton;
     JButton dontPanicButton;
     JButton blameButton;
     JButton mediaButton;
     JButton saveButton;

     public Crisis() {
         super("Crisis");
         setLookAndFeel();
         setSize(348, 128);
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         BorderLayout crisisLayout = new BorderLayout();
         setLayout(crisisLayout);

         panicButton = new JButton("Panic");
         dontPanicButton = new JButton("Don't Panic");
         blameButton = new JButton("Blame Others");
         mediaButton = new JButton("Notify the Media");
         saveButton  = new JButton("save yourself");
         add(panicButton, BorderLayout.NORTH);
         add(dontPanicButton, BorderLayout.SOUTH);
         add(blameButton, BorderLayout.EAST);
         add(mediaButton, BorderLayout.WEST);
         add(saveButton, BorderLayout.CENTER);
         setVisible(true);
     }

     private void setLookAndFeel() {
         try {
             UIManager.setLookAndFeel(
                     "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
         } catch (Exception exc) {
             // ignore error
         }
     }

     public static void main(String[] arguments) {
         Crisis frame = new Crisis();
     }
 }

BoxLayout管理器

　　BoxLayout类位于javax.swing包中，它可以将组件排列成一行或一列。

　　使用该布局时，先创建一个放置组件的面板，然后再创建一个布局管理器，它带有2个参数：

　　1.以框式布局组织的组件；

　　2.BoxLayout.Y_AXIS指定垂直排列，BoxLayout.X_AXIS指定水平排列；

 import java.awt.*;
 import javax.swing.*;

 public class Crisis extends JFrame {
     JButton panicButton;
     JButton dontPanicButton;
     JButton blameButton;
     JButton mediaButton;
     JButton saveButton;

     public Crisis() {
         super("Crisis");
         setLookAndFeel();
         setSize(348, 128);
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         JPanel pane = new JPanel();
         BoxLayout box = new BoxLayout(pane, BoxLayout.Y_AXIS);
         pane.setLayout(box);
         panicButton = new JButton("Panic");
         dontPanicButton = new JButton("Don't Panic");
         blameButton = new JButton("Blame Others");
         mediaButton = new JButton("Notify the Media");
         saveButton  = new JButton("save yourself");
         pane.add(panicButton);
         pane.add(dontPanicButton);
         pane.add(blameButton);
         pane.add(mediaButton);
         pane.add(saveButton);
         add(pane);

         setVisible(true);
     }

     private void setLookAndFeel() {
         try {
             UIManager.setLookAndFeel(
                     "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
         } catch (Exception exc) {
             // ignore error
         }
     }

     public static void main(String[] arguments) {
         Crisis frame = new Crisis();
     }
 }

使用Insets将组件隔开

　　Insets类位于java.awt包中，它有一个接受4个参数的构造函数：在容器上、下、左、右留出的空间。每个参数都以像素为单位，像素是定义框架大小时使用的度量单位。

     public Insets getInsets() {
         Insets squeeze = new Insets(60, 15, 10, 15);
         return squeeze;
     }

　布局测试

 import java.awt.*;
 import javax.swing.*;

 public class LottoMadness extends JFrame {
     // set up row1
     JPanel row1 = new JPanel();
     ButtonGroup option = new ButtonGroup();
     JCheckBox quickpick = new JCheckBox("Quick Pick", false);
     JCheckBox personal  = new JCheckBox("Personal", true);
     // set up row2
     JPanel row2 = new JPanel();
     JLabel numbersLabel = new JLabel("Your picks: ", JLabel.RIGHT);
     JTextField[] numbers = new JTextField[6];
     JLabel winnersLabel = new JLabel("Winners: ", JLabel.RIGHT);
     JTextField[] winners = new JTextField[6];
     // set up row3
     JPanel row3 = new JPanel();
     JButton stop = new JButton("Stop");
     JButton play = new JButton("play");
     JButton reset = new JButton("Reset");
     // set up row4
     JPanel row4 = new JPanel();
     JLabel got3Label = new JLabel("3 of 6: ", JLabel.RIGHT);
     JTextField got3 = new JTextField("0");
     JLabel got4Label = new JLabel("4 of 6: ", JLabel.RIGHT);
     JTextField got4 = new JTextField("0");
     JLabel got5Label = new JLabel("5 of 6: ", JLabel.RIGHT);
     JTextField got5 = new JTextField("0");
     JLabel got6Label = new JLabel("6 of 6: ", JLabel.RIGHT);
     JTextField got6 = new JTextField("0");
     JLabel drawingsLabel = new JLabel("Drawings", JLabel.RIGHT);
     JTextField drawings = new JTextField("0");
     JLabel yearsLabel = new JLabel("Years: ", JLabel.RIGHT);
     JTextField years = new JTextField();

     public LottoMadness() {
         super("Lotto Madness");

         setSize(550, 400);
         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
         GridLayout layout = new GridLayout(5, 1, 10, 10);
         setLayout(layout);

         FlowLayout layout1 = new FlowLayout(FlowLayout.CENTER, 10, 10);
         option.add(quickpick);
         option.add(personal);
         row1.setLayout(layout1);
         row1.add(quickpick);
         row1.add(personal);
         add(row1);

         GridLayout layout2 = new GridLayout(2, 7, 10, 10);
         row2.setLayout(layout2);
         row2.add(numbersLabel);
         for (int i = 0; i < 6; i++) {
             numbers[i] = new JTextField();
             row2.add(numbers[i]);
         }
         row2.add(winnersLabel);
         for (int i = 0; i < 6; i++) {
             winners[i] = new JTextField();
             winners[i].setEditable(false);
             row2.add(winners[i]);
         }
         add(row2);

         FlowLayout layout3 = new FlowLayout(FlowLayout.CENTER, 10, 10);
         row3.setLayout(layout3);
         stop.setEnabled(false);
         row3.add(stop);
         row3.add(play);
         row3.add(reset);
         add(row3);

         GridLayout layout4 = new GridLayout(2, 3, 20, 10);
         row4.setLayout(layout4);
         row4.add(got3Label);
         got3.setEditable(false);
         row4.add(got3);
         row4.add(got4Label);
         got4.setEditable(false);
         row4.add(got4);
         row4.add(got5Label);
         got5.setEditable(false);
         row4.add(got5);
         row4.add(got6Label);
         got6.setEditable(false);
         row4.add(got6);
         row4.add(drawingsLabel);
         drawings.setEditable(false);
         row4.add(drawings);
         row4.add(yearsLabel);
         years.setEditable(false);
         row4.add(years);
         add(row4);

         setVisible(true);
     }

     private static void setLookAndFeel() {
         try {
             UIManager.setLookAndFeel(
                     "com.sun.java.swing.plaf.nimbus.NimbusLookAndFeel");
         } catch (Exception exc) {
             // ignore error
         }
     }

     public static void main(String[] arguments) {
         LottoMadness.setLookAndFeel();
         LottoMadness frame = new LottoMadness();
     }
 }