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();
    }
}