java基础知识13-javaUI2

13-12-23 来源：[db:作者]

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java的Swing库采用Beans的方式允许我们更加方便的创建界面。

1：进度条

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.border.*;
public class Progress extends JPanel {
	JProgressBar pb = new JProgressBar();			//进度条
	JSlider sb = new JSlider(JSlider.HORIZONTAL, 0, 100, 60);//滑动条
	public Progress() {
		setLayout(new GridLayout(2,1));
		add(pb);
		sb.setValue(0);
		sb.setPaintTicks(true);
		sb.setMajorTickSpacing(20); //设置滑动条的主间隔个数
		sb.setMinorTickSpacing(5);  //每个间隔细分为5个间隔
		sb.setBorder(new TitledBorder("Slide Me"));
		pb.setModel(sb.getModel()); // Share model
		add(sb);
	}
	public static void main(String args[]) {
		JFrame jf = new JFrame();
		Progress pro = new Progress();
		jf.add(pro);
		jf.setSize(200,300);
		jf.setVisible(true);
	}
} ///:~

结果如下所示：

2：ButtonGroup以及动态映射

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;
import java.lang.reflect.*;
public class ButtonGroups extends JPanel {
	static String[] ids = { 
		"June", "Ward", "Beaver","Wally", "Eddie", "Lumpy",
	};
	static JPanel makeBPanel(Class bClass, String[] ids) {
		ButtonGroup bg = new ButtonGroup();
		JPanel jp = new JPanel();
		String title = bClass.getName();
		title = title.substring( title.lastIndexOf('.') + 1);
		jp.setBorder(new TitledBorder(title));
		for(int i = 0; i < ids.length; i++) {
			AbstractButton ab = new JButton("failed");
			try {
				//动态获得一个有一个String参数的构造函数
				Constructor ctor = bClass.getConstructor(new Class[] { String.class });
				//创造一个Object
				ab = (AbstractButton)ctor.newInstance(new Object[]{ids[i]});
			} catch(Exception ex) {
				System.out.println("can't create " + bClass);
			}
			bg.add(ab);//按钮组添加按钮
			jp.add(ab);
		}
		return jp;
	}
	public ButtonGroups() {
		add(makeBPanel(JButton.class, ids));
		add(makeBPanel(JToggleButton.class, ids));
		add(makeBPanel(JCheckBox.class, ids));
		add(makeBPanel(JRadioButton.class, ids));
	}
	public static void main(String args[]) {
		JFrame jf = new JFrame();
		ButtonGroups btg = new ButtonGroups();
		jf.add(btg);
		jf.setSize(500,300);
		jf.setVisible(true);
	}
} ///:~

结果如下所示：

这个程序的特点就是通过reflect来实现添加不同类型的按钮组，AbstractButton 是所有不同类型的button的父类，所以可以通过它来操作子类的重定义函数。通过Constructor ctor = bClass.getConstructor(new Class[] { String.class });来获得有一个参数是String类型的构造函数，通过ab = (AbstractButton)ctor.newInstance(new Object[]{ids[i]});来创建一个button的对象。
ButtonGroup的作用就是一个button组中有一个被选中其他button就处于落选状态。

3：按钮图标

static Icon face = new Icon（"face0.jpg"）;//建立图标
JButton jb = new JButton（"bt",face）;	   //建立带有图标的按钮
jb.setIcon(face);//设置图标
jb.setRolloverIcon(faces[1]);//设置滚动时的按钮图标
jb.setPressedIcon(faces[2]); //设置按下时的按钮图标
jb.setDisabledIcon(faces[4]);//设置禁用时的按钮图标

结果如下所示：

4:弹出菜单
弹出菜单也很简单，包括菜单的创建，菜单命令的响应，如下所示：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class Popup extends JPanel {
	JPopupMenu popup = new JPopupMenu();
	JTextField t = new JTextField(10);
	public Popup() {
		add(t);
		ActionListener al = new ActionListener() {
			public void actionPerformed(ActionEvent e){
				t.setText( ((JMenuItem)e.getSource()).getText());
			}
		};
		JMenuItem m = new JMenuItem("Hither");
		m.addActionListener(al);
		popup.add(m);
		
		m = new JMenuItem("Yon");
		m.addActionListener(al);
		popup.add(m);
		
		m = new JMenuItem("Afar");
		m.addActionListener(al);
		popup.add(m);
		popup.addSeparator();
		
		m = new JMenuItem("Stay Here");
		m.addActionListener(al);
		popup.add(m);
		
		PopupListener pl= new PopupListener();
		addMouseListener(pl);
		t.addMouseListener(pl);//这样即便鼠标点击label，也会弹出菜单
	}
	class PopupListener extends MouseAdapter {
		
		public void mousePressed(MouseEvent e) {
			maybeShowPopup(e);
		}
		
		public void mouseReleased(MouseEvent e) {
			maybeShowPopup(e);
		}
		
		private void maybeShowPopup(MouseEvent e) {
			//判断鼠标事件是否为弹出菜单的触发事件
			if(e.isPopupTrigger()) {
				popup.show(e.getComponent(), e.getX(), e.getY());
			}
		}
	}
	public static void main(String args[]) {
		JFrame jf = new JFrame();
		Popup pm = new Popup();
		jf.add(pm);
		jf.setSize(500,500);
		jf.setVisible(true);
	}
} ///:~

结果如下所示：

通过鼠标监听器来监听弹出菜单事件，e.isPopupTrigger()来判断是否是弹出菜单的触发事件；popup.show(e.getComponent(), e.getX(), e.getY());在点击鼠标的位置显示弹出菜单；

5:树形控件

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.tree.*;
// Takes an array of Strings and makes the first
// element a node and the rest leaves:
class Branch {
	DefaultMutableTreeNode r;
	public Branch(String[] data) {
		r = new DefaultMutableTreeNode(data[0]);
		for(int i = 1; i < data.length; i++)
			r.add(new DefaultMutableTreeNode(data[i]));
	}
	public DefaultMutableTreeNode node() { 
		return r; 
	}
} 
public class Trees extends JPanel {
	String[][] data = {
			{ "Colors", "Red", "Blue", "Green" },
			{ "Flavors", "Tart", "Sweet", "Bland" },
			{ "Length", "Short", "Medium", "Long" },
			{ "Volume", "High", "Medium", "Low" },
			{ "Temperature", "High", "Medium", "Low" },
			{ "Intensity", "High", "Medium", "Low" },
		};
	static int i = 0;
	DefaultMutableTreeNode root, child, chosen;
	JTree tree;
	DefaultTreeModel model;
	public Trees() {
		setLayout(new BorderLayout());
		root = new DefaultMutableTreeNode("root");//建立树的根节点
		tree = new JTree(root);//建立一棵树
		// Add it and make it take care of scrolling:
		add(new JScrollPane(tree), BorderLayout.CENTER);
		// Capture the tree's model:
		model =(DefaultTreeModel)tree.getModel();
		JButton test = new JButton("Press me");
		test.addActionListener(new ActionListener() {
			public void actionPerformed(ActionEvent e){
				if(i < data.length) 
				{
					//通过Branch建立子节点的所有节点
					child = new Branch(data[i++]).node();
					// What's the last one you clicked?
					chosen = (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();
					if(chosen == null)
						chosen = root;
					// The model will create the appropriate event. In 
					// response, the tree will update itself:
					model.insertNodeInto(child, chosen, 0);
					// This puts the new node on the currently chosen node.
				}
			}
		});
		// Change the button's colors:
		test.setBackground(Color.blue);
		test.setForeground(Color.white);
		JPanel p = new JPanel();
		p.add(test);
		add(p, BorderLayout.SOUTH);
	}
	public static void main(String args[]) {
		JFrame jf = new JFrame();
		Trees nt = new Trees();
		jf.add(nt);
		jf.setSize(1000,1000);
		jf.setVisible(true);
	}
} ///:~

结果如下所示：

程序中通过Branch来建立一个分支，这个分支是两层的，包含一个根节点以及几个叶子节点；
通过按钮PressMe来负责树形控件中节点的插入，
chosen = (DefaultMutableTreeNode)tree.getLastSelectedPathComponent();这句话获取最后选择的节点，插入会在此节点下插入；
model.insertNodeInto(child, chosen, 0);这句话表示插入分支child，插入位置是chosen，0表示插在它下面的第一个位置

6：表格的创建
java中表格的创建还是比较方便的，我们只需要实现interface TableModel中的三个主要的函数即可，所以我们要用到抽象类
AbstracttableModel,这个类实现了tableModel 中的大部分函数，但是三个函数
public int getRowCount();
public int getColumnCount();
public Object getValueAt(int row, int column);
需要我们另外独自去实现。下面的程序很好的说明了这一点：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.event.*;
// T he TableModel controls all the data:
class DataModel extends AbstractTableModel {
	Object[][] data = {
			{"one", "two", "three", "four"},
			{"five", "six", "seven", "eight"},
			{"nine", "ten", "eleven", "twelve"},
	};
	// Prints data when table changes:
	class TML implements TableModelListener {
		public void tableChanged(TableModelEvent e) {
			for(int i = 0; i < data.length; i++) {
				for(int j = 0; j < data[0].length; j++)
					System.out.print(data[i][j] + " ");
				System.out.println();
			}
		}
	}
	DataModel() {
		addTableModelListener(new TML());
	} 
	//必须完成interface TableModel的函数
	public int getColumnCount() { 
		return data[0].length; 
	}
	//必须完成interface TableModel的函数
	public int getRowCount() { 
		return data.length;
	}
	//必须完成interface TableModel的函数
	public Object getValueAt(int row, int col) { 
		return data[row][col]; 
	}
	public void setValueAt(Object val, int row, int col) {
		data[row][col] = val;
		// Indicate the change has happened:
		fireTableDataChanged();
	}
	public boolean isCellEditable(int row, int col) { 
		return true; 
	}
}; 
public class Table extends JPanel {
	public Table() {
		setLayout(new BorderLayout());
		JTable table = new JTable(new DataModel());
		JScrollPane scrollpane = JTable.createScrollPaneForTable(table);
		add(scrollpane, BorderLayout.CENTER);
	}
	public static void main(String args[]) {
		JFrame jf = new JFrame();
		Table ta = new Table();
		jf.add(ta);
		jf.setSize(300,300);
		jf.setVisible(true);
	}
}

结果如下所示：

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