JAVA筆記【20131223】

一、複選框

複選框（JCheckBox）自動的帶有標識標籤，複選框點擊選擇再點擊則取消，複選框是當前焦點的時候，也可以通過按空格鍵來進行選擇和取消選擇。

複選框可以通過調用setSelected()方法設置當前是選擇了還是沒選擇，可以通過isSelected()方法獲取當前是否已經選擇。

用戶選擇複選框時，會觸發一個動作事件。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class CheckBoxText01
{
	public static void main(String[] args)
	{
		CheckBoxFrame checkBox = new CheckBoxFrame();
		checkBox.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		checkBox.setVisible(true);
	}
}

class CheckBoxFrame extends JFrame
{
	public CheckBoxFrame()
	{
		setTitle("checkBox");
		setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
		textLabel=new JLabel("The quick brown fox jumps over the lazy dog");
		textLabel.setFont(new Font("serif",Font.PLAIN,FONT_SIZE));
		boxBold=new JCheckBox("Bold");
		boxItalic = new JCheckBox("Italic");
		
		JPanel centerPanel=new JPanel();
		centerPanel.add(textLabel);
		add(centerPanel,BorderLayout.CENTER);
		
		JPanel southPanel = new JPanel();
		southPanel.add(boxBold);
		southPanel.add(boxItalic);
		add(southPanel,BorderLayout.SOUTH);
		
		ActionListener checkBoxListener = new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				int mode=0;
				if(boxBold.isSelected())
				{
					mode += Font.BOLD;
					textLabel.setFont(new Font("serif",mode,FONT_SIZE));
				}
				if(boxItalic.isSelected())
				{
					mode += Font.ITALIC;
					textLabel.setFont(new Font("serif",mode,FONT_SIZE));
				}
				if((boxBold.isSelected()||boxItalic.isSelected())==false)
				{
					textLabel.setFont(new Font("serif",Font.PLAIN,FONT_SIZE));
				}
			}
		};
		boxBold.addActionListener(checkBoxListener);
		boxItalic.addActionListener(checkBoxListener);
	}
	private JLabel textLabel;
	private JCheckBox boxBold;
	private JCheckBox boxItalic;
	private static final int DEFAULT_WIDTH=400;
	private static final int DEFAULT_HEIGHT=100;
	private static final int FONT_SIZE=12;
}

二、單選框和邊界

單選按鈕也就是一組按鈕同一時間只能按下一個的按鈕。Swing組件中爲單選按鈕組構造了一個ButtonGroup類，把單選按鈕JRadioButton添加到按鈕組ButtonGroup即可。

ButtonGroup butGroup = new ButtonGroup();
JRadioButton jradio1 = new JRadioButton("small",false);
JRadioButton jradio2 = new JRadioButton("medium",true);
JRadioButton jradio3 = new JRadioButton("large",false);
butGroup.add(jradio1);
butGroup.add(jradio2);
butGroup.add(jradio3);

單選按鈕JRadioButton的構造方法中第二個參數用於指定該按鈕初始狀態是否已經選擇。按鈕組只是管理按鈕的行爲，對於單選按鈕仍然需添加到容器中佈局。

對於邊界其實就是一個組件的邊界部分。可以在任何繼承了JComponent的組件上應用邊界。最常用的是在面板周圍設置邊界。

工廠類BorderFactory中的靜態方法可以創建邊界風格，實現了Border接口的類也可以作爲邊界，有些SoftBevelBorder類LineBorder類等。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
import javax.swing.border.*;
public class RadioButtonTest01
{
	public static void main(String[] args)
	{
		RadioButtonFrame checkBox = new RadioButtonFrame();
		checkBox.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		checkBox.setVisible(true);
	}
}

class RadioButtonFrame extends JFrame
{
	public RadioButtonFrame()
	{
		setTitle("RadioButton");
		setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
		textLabel=new JLabel("The quick brown fox jumps over the lazy dog");
		textLabel.setFont(new Font("serif",Font.PLAIN,DEFAULT_FONT_SIZE));
		
		JPanel centerPanel=new JPanel();
		centerPanel.add(textLabel);
		add(centerPanel,BorderLayout.NORTH);
		
		butGroupPanel=new JPanel();
		butGroup = new ButtonGroup();

		//SoftBevelBorder beve = new SoftBevelBorder(SoftBevelBorder.RAISED);
		LineBorder line = new LineBorder(Color.BLUE,10,true);
		butGroupPanel.setBorder(BorderFactory.createTitledBorder(line,"字體大小調整"));
		//butGroupPanel.setBorder(line);
		
		addRadioButton("small",SMALL_FONT_SIZE);
		addRadioButton("medium",MEDIUM_FONT_SIZE);
		addRadioButton("large",LARGE_FONT_SIZE);
		addRadioButton("extra large",EXTRA_FONT_SIZE);
		
		add(butGroupPanel,BorderLayout.CENTER);
	}
	
	public void addRadioButton(String name,final int size)
	{
		JRadioButton jradio = new JRadioButton(name,false);
		ActionListener actListener = new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				textLabel.setFont(new Font("Serif",Font.PLAIN,size));
			}
		};
		jradio.addActionListener(actListener);
		butGroup.add(jradio);
		butGroupPanel.add(jradio);
	}
	
	private JLabel textLabel;
	private JPanel butGroupPanel;
	private ButtonGroup butGroup;
	private static final int DEFAULT_WIDTH=600;
	private static final int DEFAULT_HEIGHT=150;
	private static final int DEFAULT_FONT_SIZE=12;
	private static final int SMALL_FONT_SIZE=6;
	private static final int MEDIUM_FONT_SIZE=12;
	private static final int LARGE_FONT_SIZE=18;
	private static final int EXTRA_FONT_SIZE=36;
}

運行效果：

三、組合框

組合框（JComboBox）類似下拉菜單一樣，可以選擇預先設定的內容。也可以通過setEditable方法設置組合框是否可編輯。

通過調用addItem方法可以將一個選項添加到選項列表中，removeItem方法可以刪除一個選項。getSelectedItem方法用於獲取當前選擇的選項。

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class CheckBoxText01
{
	public static void main(String[] args)
	{
		CheckBoxFrame checkBox = new CheckBoxFrame();
		checkBox.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
		checkBox.setVisible(true);
	}
}

class CheckBoxFrame extends JFrame
{
	public CheckBoxFrame()
	{
		setTitle("checkBox");
		setSize(DEFAULT_WIDTH,DEFAULT_HEIGHT);
		textLabel=new JLabel("The quick brown fox jumps over the lazy dog");
		textLabel.setFont(new Font("serif",Font.PLAIN,FONT_SIZE));
		boxBold=new JCheckBox("Bold");
		boxItalic = new JCheckBox("Italic");
		
		JPanel centerPanel=new JPanel();
		centerPanel.add(textLabel);
		add(centerPanel,BorderLayout.CENTER);
		
		JPanel southPanel = new JPanel();
		
		fontCombo = new JComboBox();
		fontCombo.setEditable(false);
		fontCombo.addItem("Serif");
		fontCombo.addItem("SansSerif");
		fontCombo.addItem("Monospaced");
		fontCombo.addItem("Dialog");
		fontCombo.addItem("DialogInput");
		
		southPanel.add(fontCombo);
		southPanel.add(boxBold);
		southPanel.add(boxItalic);
		add(southPanel,BorderLayout.SOUTH);
		
		ActionListener checkBoxListener = new ActionListener()
		{
			public void actionPerformed(ActionEvent e)
			{
				int mode=0;
				if(boxBold.isSelected())
				{
					mode += Font.BOLD;
					textLabel.setFont(new Font("serif",mode,FONT_SIZE));
				}
				if(boxItalic.isSelected())
				{
					mode += Font.ITALIC;
					textLabel.setFont(new Font("serif",mode,FONT_SIZE));
				}
				if((boxBold.isSelected()||boxItalic.isSelected())==false)
				{
					textLabel.setFont(new Font("serif",Font.PLAIN,FONT_SIZE));
				}
			}
		};
		boxBold.addActionListener(checkBoxListener);
		boxItalic.addActionListener(checkBoxListener);
		
		fontCombo.addActionListener(
			new ActionListener()
			{
				public void actionPerformed(ActionEvent e)
				{
					String style=(String)fontCombo.getSelectedItem();
					if(boxBold.isSelected())
					{
						textLabel.setFont(new Font(style,Font.BOLD,FONT_SIZE));
					}
					if(boxItalic.isSelected())
					{
						textLabel.setFont(new Font(style,Font.ITALIC,FONT_SIZE));
					}
					if((boxBold.isSelected()&&boxItalic.isSelected())==true)
					{
						textLabel.setFont(new Font(style,Font.ITALIC+Font.BOLD,FONT_SIZE));
					}
					if((boxBold.isSelected()||boxItalic.isSelected())==false)
					{
						textLabel.setFont(new Font(style,Font.PLAIN,FONT_SIZE));
					}
			  }
			}
		);
	}
	
	private JComboBox fontCombo;
	private JLabel textLabel;
	private JCheckBox boxBold;
	private JCheckBox boxItalic;
	private static final int DEFAULT_WIDTH=400;
	private static final int DEFAULT_HEIGHT=100;
	private static final int FONT_SIZE=12;
}

運行結果：