點擊一個按鈕

Question

我有一個JTextArea和一個JTextField，現在我想，如果我在JTextArea中點擊鏈接時轉到的JTextArea和 當我點擊JTextField的按鈕控制轉移到了JTextField，當開關的JTextField。我 沒有得到任何東西去做這樣的事情。 該程序只是基於點擊的JRadioButton來更改JTextField中的文本。

***This is the code:*** 



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


public class prg_32 extends JPanel implements ItemListener{ 

    JTextArea a1;  
    JButton t1,t2; 
    JRadioButton b1,b2,b3,b4; 
    JTextField fld1; 
    ButtonGroup grp; 
    GridBagConstraints gbc = new GridBagConstraints();  //GridBagConstraints object 

    public prg_32(){ 
     setLayout(new GridBagLayout()); 

     a1 = new JTextArea(3,10);  //TextArea 
     gbc.gridx = 0;    
     gbc.gridy = 0; 
     gbc.gridheight = 3; 
     gbc.fill = GridBagConstraints.VERTICAL; 
     add(a1,gbc);  //location of JTextArea 

     t1 = new JButton("TextArea"); 
     gbc.gridx = 1; 
     gbc.gridy = 0; 
     gbc.gridheight = 1; 
     add(t1,gbc);  //location of JButton 

     t2 = new JButton("TextField"); 
     gbc.gridx = 2; 
     gbc.gridy = 0; 
     gbc.gridheight = 1; 
     add(t2,gbc);  //location of JButton 

     b1 = new JRadioButton("Bold",false); 
     gbc.gridx = 1; 
     gbc.gridy = 1; 
     gbc.gridheight = 1; 
     add(b1,gbc); 

     b2 = new JRadioButton("Italic",false); 
     gbc.gridx = 2; 
     gbc.gridy = 1; 
     gbc.gridheight = 1; 
     add(b2,gbc); 

     b3 = new JRadioButton("Plain",false); 
     gbc.gridx = 1; 
     gbc.gridy = 2; 
     gbc.gridheight = 1; 
     add(b3,gbc); 

     b4 = new JRadioButton("Bold/Italic",true); 
     gbc.gridx = 2; 
     gbc.gridy = 2; 
     gbc.gridheight = 1; 
     add(b4,gbc); 

     grp = new ButtonGroup(); 
     grp.add(b1); 
     grp.add(b2); 
     grp.add(b3); 
     grp.add(b4); 

     fld1 = new JTextField("enter your name"); 
     gbc.gridx = 0; 
     gbc.gridy = 3; 
     gbc.gridwidth = 3; 
     gbc.fill = GridBagConstraints.HORIZONTAL; 
     add(fld1,gbc); 

     fld1.setFont(new Font("Serif",Font.BOLD + Font.ITALIC,14)); 

     b1.addItemListener(this);  //Event Handling 
     b2.addItemListener(this);  //Event Handling 
     b3.addItemListener(this);  //Event Handling 
     b4.addItemListener(this);  //Event Handling 
    } 

    public void itemStateChanged(ItemEvent e) { 
     Font font = null; 

     if(b1.isSelected()) 
      font = new Font("Serif",Font.BOLD,14); 
     else if(b2.isSelected()) 
      font = new Font("Serif",Font.ITALIC,14); 
     else if(b3.isSelected()) 
      font = new Font("Serif",Font.PLAIN,14); 
     else 
      font = new Font("Serif",Font.BOLD + Font.ITALIC,14); 

     fld1.setFont(font); 

    } 

    public static void main(String[] args){ 
     prg_32 px = new prg_32(); 
     JFrame jf = new JFrame(); 

     jf.setSize(500, 300); 
     jf.setVisible(true); 
     jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); 
     jf.add(px); 
    } 

} 

Answer 1

我建議實施一個ActionListener並使用它的方法Component.requestFocus()將焦點設置的文本字段。

t1 = new JButton("TextArea"); 
    t1.addActionListener(new ActionListener() { 

     @Override 
     public void actionPerformed(ActionEvent e) { 
      a1.requestFocus(); 

     } 
    }); 
    gbc.gridx = 1; 
    gbc.gridy = 0; 
    gbc.gridheight = 1; 
    add(t1,gbc);  //location of JButton 

    t2 = new JButton("TextField"); 
    t2.addActionListener(new ActionListener() { 

     @Override 
     public void actionPerformed(ActionEvent e) { 
      fld1.requestFocus(); 

     } 
    }); 
    gbc.gridx = 2; 
    gbc.gridy = 0; 
    gbc.gridheight = 1; 
    add(t2,gbc);