java - JTextArea 中的滚动条

Question

我想在 textarea 中创建一个滚动条，但是如果我将 JPanel Layout 设置为 null，滚动条将不会显示!

我试过了

JScrollPane scrollbar1 = 
  new JScrollPane(
    ta1,JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED,
    JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);

但由于布局为空而无法正常工作。

这是我当前的代码:

import javax.swing.*;

import java.awt.*;
public class app extends JFrame {

    public static void main(String[] args)
    {
        new app();
    }

    public app()
    {
        this.setSize(400,400);
        this.setLocation(0,0);
        this.setResizable(false);
        this.setTitle("Application");           
        JPanel painel = new JPanel(null);           
        // Creating the Input
        JTextField tf1 = new JTextField("Some random text", 15);            
        tf1.setBounds(5,5,this.getWidth()-120,20);
        tf1.setColumns(10);
        tf1.setText("Omg");         
        painel.add(tf1);            
        // Creating the button          
        JButton button1 = new JButton("Send");          
        button1.setBounds(290, 5, 100, 19);         
        painel.add(button1);            
        // Creating the TextArea            
        JTextArea ta1 = new JTextArea(15, 20);
        JScrollPane scr = new JScrollPane();
        ta1.setBounds(5, 35, 385, 330);
        ta1.setLineWrap(true);
        ta1.setWrapStyleWord(true);         
        painel.add(ta1);
        this.add(painel);
        this.setVisible(true);
    }
}

我想让它正常工作。如果有人可以帮助我，请在下面发表评论!

Answer 1

我已经纠正了所有问题，以下是工作代码。请阅读有关更改的评论。

import javax.swing.*;

import java.awt.*;

public class app extends JFrame {

    public static void main(String[] args) {
        new app();
    }

    public app() {
        this.setSize(400, 400);
        this.setLocation(0, 0);
        this.setResizable(false);
        this.setTitle("Application");
        JPanel painel = new JPanel(null);
        // Creating the Input
        JTextField tf1 = new JTextField("Some random text", 15);
        tf1.setBounds(5, 5, this.getWidth() - 120, 20);
        tf1.setColumns(10);
        tf1.setText("Omg");

        // resultsTA,JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);
        painel.add(tf1);
        // Creating the button
        JButton button1 = new JButton("Send");
        button1.setBounds(290, 5, 100, 19);
        painel.add(button1);
        // Creating the TextArea
        JTextArea ta1 = new JTextArea(15, 20);
        JScrollPane scr = new JScrollPane(ta1,
                JScrollPane.VERTICAL_SCROLLBAR_ALWAYS,
                JScrollPane.HORIZONTAL_SCROLLBAR_ALWAYS);// Add your text area to scroll pane 
        ta1.setBounds(5, 35, 385, 330);
        ta1.setLineWrap(true);
        ta1.setWrapStyleWord(true);
        scr.setBounds(20, 30, 100, 40);// You have to set bounds for all the controls and containers incas eof null layout
        painel.add(scr);// Add you scroll pane to container
        this.add(painel);
        this.setVisible(true);
    }
}

编辑。请阅读 oracle 的 Java 教程。并开始使用适当的布局管理器......希望对你有帮助