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📜  Java Swing-JTextArea

📅  最后修改于: 2020-09-29 10:00:59             🧑  作者: Mango

Java JTextArea

JTextArea类的对象是显示文本的多行区域。它允许编辑多行文本。它继承了JTextComponent类

JTextArea类声明

我们来看一下javax.swing.JTextArea类的声明。

public class JTextArea extends JTextComponent

常用的构造函数：

Constructor Description
JTextArea() Creates a text area that displays no text initially.
JTextArea(String s) Creates a text area that displays specified text initially.
JTextArea(int row, int column) Creates a text area with the specified number of rows and columns that displays no text initially.
JTextArea(String s, int row, int column) Creates a text area with the specified number of rows and columns that displays specified text.

常用方法：

Methods Description
void setRows(int rows) It is used to set specified number of rows.
void setColumns(int cols) It is used to set specified number of columns.
void setFont(Font f) It is used to set the specified font.
void insert(String s, int position) It is used to insert the specified text on the specified position.
void append(String s) It is used to append the given text to the end of the document.

Java JTextArea示例

import javax.swing.*;
public class TextAreaExample
{
 TextAreaExample(){
    JFrame f= new JFrame();
        JTextArea area=new JTextArea("Welcome to javatpoint");
    area.setBounds(10,30, 200,200);
    f.add(area);
    f.setSize(300,300);
    f.setLayout(null);
    f.setVisible(true);
 }
public static void main(String args[])
    {
   new TextAreaExample();
    }}

输出：

带有ActionListener的Java JTextArea示例

import javax.swing.*;
import java.awt.event.*;
public class TextAreaExample implements ActionListener{
JLabel l1,l2;
JTextArea area;
JButton b;
TextAreaExample() {
    JFrame f= new JFrame();
l1=new JLabel();
l1.setBounds(50,25,100,30);
l2=new JLabel();
l2.setBounds(160,25,100,30);
area=new JTextArea();
area.setBounds(20,75,250,200);
b=new JButton("Count Words");
b.setBounds(100,300,120,30);
b.addActionListener(this);
f.add(l1);f.add(l2);f.add(area);f.add(b);
f.setSize(450,450);
f.setLayout(null);
f.setVisible(true);
}
public void actionPerformed(ActionEvent e){
String text=area.getText();
String words[]=text.split("\\s");
l1.setText("Words: "+words.length);
l2.setText("Characters: "+text.length());
}
public static void main(String[] args) {
new TextAreaExample();
}
}

输出：