[javaSE] GUI（练习-列出指定目录内容）

import java.awt.Button;
import java.awt.FlowLayout;
import java.awt.Frame;
import java.awt.TextArea;
import java.awt.TextField;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.io.File;

public class FrameDemo {
    private Frame frame;
    private TextField tf;
    private TextArea ta;
    private Button button;

    public FrameDemo() {
        init();
    }

    /**
     * 初始化
     */
    public void init() {
        frame = new Frame("测试窗体");
        frame.setBounds(300, 200, 300, 400);
        frame.setLayout(new FlowLayout());

        tf = new TextField(20);
        button = new Button("转到");
        ta = new TextArea(30, 30);
        frame.add(button);
        frame.add(tf);
        frame.add(ta);
        frame.setVisible(true);

        addEventAction();
    }

    /**
     * 添加事件
     */
    public void addEventAction() {
        // 退出
        frame.addWindowListener(new WindowAdapter() {
            @Override
            public void windowClosing(WindowEvent e) {
                System.exit(0);
            }
        });
        // action事件
        button.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                String dirName = tf.getText();
                File file = new File(dirName);

                if (!file.isDirectory() || !file.exists()) {
                    ta.setText("目录不存在");
                    return;
                }

                String[] files = file.list();
                StringBuilder sb = new StringBuilder();
                for (String name : files) {
                    sb.append(name);
                    sb.append("\r\n");
                }
                ta.setText(sb.toString());
            }
        });
    }

    /**
     * @param args
     */
    public static void main(String[] args) {
        new FrameDemo();
    }

}