Java this小技巧_javaz.size(this)-优快云博客

本文链接：https://blog.youkuaiyun.com/weizhaozhe/article/details/3941497

本文介绍了一个Java Swing程序，该程序允许用户通过按钮点击切换不同的用户界面外观和感觉（LookAndFeel）。程序利用了UIManager类来获取已安装的LookAndFeel，并为每种LookAndFeel创建一个按钮，点击后会更改整个应用程序的外观。

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当我们在写程序使，经常遇到相同的变量名无法区分，于是就使用：

this.a = a;

来区分，而当我们在使用嵌套类时，this就发生了混淆，我们不能得到外包类的this，所以就是用如下方式：

CLASSNAME.this

例子程序：

/**
*LookAndFeel.java
* Created on 9:01:54 AM Feb 27, 2009
*@author Quasar063501
*@version 0.1
*
*/
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JPanel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;

public class LookAndFeel extends JFrame {
private JPanel buttonPanel = null;

public void launchFrame() {
  this.setSize(200,300);
  buttonPanel = new JPanel();
  UIManager.LookAndFeelInfo[] infos = UIManager.getInstalledLookAndFeels();
  //new for
  for(UIManager.LookAndFeelInfo info : infos) {
   makeButton(info.getName(),info.getClassName());
  }

  this.add(buttonPanel);
  this.setVisible(true);
}

private void makeButton(String bName, final String lookName) {
  JButton b = new JButton(bName);
  buttonPanel.add(b);

  b.addActionListener(new ActionListener(){

   public void actionPerformed(ActionEvent e) {
    try {
     UIManager.setLookAndFeel(lookName);
    } catch (ClassNotFoundException e1) {
     e1.printStackTrace();
    } catch (InstantiationException e1) {
     e1.printStackTrace();
    } catch (IllegalAccessException e1) {
     e1.printStackTrace();
    } catch (UnsupportedLookAndFeelException e1) {
     e1.printStackTrace();
    }
    SwingUtilities.updateComponentTreeUI(LookAndFeel.this);
   }

  });
}

public static void main(String[] args) {
  new LookAndFeel().launchFrame();
}
}