Question

注：A.java使用了未经检查或不安全的操作。 注：有关详细信息，请使用-Xlint:unchecked重新编译。

import java.awt.*;
import java.net.*;
import java.awt.event.*;
import java.io.*;
import java.applet.*;
import javax.swing.*;
public class AudioClipDialog extends JDialog implements Runnable,
ItemListener,ActionListener{
Thread thread;
JComboBox choiceMusic;
AudioClip clip;
JButton buttonPlay,
buttonLoop,
buttonStop;
String str;
AudioClipDialog(){
thread = new Thread(this);
choiceMusic = new JComboBox();
choiceMusic.addItem("选择音频文件");
choiceMusic.addItem("musicOne.wav");
choiceMusic.addItem("musicTwo.wav");
choiceMusic.addItem("musicThree.wav");
choiceMusic.addItemListener(this);
buttonPlay = new JButton("播放");
buttonLoop = new JButton("循环");
buttonStop = new JButton("停止");
buttonPlay.addActionListener(this);
buttonStop.addActionListener(this);
buttonLoop.addActionListener(this);
setLayout(new FlowLayout());
add(choiceMusic);
add(buttonPlay);
add(buttonLoop);
add(buttonStop);
setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
setSize(350,120);
}
public void itemStateChanged(ItemEvent e){
str = choiceMusic.getSelectedItem().toString();
if(!(thread.isAlive())){
thread = new Thread(this);
}
try{
thread.start();
}
catch(Exception ee){ };
}
public void run(){
try{ File file = new File(str);
URI uri = file.toURI();
URL url = uri.toURL();
clip = Applet.newAudioClip(url);
}
catch(Exception e){ }
}
public void actionPerformed(ActionEvent e){
if(e.getSource() == buttonPlay)
clip.play();
else if(e.getSource() == buttonLoop)
clip.loop();
else if(e.getSource() == buttonStop)
clip.stop();
}
}

Answer 1

您好，提问者：
JComboBox<String> choiceMusic; //这里使用了泛型，所以...
choiceMusic = new JComboBox<String>();这个地方也要改。
就好比：List list = new ArrayList(); //这也需要泛型，不然也会提示。
另外：这种提示只是一个警告，可以直接运行，不用理会没事。