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[英]Why is this method and for loop executing more times than I want it to?
[英]java - for loop is executing more times than it should - metronome program
我正在創建一個節拍器程序,並且for循環比應執行的執行+1次。
public class Tempo {
String file;
int bpm;
public Tempo(int bpm, String file){
this.bpm=bpm;
this.file=file;
}
public void tempoPlay () throws InterruptedException{
new Play(file).start();
Thread.sleep(60000/bpm);
}
public static void main(String[] args) throws InterruptedException {
Tempo t = new Tempo(120, "C:\\Users\\Korisnik\\Desktop\\dome3.wav");
for(int i=0;i<20;i++){
t.tempoPlay();
}
}
}
第一個拍子緊隨其后,第二個拍子緊隨其后。 我已經計算出它可以播放21拍,但應該可以播放20拍。這是Play課:
import java.io.File;
import java.io.IOException;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
import javax.sound.sampled.DataLine;
import javax.sound.sampled.FloatControl;
import javax.sound.sampled.LineUnavailableException;
import javax.sound.sampled.SourceDataLine;
import javax.sound.sampled.UnsupportedAudioFileException;
class Play extends Thread {
private String filename;
private Position curPosition;
private final int EXTERNAL_BUFFER_SIZE = 524288; // 128Kb
enum Position {
LEFT, RIGHT, NORMAL
};
public Play(String wavfile) {
filename = wavfile;
curPosition = Position.NORMAL;
}
public Play(String wavfile, Position p) {
filename = wavfile;
curPosition = p;
}
@Override
public void run() {
File soundFile = new File(filename);
if (!soundFile.exists()) {
System.err.println("Wave file not found: " + filename);
return;
}
AudioInputStream audioInputStream = null;
try {
audioInputStream = AudioSystem.getAudioInputStream(soundFile);
} catch (UnsupportedAudioFileException e1) {
e1.printStackTrace();
return;
} catch (IOException e1) {
e1.printStackTrace();
return;
}
AudioFormat format = audioInputStream.getFormat();
SourceDataLine auline = null;
DataLine.Info info = new DataLine.Info(SourceDataLine.class, format);
try {
auline = (SourceDataLine) AudioSystem.getLine(info);
auline.open(format);
} catch (LineUnavailableException e) {
e.printStackTrace();
return;
} catch (Exception e) {
e.printStackTrace();
return;
}
if (auline.isControlSupported(FloatControl.Type.PAN)) {
FloatControl pan = (FloatControl) auline
.getControl(FloatControl.Type.PAN);
if (curPosition == Position.RIGHT) {
pan.setValue(1.0f);
} else if (curPosition == Position.LEFT) {
pan.setValue(-1.0f);
}
}
auline.start();
int nBytesRead = 0;
byte[] abData = new byte[EXTERNAL_BUFFER_SIZE];
try {
while (nBytesRead != -1) {
nBytesRead = audioInputStream.read(abData, 0, abData.length);
if (nBytesRead >= 0) {
auline.write(abData, 0, nBytesRead);
}
}
} catch (IOException e) {
e.printStackTrace();
return;
} finally {
auline.drain();
auline.close();
}
}
}
在黑暗中拍攝:將文件完全讀入內存以進行測試可能是值得的。 可能發生的猜測是讀取文件的I / O干擾了播放的時間。
您也許可以擺脫這種情況進行測試。
Tempo t = new Tempo(120, "C:\\Users\\Korisnik\\Desktop\\dome3.wav");
t.tempoPlay() // ignore this
Thread.sleep(10);
for(int i=0;i<20;i++){
t.tempoPlay();
}
或更妙的是,讓Tempo在播放聲音之前將讀入緩存。
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