raspberry pi禁用java中的其他声音

Question

我用Java编写了一个程序，使用pi4j库在单击（物理）按钮时发出声音。这个程序可以工作，但现在它可以交替播放所有声音。我希望当你点击2，3，4或更多的按钮时，你只听到一个声音

这是我希望你能帮助的代码

public class ButtonSoundsProject{
public static void main(String args[]) throws InterruptedException {
    System.out.println("Toy has been started!");

    // create gpio controller
    final GpioController gpio = GpioFactory.getInstance();

    // provision gpio pin #02 as an input pin with its internal pull down resistor enabled
    GpioPinDigitalInput[] pins = {
        gpio.provisionDigitalInputPin(RaspiPin.GPIO_00, PinPullResistance.PULL_DOWN),
        gpio.provisionDigitalInputPin(RaspiPin.GPIO_01, PinPullResistance.PULL_DOWN),
        gpio.provisionDigitalInputPin(RaspiPin.GPIO_02, PinPullResistance.PULL_DOWN),
        gpio.provisionDigitalInputPin(RaspiPin.GPIO_03, PinPullResistance.PULL_DOWN),
        gpio.provisionDigitalInputPin(RaspiPin.GPIO_04, PinPullResistance.PULL_DOWN),
        gpio.provisionDigitalInputPin(RaspiPin.GPIO_05, PinPullResistance.PULL_DOWN),};

    final ArrayList<String> soundList = new ArrayList<String>();
    soundList.add("/home/pi/Sounds/Sound1.wav");
    soundList.add("/home/pi/Sounds/Sound2.wav");
    soundList.add("/home/pi/Sounds/Sound3.wav");
    soundList.add("/home/pi/Sounds/Sound4.wav");
    soundList.add("/home/pi/Sounds/Sound5.wav");
    soundList.add("/home/pi/Sounds/Sound6.wav");
    soundList.add("/home/pi/Sounds/Sound7.wav");
    soundList.add("/home/pi/Sounds/Sound8.wav");
    soundList.add("/home/pi/Sounds/Sound9.wav");
    soundList.add("/home/pi/Sounds/Sound10.wav");
    soundList.add("/home/pi/Sounds/Sound11.wav");
    soundList.add("/home/pi/Sounds/Sound12.wav");


    // create and register gpio pin listener
    GpioPinListenerDigital listener = new GpioPinListenerDigital() {
        @Override
        public void handleGpioPinDigitalStateChangeEvent(GpioPinDigitalStateChangeEvent event) {
            // display pin state on console

            final int randomNum = 0 + (int) (Math.random() * 12);
            System.out.println(randomNum);

            System.out.println(" --> GPIO PIN STATE CHANGE: " + event.getPin() + " = " + event.getState());
            InputStream in;
            try {
                System.out.println(soundList.get(randomNum).toString());
                String filepath = soundList.get(randomNum).toString();
                in = new FileInputStream(new File(filepath));
                AudioStream as = new AudioStream(in);
                AudioPlayer.player.start(as);

            } catch (Exception ex) {
                ex.printStackTrace();
            }
        }

    };

    gpio.addListener(listener, pins);


    for (;;) {
        Thread.sleep(500);
    }
}

}    

Answer 1

如评论中所述，我无法就AudioStream和AudioPlayer类向您提供建议，因为我的JDK中似乎没有这些类。因为我的方法是相似的，我会给你我所拥有的，希望你能从那里得到

基本上，解决方案是停止和/或“静音”该音频剪辑。这就是我如何使用javax.sound包实现它的方法：

private Clip currentAudioClip; // Keep a reference to the current clip being played

public void handleGpioPinDigitalStateChangeEvent(GpioPinDigitalStateChangeEvent event) {

    // Call this every time regardless.
    // If nothing is playing, this will do nothing.
    stopAudio();

    String filepath = soundList.get(randomNum)
    URL soundFileUrl = new File(filePath).toURI().toURL();

    AudioInputStream audioInputStream = AudioSystem.getAudioInputStream(soundFileUrl);

    Line.Info lineInfo = new Line.Info(Clip.class);
    Line line = AudioSystem.getLine(lineInfo);

    currentAudioClip = (Clip) line;
    currentAudioClip.open(audioInputStream);
    audioClip.start();

    // Alternative if you want to loop continuously. Comment out the `.start` line to use this.
    // audioClip.loop(Clip.LOOP_CONTINUOUSLY);
}

public void stopAudio(){
    if(audioClip != null){
        muteLine(); // A gotcha I discovered (see explanation below)
        audioClip.stop();

        // audioClip.loop(0); // if you chose to loop, use this instead of `.stop()`
        audioClip.flush();
        audioClip = null;
    }
}

public void muteLine(){
    BooleanControl muteControl = (BooleanControl) audioClip.getControl(BooleanControl.Type.MUTE);
    if(muteControl != null){
        muteControl.setValue(true); // True to mute the line, false to unmute
    }       
}

简而言之，每次触发pin状态更改事件时，前一个音频剪辑将停止，并播放新的音频剪辑。你不应该听到任何与此重叠的声音

还要注意，这是对我的原始代码的轻微修改，所以如果有任何问题，请告诉我

关于GOTCHA的注意事项

我在Raspberry PI Stackexchange上写了a question关于我遇到的一个奇怪问题。问题是，我发现我的音频剪辑不会停止播放命令。它将继续播放一段看似随意的时间。奇怪的是，我只是在树莓上测试应用时才注意到这一点；它在我本地的机器上运行得非常好（甚至在其他几台机器上）

我的问题可能与剪辑的“循环”有关；如果是这样的话，你只是想让剪辑按其长度播放，而不是进一步播放，你可能不会遇到这个问题，你可能可以省去我附带的“静音”代码。然而，如果你观察到同样的问题，至少你有一个解决方案

希望这有帮助，如果你有任何问题，请告诉我