我正在尝试使用Android Sensor TYPE_PROXIMITY控制声音播放速率。我已经完成编码，一切看起来都不错，但当我尝试在我的Android手机上运行我的代码时显示错误：
10-04 00:16:23.711 2024-2024 /？ E / AndroidRuntime：致命异常：主要 处理：com.example.leonzhang.clapapp，PID：2024 java.lang.RuntimeException：无法启动活动 ComponentInfo {com.example.leonzhang.clapapp / com.example.leonzhang.clapapp.MainActivity}： java.lang.NullPointerException：尝试调用虚方法＆＃39; void com.example.leonzhang.clapapp.SoundControl.addSound（INT， java.lang.String中）＆＃39;在null对象引用上 在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2416） 在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2476） 在android.app.ActivityThread.access $ 900（ActivityThread.java:150） 在android.app.ActivityThread $ H.handleMessage（ActivityThread.java:1344） 在android.os.Handler.dispatchMessage（Handler.java:102） 在android.os.Looper.loop（Looper.java:148） 在android.app.ActivityThread.main（ActivityThread.java:5417） at java.lang.reflect.Method.invoke（Native Method） 在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:764） 在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:626） 引起：java.lang.NullPointerException：尝试调用虚方法＆＃39; void com.example.leonzhang.clapapp.SoundControl.addSound（INT， java.lang.String中）＆＃39;在null对象引用上 在com.example.leonzhang.clapapp.MainActivity.onCreate（MainActivity.java:36） 在android.app.Activity.performCreate（Activity.java:6285） 在android.app.Instrumentation.callActivityOnCreate（Instrumentation.java:1108） 在android.app.ActivityThread.performLaunchActivity（ActivityThread.java:2369） 在android.app.ActivityThread.handleLaunchActivity（ActivityThread.java:2476）
at android.app.ActivityThread.access$900(ActivityThread.java:150) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1344) at android.os.Handler.dispatchMessage(Handler.java:102) at android.os.Looper.loop(Looper.java:148) at android.app.ActivityThread.main(ActivityThread.java:5417) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:764) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
我不知道如何为此错误修改我的代码。请给我一些帮助。非常感谢你
更新代码：
Mainactivity.java
public class MainActivity extends Activity implements SensorEventListener,View.OnClickListener {
private static final float SHAKE_THRESHOLD = 50;
private static final String TAG = "ActivityTest";
private SensorManager manager;
private SoundControl sm;
private long curTime, lastUpdate;
private float last_x, last_y, last_z;
private float x,y,z;
private boolean isPlaying;
private int count = -2;
private float force;
private int audioCount = 0;
private float audioForce;
private Button btn;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btn = (Button) this.findViewById(R.id.button);
btn.setOnClickListener(this);
manager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
sm = new SoundControl(this);
sm.addSound(1, "clapping.ogg");
}
@Override
public void onSensorChanged(SensorEvent event) {
curTime = System.currentTimeMillis();
if ((curTime - lastUpdate) > 100) {
count ++ ;
if (count < 0) {
return;
}
if (count == 0) {
if (!isPlaying) {
Log.i(TAG, "sm.play(1, 0, 1.0f);");
sm.play(1, 0, 1.0f);
}
last_x = event.values[SensorManager.DATA_X];
last_y = event.values[SensorManager.DATA_Y];
last_z = event.values[SensorManager.DATA_Z];
return;
}
lastUpdate = curTime;
x = event.values[SensorManager.DATA_X];
y = event.values[SensorManager.DATA_Y];
z = event.values[SensorManager.DATA_Z];
curTime = System.currentTimeMillis();
float deltaForce = Math.abs(x + y + z - last_x - last_y - last_z);
force = force + deltaForce;
updateAudioRate(deltaForce);
if (count >= SHAKE_THRESHOLD) {
Log.i(TAG, "unSensorListener");
// onShakeCallBack(force / count); get the score
unSensorListener();
if (isPlaying) {
sm.stop();
isPlaying = false;
}
count = - 2;
force = 0;
return;
}
last_x = x;
last_y = y;
last_z = z;
}
}
@Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
private void updateAudioRate(float force) {
float rate=0;
float prvAudioRate = 1;
audioCount =audioCount+1;
audioForce=audioForce+force;
if(audioCount>3){
//from 0-50 maps to 0.6 to 2
//rate=audioForce/audioCount*0.03+0.5;
//from 0-50 maps to 1 to 1.8
rate=(float) (audioForce/audioCount*0.012+1.0);
//myAlert(rate);
prvAudioRate=prvAudioRate+(rate-prvAudioRate)/3;
sm.setRate(prvAudioRate);
Log.i(TAG, "sm.setRate=" + prvAudioRate);
audioForce=0;
audioCount=0;
//prvAudioRate=rate;
}
}
private void setSensorListener() {
Log.i(TAG, "setSensorListener");
Sensor sensor = manager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
manager.registerListener(this, sensor, SensorManager.SENSOR_DELAY_GAME);
}
private void unSensorListener() {
Log.i(TAG, "unregisterListener");
manager.unregisterListener(this);
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.button:
setSensorListener();
break;
default:
break;
}
}
}
SoundControl.java
public class SoundControl {
public SoundPool mSoundPool;
private HashMap<Integer, Integer> mSoundPoolMap;
private AudioManager mAudioManager;
private Context mContext;
private int mStreamID;
static final String LOG_TAG = "SoundManager";
private boolean mSoundEnable = true;
private float mRate = 1f;
private boolean playing = false;
private int loopMode = 0;
private int mPlayIndex = -1;
public SoundControl(Context mContext) {
this.mContext = mContext;
mSoundPool = new SoundPool(4, AudioManager.STREAM_MUSIC, 0);
mSoundPoolMap = new HashMap<Integer, Integer>();
mAudioManager = (AudioManager) mContext.getSystemService(Context.AUDIO_SERVICE);
}
public void addSound(int index, String audioName) {
// mSoundPoolMap.put(1, mSoundPool.load(mContext, SoundID, 1));
try {
mSoundPoolMap.put(index, mSoundPool.load(mContext.getAssets().openFd(audioName), 1));
} catch (IOException e) {
e.printStackTrace();
}
}
// loopMode=0:play once; loopMode=-1:loop mode;
public void play(int index, int loopMode, float rate) {
if (mSoundEnable) {
this.loopMode = loopMode;
mRate = checkRate(rate);
int streamVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
// float streamVolume = 0.1f;
// notes: for loop mode, the priority should be set to 0, else it can't be stopped
// mStreamID=mSoundPool.play(mSoundPoolMap.get(index), streamVolume, streamVolume, 1, loopMode, mRate);
if (mPlayIndex < 0) {
mStreamID = mSoundPool.play(mSoundPoolMap.get(index), streamVolume, streamVolume, 0, loopMode, mRate);
} else {
mStreamID = mSoundPool.play(mSoundPoolMap.get(mPlayIndex), streamVolume, streamVolume, 0, loopMode, mRate);
}
playing = true;
}
}
// added for v 1.0.1, enable changing the audio remotely
public void setPlayIndex(int index) {
mPlayIndex = index;
}
public void setRate(float rate) {
if (mSoundEnable) {
mRate = checkRate(rate);
mSoundPool.setRate(mStreamID, mRate);
}
}
private float checkRate(float rate) {
if (rate > 2f) {
return 2f;
} else if (rate < 0.5f) {
return 0.5f;
} else {
return rate;
}
}
public void stepRate(float step) {
if (mSoundEnable) {
mRate = mRate + step;
mRate = checkRate(mRate);
mSoundPool.setRate(mStreamID, mRate);
}
}
public void pause() {
if (mSoundEnable) {
mSoundPool.pause(mStreamID);
// mSoundPool.autoPause();
}
}
public void resume() {
if (mSoundEnable) {
if (false == playing) {
play(1, loopMode, mRate);
} else {
mSoundPool.resume(mStreamID);
}
}
// mSoundPool.autoResume();
}
public void stop() {
if (mSoundEnable) {
playing = false;
mSoundPool.stop(mStreamID);
}
}
public void setSound(boolean soundEnable) {
mSoundEnable = soundEnable;
}
public void release() {
if (mSoundEnable) {
playing = false;
mSoundPool.release();
}
mSoundPool.release();
mSoundPool = null;
mSoundPoolMap.clear();
mSoundPoolMap = null;
}
}
现在我收到了新的错误：
致命的例外：主要 过程：com.example.leonzhang.clapapp，PID：9290 java.lang.NullPointerException：尝试调用虚方法＆＃39; int java.lang.Integer.intValue（）＆＃39;在null对象引用上 在com.example.leonzhang.clapapp.SoundControl.play（SoundControl.java:58） 在com.example.leonzhang.clapapp.MainActivity.onSensorChanged（MainActivity.java:56） 在android.hardware.SystemSensorManager $ SensorEventQueue.dispatchSensorEvent（SystemSensorManager.java:483） 在android.os.MessageQueue.nativePollOnce（本机方法） 在android.os.MessageQueue.next（MessageQueue.java:323） 在android.os.Looper.loop（Looper.java:135） 在android.app.ActivityThread.main（ActivityThread.java:5417） at java.lang.reflect.Method.invoke（Native Method） 在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run（ZygoteInit.java:764） 在com.android.internal.os.ZygoteInit.main（ZygoteInit.java:626）