在Android Studio中使用传感器数据更改音量

我试图用指南针的方位测量值来改变音量。每当我使用与卷相关的任何内容时，就会出现未知问题，当我运行应用程序时，它会立即打开和关闭。我目前正在将音量设置为零，因为我还不知道允许音量的范围。代码应将方位角0-360映射为体积百分比0-100。这个想法是在声音随角度变化的地方播放音乐

package com.example.compass;

import androidx.appcompat.app.AppCompatActivity;
import android.hardware.Sensor;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.view.animation.Animation;
import android.view.animation.RotateAnimation;
import android.widget.ImageView;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.widget.Button;
import android.view.View;
import android.widget.TextView;
import android.media.AudioManager;

public class MainActivity extends AppCompatActivity implements SensorEventListener {

    private ImageView imageView;
    private float[] mGravity = new float[3];
    private float[] mGeomagnetic = new float[3];
    private float azimuth = 0f;
    private float currectAzimuth = 0f;
    private SensorManager mSensorManager;
    private TextView mTextViewResult;
    private AudioManager audioManager = null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mTextViewResult = findViewById(R.id.textview_result);

        imageView = (ImageView)findViewById(R.id.compass);
        mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
    }
    @Override
    protected void onResume(){
        super.onResume();
        mSensorManager.registerListener(this,mSensorManager.getDefaultSensor(Sensor.TYPE_MAGNETIC_FIELD),
                SensorManager.SENSOR_DELAY_GAME);
        mSensorManager.registerListener(this,mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER),
                SensorManager.SENSOR_DELAY_GAME);
    }

    @Override
    protected void onPause(){
        super.onPause();
        mSensorManager.unregisterListener(this);
    }
    @Override
    public void onSensorChanged(SensorEvent sensorEvent){
        final float alpha = 0.97f;
        synchronized (this){
            if(sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER)
            {
                mGravity[0] = alpha*mGravity[0]+(1-alpha)*sensorEvent.values[0];
                mGravity[1] = alpha*mGravity[1]+(1-alpha)*sensorEvent.values[1];
                mGravity[2] = alpha*mGravity[2]+(1-alpha)*sensorEvent.values[2];
            }
            if(sensorEvent.sensor.getType() == Sensor.TYPE_MAGNETIC_FIELD)
            {
                mGeomagnetic[0] = alpha*mGeomagnetic[0]+(1-alpha)*sensorEvent.values[0];
                mGeomagnetic[1] = alpha*mGeomagnetic[1]+(1-alpha)*sensorEvent.values[1];
                mGeomagnetic[2] = alpha*mGeomagnetic[2]+(1-alpha)*sensorEvent.values[2];
            }
            float R[] = new float[9];
            float I[] = new float[9];
            boolean success = SensorManager.getRotationMatrix(R,I,mGravity,mGeomagnetic);
            if (success){
                float orientation[] = new float[3];
                SensorManager.getOrientation(R,orientation);
                azimuth = (float)Math.toDegrees(orientation[0]);
                azimuth = (azimuth+360)%360;
                //
                Animation anim = new RotateAnimation(-currectAzimuth,-azimuth, Animation.RELATIVE_TO_SELF,0.5f,Animation.RELATIVE_TO_SELF,0.5f);
                currectAzimuth = azimuth;

                mTextViewResult.setText(String.valueOf(Math.round(currectAzimuth)));
                //anything related to the volume breaks the program
                audioManager.setStreamVolume(AudioManager.STREAM_MUSIC,
                        Math.round(0), 0);
                //
                anim.setDuration(500);
                anim.setRepeatCount(0);
                anim.setFillAfter(true);
                imageView.startAnimation(anim);
            }
        }
    }
    @Override
    public void onAccuracyChanged(Sensor sensor, int i){

    }
}

---

问题已经解决了。我认为问题在于我重新安装的虚拟设备。

这意味着它正在崩溃。Android已经生成了一个stacktrace，它会准确地告诉你问题出在哪里。检查logcat。在没有堆栈跟踪的情况下调试崩溃是非常困难的。请参阅，以获取特定于Android的建议，以及获得堆栈跟踪后的操作建议。如果仍然需要帮助，请编辑问题以包含完整的堆栈跟踪以及堆栈跟踪指向的代码行。