Using sensor data to change volume in Android Studio

Question

I am trying to use the azimuth measurements of a compass to change the volume. An unknown issue occurs whenever I use anything related to the volume where, when I run the app, it opens and closes immediately. I am currently setting the volume to zero, as I do not know the range of allowable volumes yet. The code should map the azimuth angles (0-360) to a volume percentage (0-100). The idea is to play music where the sound changes with the angle.

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){

    }
}

This means it is _crashing_. Android has produced a stacktrace that will tell you exactly where the problem is. Check logcat. — greeble31, Dec 01 '19 at 22:32
It's very difficult to debug a crash without a stack trace. See [Unfortunately MyApp has stopped. How can I solve this?](https://stackoverflow.com/questions/23353173) for Android-specific advice, and [What is a stack trace, and how can I use it to debug my application errors?](https://stackoverflow.com/questions/3988788) for advice on what to do once you have the stack trace. If you still need help, edit your question to include the **complete stack trace**, as well as **which line of your code** the stack trace points to. — Ryan M, Mar 22 '20 at 18:37

score 1 · Accepted Answer · answered Mar 23 '20 at 10:52

1

The problem has been resolved. I believe the issue was the virtual device, which I reinstalled.

answered Mar 23 '20 at 10:52

gilianzz

199
2
14

Using sensor data to change volume in Android Studio

1 Answers1