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Android Studio (Log Sensor Data to csv. File)

I have to log my Sensor data from my Android Phone to a csv. file so I can use it further , the problem is I tried something with some code(FileWriter to csv) that I found and put it into my code and it does not work, can maybe someone tell me what I do wrong, where my error is. The idea is to just record different sensor data with different EventHandlers like in the Code Example and then write the sensor data to a csv. file together and that csv. file should be on the phone.
I have maybe to mention that I have never before programed in Java or did Android , so please try to answer me as simple as possible, thank you :)
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.util.Log;
import android.widget.CompoundButton;
import android.widget.ProgressBar;
import android.widget.Switch;
import android.widget.TextView;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
TextView txt_currentAccel, txt_prevAccel, txt_acceleration, txt_temp;
ProgressBar prog_shakeMeter;
Switch switch1;
//define Sensor Variables
private SensorManager mSensorManager;
private Sensor mAccelerometer;
private SensorManager mSensorManagerNew;
private Sensor mTemp;
private double accelerationCurrentValue;
private double accelerationPreviousValue;
private int SwitchFlag = 0;
final String TAG = "SensorLog";
FileWriter writer;
private SensorEventListener sensorEventListener = new SensorEventListener() {
#Override
public void onSensorChanged(SensorEvent sensorEvent) {
if (sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER && SwitchFlag == 1) {
float x = sensorEvent.values[0];
float y = sensorEvent.values[1];
float z = sensorEvent.values[2];
accelerationCurrentValue = Math.sqrt((x * x + y * y + z * z));
double changeInAcceleration = Math.abs(accelerationCurrentValue - accelerationPreviousValue);
accelerationPreviousValue = accelerationCurrentValue;
//update text views
txt_currentAccel.setText("Current =" + accelerationCurrentValue);
txt_prevAccel.setText(("Prev = " + accelerationPreviousValue));
txt_acceleration.setText("Acceleration change =" + changeInAcceleration);
prog_shakeMeter.setProgress((int) changeInAcceleration);
try {
writer.write(String.format("ACC; %f; %f; %f; %f; %f; %f\n", sensorEvent.values[0], sensorEvent.values[1], sensorEvent.values[2], 0.f, 0.f, 0.f));
}catch (IOException e) {
e.printStackTrace();
}
}
}
#Override
public void onAccuracyChanged(Sensor sensor, int i) {
}
};
private SensorEventListener sensorEventListenerNew = new SensorEventListener() {
#Override
public void onSensorChanged(SensorEvent sensorEvent) {
float temp = sensorEvent.values[0];
txt_temp.setText("Temp = " + temp);
}
#Override
public void onAccuracyChanged(Sensor sensor, int i) {
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txt_acceleration = findViewById(R.id.txt_accel);
txt_prevAccel = findViewById(R.id.txt_prevAccel);
txt_currentAccel = findViewById(R.id.txt_currentAccel);
txt_temp = findViewById(R.id.txt_temp);
prog_shakeMeter = findViewById(R.id.prog_shakeMeter);
switch1 = findViewById(R.id.switch1);
// Initialize Sensors
mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mSensorManagerNew = (SensorManager) getSystemService(SENSOR_SERVICE);
mTemp = mSensorManagerNew.getDefaultSensor(Sensor.TYPE_LIGHT);
switch1.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (b == true) {
SwitchFlag = 1;
} else {
SwitchFlag = 0;
}
}
});
}
public void flag() {
if (SwitchFlag == 1) {
Log.d(TAG, "Writing to " + getStorageDir());
try {
writer = new FileWriter(new File(getStorageDir(), "sensors_" + System.currentTimeMillis() + ".csv"));
} catch (
IOException e) {
e.printStackTrace();
}
} else {
try {
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
protected void onResume() {
super.onResume();
mSensorManager.registerListener(sensorEventListenerNew, mTemp, SensorManager.SENSOR_DELAY_NORMAL);
mSensorManager.registerListener(sensorEventListener, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
}
protected void onPause() {
super.onPause();
mSensorManager.unregisterListener(sensorEventListener);
mSensorManager.unregisterListener(sensorEventListenerNew);
}
private String getStorageDir() {
return this.getExternalFilesDir(null).getAbsolutePath();
}
}

Android: Save CSV File to internal Storage

I have put somehow together a code that records my sensor data from the phone and i want to save them as csv file in some directory (maybe DCIM) in the internal Storage on the phone, but i cannot find something similar, i am also new to Android Studio and java.
On the bottom you can see ,i found that code example with
"getExternalFilesDir(null).getAbsolutePath()" , how can i change that , that my file is saved on the phone in internal storage and tell him exactly where so i can find it later and use it further ?
package com.example.shakedemo;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Context;
import android.content.Intent;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.util.Log;
import android.widget.CompoundButton;
import android.widget.ProgressBar;
import android.widget.Switch;
import android.widget.TextView;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
public class MainActivity extends AppCompatActivity {
TextView txt_currentAccel, txt_prevAccel, txt_acceleration, txt_temp;
ProgressBar prog_shakeMeter;
Switch switch1;
//define Sensor Variables
private SensorManager mSensorManager;
private Sensor mAccelerometer;
private SensorManager mSensorManagerNew;
private Sensor mTemp;
private double accelerationCurrentValue;
private double accelerationPreviousValue;
private int SwitchFlag = 0;
final String TAG = "SensorLog";
FileWriter writer;
private SensorEventListener sensorEventListener = new SensorEventListener() {
#Override
public void onSensorChanged(SensorEvent sensorEvent) {
if (sensorEvent.sensor.getType() == Sensor.TYPE_ACCELEROMETER && SwitchFlag == 1) {
float x = sensorEvent.values[0];
float y = sensorEvent.values[1];
float z = sensorEvent.values[2];
accelerationCurrentValue = Math.sqrt((x * x + y * y + z * z));
double changeInAcceleration = Math.abs(accelerationCurrentValue - accelerationPreviousValue);
accelerationPreviousValue = accelerationCurrentValue;
//update text views
txt_currentAccel.setText("Current =" + accelerationCurrentValue);
txt_prevAccel.setText(("Prev = " + accelerationPreviousValue));
txt_acceleration.setText("Acceleration change =" + changeInAcceleration);
prog_shakeMeter.setProgress((int) changeInAcceleration);
try {
writer.write(String.format("ACC; %f; %f; %f; %f; %f; %f\n", sensorEvent.values[0], sensorEvent.values[1], sensorEvent.values[2], 0.f, 0.f, 0.f));
}catch (IOException e) {
e.printStackTrace();
}
}
}
#Override
public void onAccuracyChanged(Sensor sensor, int i) {
}
};
private SensorEventListener sensorEventListenerNew = new SensorEventListener() {
#Override
public void onSensorChanged(SensorEvent sensorEvent) {
float temp = sensorEvent.values[0];
txt_temp.setText("Temp = " + temp);
}
#Override
public void onAccuracyChanged(Sensor sensor, int i) {
}
};
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
txt_acceleration = findViewById(R.id.txt_accel);
txt_prevAccel = findViewById(R.id.txt_prevAccel);
txt_currentAccel = findViewById(R.id.txt_currentAccel);
txt_temp = findViewById(R.id.txt_temp);
prog_shakeMeter = findViewById(R.id.prog_shakeMeter);
switch1 = findViewById(R.id.switch1);
// Initialize Sensors
mSensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
mAccelerometer = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mSensorManagerNew = (SensorManager) getSystemService(SENSOR_SERVICE);
mTemp = mSensorManagerNew.getDefaultSensor(Sensor.TYPE_LIGHT);
switch1.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
#Override
public void onCheckedChanged(CompoundButton compoundButton, boolean b) {
if (b == true) {
Log.d(TAG, "Writing to " + getStorageDir());
try {
writer = new FileWriter(new File(getStorageDir(), "sensors_" + System.currentTimeMillis() + ".csv"));
} catch (
IOException e) {
e.printStackTrace();
}
SwitchFlag = 1;
} else {
try {
writer.close();
} catch (IOException e) {
e.printStackTrace();
}
SwitchFlag = 0;
}
}
});
}
protected void onResume() {
super.onResume();
mSensorManager.registerListener(sensorEventListenerNew, mTemp, SensorManager.SENSOR_DELAY_NORMAL);
mSensorManager.registerListener(sensorEventListener, mAccelerometer, SensorManager.SENSOR_DELAY_NORMAL);
}
protected void onPause() {
super.onPause();
mSensorManager.unregisterListener(sensorEventListener);
mSensorManager.unregisterListener(sensorEventListenerNew);
}
private String getStorageDir() {
return this.getExternalFilesDir(null).getAbsolutePath();
}
}

My Android app is crashing in the emulator

My app is crashing. I am trying to build an accelerometer based app. Though build is successful, it is not running in the Pixel Emulator. Where have I gone wrong?
I have been trying to find the error but am unsuccessful. I am attaching the run error message, the screenshot of the manifest file and the main code.
This is the error message:
The main code follows
package com.example.androidaccelerometerexample;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.app.Activity;
import android.text.Html;
import android.view.Menu;
import android.widget.TextView;
import android.app.Activity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.os.Vibrator;
import android.widget.TextView;
class Main extends Activity implements SensorEventListener {
private float lastX, lastY, lastZ;
private SensorManager sensorManager;
private Sensor accelerometer;
private float deltaXMax = 0;
private float deltaYMax = 0;
private float deltaZMax = 0;
private float deltaX = 0;
private float deltaY = 0;
private float deltaZ = 0;
private float vibrateThreshold = 0;
private TextView currentX, currentY, currentZ, maxX, maxY, maxZ;
public Vibrator v;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initializeViews();
sensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
if (sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER) != null) {
// success! we have an accelerometer
accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
vibrateThreshold = accelerometer.getMaximumRange() / 2;
} else {
// fai! we dont have an accelerometer!
}
//initialize vibration
v = (Vibrator) this.getSystemService(Context.VIBRATOR_SERVICE);
}
public void initializeViews() {
currentX = (TextView) findViewById(R.id.currentX);
currentY = (TextView) findViewById(R.id.currentY);
currentZ = (TextView) findViewById(R.id.currentZ);
maxX = (TextView) findViewById(R.id.maxX);
maxY = (TextView) findViewById(R.id.maxY);
maxZ = (TextView) findViewById(R.id.maxZ);
}
protected void onResume() {
super.onResume();
sensorManager.registerListener(this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
}
protected void onPause() {
super.onPause();
sensorManager.unregisterListener(this);
}
#Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
}
#Override
public void onSensorChanged(#org.jetbrains.annotations.NotNull SensorEvent event) {
// clean current values
displayCleanValues();
// display the current x,y,z accelerometer values
displayCurrentValues();
// display the max x,y,z accelerometer values
displayMaxValues();
// get the change of the x,y,z values of the accelerometer
deltaX = Math.abs(lastX - event.values[0]);
deltaY = Math.abs(lastY - event.values[1]);
deltaZ = Math.abs(lastZ - event.values[2]);
// if the change is below 2, it is just plain noise
if (deltaX < 2)
deltaX = 0;
if (deltaY < 2)
deltaY = 0;
if ((deltaZ > vibrateThreshold) || (deltaY > vibrateThreshold) || (deltaX > vibrateThreshold)) {
v.vibrate(50);
}
}
public void displayCleanValues() {
currentX.setText("0.0");
currentY.setText("0.0");
currentZ.setText("0.0");
}
// display the current x,y,z accelerometer values
public void displayCurrentValues() {
currentX.setText(Float.toString(deltaX));
currentY.setText(Float.toString(deltaY));
currentZ.setText(Float.toString(deltaZ));
}
// display the max x,y,z accelerometer values
public void displayMaxValues() {
if (deltaX > deltaXMax) {
deltaXMax = deltaX;
maxX.setText(Float.toString(deltaXMax));
}
if (deltaY > deltaYMax) {
deltaYMax = deltaY;
maxY.setText(Float.toString(deltaYMax));
}
if (deltaZ > deltaZMax) {
deltaZMax = deltaZ;
maxZ.setText(Float.toString(deltaZMax));
}
}
}

Your activity class needs to be public and not package-private.
Change class Main to public class Main.

Followed tutorial on creating a shake listener, having trouble using it

I'm simply trying to learn android using baby-steps. I've followed a tutorial on how to implement a "shake listener" from this tutorial
This is it:
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.FloatMath;
public class ShakeListener implements SensorEventListener {
/*
* The gForce that is necessary to register as shake.
* Must be greater than 1G (one earth gravity unit).
* You can install "G-Force", by Blake La Pierre
* from the Google Play Store and run it to see how
* many G's it takes to register a shake
*/
private static final float SHAKE_THRESHOLD_GRAVITY = 2.7F;
private static final int SHAKE_SLOP_TIME_MS = 500;
private static final int SHAKE_COUNT_RESET_TIME_MS = 3000;
private OnShakeListener mListener;
private long mShakeTimestamp;
private int mShakeCount;
public void setOnShakeListener(OnShakeListener listener) {
this.mListener = listener;
}
public interface OnShakeListener {
public void onShake(int count);
}
#Override
public void onAccuracyChanged(Sensor sensor, int accuracy) {
// ignore
}
#Override
public void onSensorChanged(SensorEvent event) {
if (mListener != null) {
float x = event.values[0];
float y = event.values[1];
float z = event.values[2];
float gX = x / SensorManager.GRAVITY_EARTH;
float gY = y / SensorManager.GRAVITY_EARTH;
float gZ = z / SensorManager.GRAVITY_EARTH;
// gForce will be close to 1 when there is no movement.
float gForce = FloatMath.sqrt(gX * gX + gY * gY + gZ * gZ);
if (gForce > SHAKE_THRESHOLD_GRAVITY) {
final long now = System.currentTimeMillis();
// ignore shake events too close to each other (500ms)
if (mShakeTimestamp + SHAKE_SLOP_TIME_MS > now) {
return;
}
// reset the shake count after 3 seconds of no shakes
if (mShakeTimestamp + SHAKE_COUNT_RESET_TIME_MS < now) {
mShakeCount = 0;
}
mShakeTimestamp = now;
mShakeCount++;
mListener.onShake(mShakeCount);
}
}
}
}
I read jokes from a folder and I'd like to display a new one every time I shake the phone. I have no idea how to call the shake listener.
private SensorManager mSensorManager;
private Sensor mAccelerometer;
private ShakeListener mShakeListener;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Intent intent = getIntent();
String message = intent.getStringExtra(MainActivity.EXTRA_MESSAGE);
TextView textView = new TextView(this);
textView.setTextSize(16);
String[] test = processData(readText(message));
textView.setText(test[0]); // later will use random
//________________________________________________
// THIS IS THE PART I HAVE NO IDEA HOW TO IMPLEMENT.
while (true) {
if (shake)
textView.setText(test[RandomNumber]);
}
//________________________________________________
setContentView(textView);
}
I think this is what I should use, but frankly I don't understand what's going on:
// ShakeListener initialization
mSensorManager = (SensorManager) getSystemService(Context.SENSOR_SERVICE);
mAccelerometer = mSensorManager
.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
mShakeListener = new ShakeListener();
mShakeListener.setOnShakeListener(new OnShakeListener() {
#Override
public void onShake(int count) {
/*
* The following method, "handleShakeEvent(count):" is a stub //
* method you would use to setup whatever you want done once the
* device has been shook.
*/
handleShakeEvent(count);
}
});

You don't call Listeners. They call you.
Move:
while (true) {
if (shake)
textView.setText(test[RandomNumber]); // this line
}
to:
#Override
public void onShake(int count) {
/*
* HERE
*/
handleShakeEvent(count);
}
Should achieve what you're aiming for.

ShakeListener implementation in separate class

I'm trying to implement a ShakeListener. So I made a Class called ShakeListener.java :
import java.util.List;
import android.app.Activity;
import android.content.Context;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.util.Log;
public class ShakeListener implements SensorEventListener {
private SensorManager sensorManager;
private List<Sensor> sensors;
private Sensor sensor;
private long lastUpdate = -1;
private long currentTime = -1;
private float last_x, last_y, last_z;
private float current_x, current_y, current_z, currenForce;
private static final int FORCE_THRESHOLD = 900;
private final int DATA_X = SensorManager.DATA_X;
private final int DATA_Y = SensorManager.DATA_Y;
private final int DATA_Z = SensorManager.DATA_Z;
public ShakeListener(Activity parent) {
SensorManager sensorService = (SensorManager) parent
.getSystemService(Context.SENSOR_SERVICE);
this.sensorManager = sensorManager;
this.sensors = sensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER);
if (sensors.size() > 0) {
sensor = sensors.get(0);
}
}
public void start() {
if (sensor != null) {
sensorManager.registerListener(this, sensor,
SensorManager.SENSOR_DELAY_GAME);
}
}
public void stop() {
sensorManager.unregisterListener(this);
}
public void onAccuracyChanged(Sensor s, int valu) {
}
public void onSensorChanged(SensorEvent event) {
if (event.sensor.getType() != Sensor.TYPE_ACCELEROMETER
|| event.values.length < 3)
return;
currentTime = System.currentTimeMillis();
if ((currentTime - lastUpdate) > 100) {
long diffTime = (currentTime - lastUpdate);
lastUpdate = currentTime;
current_x = event.values[DATA_X];
current_y = event.values[DATA_Y];
current_z = event.values[DATA_Z];
currenForce = Math.abs(current_x + current_y + current_z - last_x
- last_y - last_z)
/ diffTime * 10000;
if (currenForce > FORCE_THRESHOLD) {
Log.d("ShakeListener", "SHAKE DETECTED");
}
last_x = current_x;
last_y = current_y;
last_z = current_z;
}
}
}
Now, I want to envoke it from my main activity (thinking about implementing a While-loop that waits for a shake boolean to change?). So in my main activity, I use :
private ShakeListener myShakeListener;
and then
myShakeListener = new ShakeListener(this);
myShakeListener.start();
But I get an NPE on the line :
this.sensors = sensorManager.getSensorList(Sensor.TYPE_ACCELEROMETER);
What am I doing wrong? How should I implement this?

Look at sensorService. It is wrong. Change your code:
SensorManager sensorService = (SensorManager) parent
.getSystemService(Context.SENSOR_SERVICE);
this.sensorManager = sensorManager;
to
SensorManager sensorService = (SensorManager) parent
.getSystemService(Context.SENSOR_SERVICE);
this.sensorManager = sensorService ;
or a better code:
this.sensorManager = (SensorManager) parent.getSystemService(Context.SENSOR_SERVICE);