I am trying to develop a simple app that outputs the temperature using a SensorManager to read and set the value from the temperature sensor. But whenever I run the code, nothing outputs, and I get a message saying the SensorManager keeps stopping. Can someone please point out what the root of the problem is? Here is my code:
MainActivity.java
package com.zybooks.sensormanager;
import androidx.appcompat.app.AppCompatActivity;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;
import android.os.Bundle;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity implements SensorEventListener {
private SensorManager sensorManager;
private Sensor thermometer;
private TextView tempValues;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
thermometer = sensorManager.getDefaultSensor(Sensor.TYPE_AMBIENT_TEMPERATURE);
tempValues = findViewById(R.id.temperatureValues);
}
@Override
public final void onAccuracyChanged(Sensor sensor, int accuracy) {
// Do something here if sensor accuracy changes.
}
@Override
public final void onSensorChanged(SensorEvent event) {
tempValues.setText((int) event.values[0]);
}
@Override
protected void onResume() {
// Register a listener for the sensor.
super.onResume();
sensorManager.registerListener(this, thermometer, SensorManager.SENSOR_DELAY_NORMAL);
}
@Override
protected void onPause() {
// Be sure to unregister the sensor when the activity pauses.
super.onPause();
sensorManager.unregisterListener(this, thermometer);
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.appcompat.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="419dp"
android:layout_height="91dp"
android:background="?attr/colorPrimary"
android:minHeight="?attr/actionBarSize"
android:theme="?attr/actionBarTheme"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
<TextView
android:id="@+id/barTitle"
android:layout_width="179dp"
android:layout_height="36dp"
android:layout_marginBottom="23dp"
android:text="Thermometer"
android:textColor="#8BC34A"
android:textSize="24sp"
app:layout_constraintBottom_toBottomOf="@+id/toolbar"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="@+id/toolbar" />
<TextView
android:id="@+id/temperatureValues"
android:layout_width="191dp"
android:layout_height="77dp"
android:text="Temperature"
android:textAlignment="center"
android:textSize="24sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/toolbar"
app:layout_constraintVertical_bias="0.44" />
</androidx.constraintlayout.widget.ConstraintLayout>
It looks like replacing the code in the onSensorChanged function with this code solved my problem:
float ambient_temperature = event.values[0];
tempValues.setText("Temperature:\n " + String.valueOf(ambient_temperature));
Plus, I had to move the bar in my virtual sensor so a number would actually output.