How to Build a Sensor App in Android?

Android mobile phones have sensors, so we can perform various functions like Controlling screen brightness, Monitoring acceleration along a single axis, Motion detection, etc. In this article, we will be building an application that will determine the intensity of light in the room with the help of light sensors. A sample video is given below to get an idea about what we are going to do in this article.

Step by Step Implementation

Step 1: Create a New Project in Android Studio

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Note that select Kotlin as the programming language.

Step 2: Add permission to access sensors 

Add this line inside the AndroidManifest.xml file add this line

XML

<uses-feature android:name="android.hardware.sensor.accelerometer" android:required="true" />

Step 3: Add Circular progress bar dependency inside  build.gradle(app) file

Kotlin

implementation 'com.mikhaellopez:circularprogressbar:3.1.0'

Step 4: Working with the activity_main.xml file

Navigate to the app > res > layout > activity_main.xml and add the below code to that file. Below is the code for the activity_main.xml file. We are using the Circular ProgressBar in this project which will change its color when the intensity of light changes.

XML

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    android:gravity="center_horizontal"
    android:orientation="vertical"
    android:background="#000"
    tools:context=".MainActivity">

    <RelativeLayout
        android:id="@+id/progress_layout"
        android:layout_width="200dp"
        android:layout_height="200dp"
        android:layout_margin="100dp">

        <com.mikhaellopez.circularprogressbar.CircularProgressBar
            android:id="@+id/circularProgressBar"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:cpb_background_progressbar_color="#b6bbd8"
            app:cpb_background_progressbar_width="5dp"
            app:cpb_progress_direction="to_right"
            app:cpb_progressbar_color="#3f51b5"
            app:cpb_progressbar_width="10dp"
            app:cpb_round_border="false" />

        <!--Text implementation in center
            of the progress bar-->
        <TextView
            android:id="@+id/intensity"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentLeft="true"
            android:layout_alignParentRight="true"
            android:layout_centerVertical="true"
            android:gravity="center"
            android:textColor="#ffff"
            android:textSize="28sp"
            android:textStyle="bold" />
    </RelativeLayout>

    <TextView
        android:id="@+id/available"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:visibility="invisible">
    </TextView>

    <TextView
        android:id="@+id/light"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:textAlignment="center"
        android:textColor="#ffff">
    </TextView>

</LinearLayout>

Step 5: Working with the MainActivity.kt file

Go to the MainActivity.kt file and refer to the following code. Below is the code for the MainActivity.kt file. As the last step, we will be writing Kotlin code inside MainActivity.kt file. We can use the if else condition and display the message inside the text view according to the intensity of light in the room. Similarly, we can change the color of the ProgressBar according to the intensity of light.

Kotlin

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val mySensorManager = getSystemService(SENSOR_SERVICE) as SensorManager
        val lightSensor = mySensorManager.getDefaultSensor(Sensor.TYPE_LIGHT)
        if (lightSensor != null) {
            available!!.text = "LIGHT Available"
            mySensorManager.registerListener(
                lightSensorListener,
                lightSensor,
                SensorManager.SENSOR_DELAY_NORMAL
            )
        } else {
            available!!.text = "LIGHT NOT Available"
        }
    }

    private val lightSensorListener: SensorEventListener = object : SensorEventListener {
        override fun onAccuracyChanged(sensor: Sensor, accuracy: Int) {
            // TODO Auto-generated method stub
        }

        override fun onSensorChanged(event: SensorEvent) {
            if (event.sensor.type == Sensor.TYPE_LIGHT) {
                intensity!!.text = "" + event.values[0]

                if (event.values[0] in 0.0..50.0) {
                    light!!.text = "Switch On Lights"

                    circularProgressBar.apply {
                        // Set Progress
                        progress = 65f

                        // or with animation
                        setProgressWithAnimation(65f, 1000) // =1s

                        // Set Progress Max
                        progressMax = 200f

                        // Set ProgressBar Color
                        progressBarColor = Color.BLACK

                        // or with gradient
                        progressBarColorStart = Color.GRAY
                        progressBarColorEnd = Color.WHITE
                        progressBarColorDirection =
                            CircularProgressBar.GradientDirection.TOP_TO_BOTTOM

                        // Set background ProgressBar Color
                        backgroundProgressBarColor = Color.GRAY

                        // or with gradient
                        backgroundProgressBarColorStart = Color.WHITE
                        backgroundProgressBarColorEnd = Color.WHITE
                        backgroundProgressBarColorDirection =
                            CircularProgressBar.GradientDirection.TOP_TO_BOTTOM

                        // Set Width
                        progressBarWidth = 7f // in DP
                        backgroundProgressBarWidth = 3f // in DP

                        // Other
                        roundBorder = true
                        startAngle = 180f
                        progressDirection = CircularProgressBar.ProgressDirection.TO_RIGHT
                    }

                } else if (event.values[0] in 50.0..100.0) {

                    light!!.text = "Dim Light"
                    circularProgressBar.apply {
                        // Set Progress
                        progress = 65f

                        // or with animation
                        setProgressWithAnimation(65f, 1000) // =1s

                        // Set Progress Max
                        progressMax = 200f

                        // Set ProgressBar Color
                        progressBarColor = Color.BLACK

                        // or with gradient
                        progressBarColorStart = Color.GRAY
                        progressBarColorEnd = Color.RED
                        progressBarColorDirection =
                            CircularProgressBar.GradientDirection.TOP_TO_BOTTOM

                        // Set background ProgressBar Color
                        backgroundProgressBarColor = Color.GRAY

                        // or with gradient
                        backgroundProgressBarColorStart = Color.WHITE
                        backgroundProgressBarColorEnd = Color.WHITE
                        backgroundProgressBarColorDirection =
                            CircularProgressBar.GradientDirection.TOP_TO_BOTTOM

                        // Set Width
                        progressBarWidth = 7f // in DP
                        backgroundProgressBarWidth = 3f // in DP

                        // Other
                        roundBorder = true
                        startAngle = 180f
                        progressDirection = CircularProgressBar.ProgressDirection.TO_RIGHT
                    }
                } else if (event.values[0] in 100.0..200.0) {
                    light!!.text = "Bright Light"

                    circularProgressBar.apply {
                        // Set Progress
                        progress = 65f

                        // or with animation
                        setProgressWithAnimation(65f, 20000) // =2s

                        // Set Progress Max
                        progressMax = 200f

                        // Set ProgressBar Color
                        progressBarColor = Color.BLACK

                        // or with gradient
                        progressBarColorStart = Color.GRAY
                        progressBarColorEnd = Color.RED
                        progressBarColorDirection =
                            CircularProgressBar.GradientDirection.TOP_TO_BOTTOM

                        // Set background ProgressBar Color
                        backgroundProgressBarColor = Color.GRAY

                        // or with gradient
                        backgroundProgressBarColorStart = Color.WHITE
                        backgroundProgressBarColorEnd = Color.RED
                        backgroundProgressBarColorDirection =
                            CircularProgressBar.GradientDirection.TOP_TO_BOTTOM

                        // Set Width
                        progressBarWidth = 7f // in DP
                        backgroundProgressBarWidth = 3f // in DP

                        // Other
                        roundBorder = true
                        startAngle = 180f
                        progressDirection = CircularProgressBar.ProgressDirection.TO_RIGHT
                    }

                } else {

                    circularProgressBar.apply {
                        light!!.text = "Very Bright Light"
                        progress = 65f

                        // or with animation
                        setProgressWithAnimation(65f, 1000) // =1s

                        // Set Progress Max
                        progressMax = 200f

                        // Set ProgressBar Color
                        progressBarColor = Color.BLACK

                        // or with gradient
                        progressBarColorStart = Color.GRAY
                        progressBarColorEnd = Color.RED
                        progressBarColorDirection =
                            CircularProgressBar.GradientDirection.TOP_TO_BOTTOM

                        // Set background ProgressBar Color
                        backgroundProgressBarColor = Color.GRAY

                        // or with gradient
                        backgroundProgressBarColorStart = Color.WHITE
                        backgroundProgressBarColorEnd = Color.MAGENTA
                        backgroundProgressBarColorDirection =
                            CircularProgressBar.GradientDirection.TOP_TO_BOTTOM

                        // Set Width
                        progressBarWidth = 7f // in DP
                        backgroundProgressBarWidth = 3f // in DP

                        // Other
                        roundBorder = true
                        startAngle = 180f
                        progressDirection = CircularProgressBar.ProgressDirection.TO_RIGHT
                    }
                }
            }
        }
    }
}

Output: