I got the following problem in Android Studio. I tried to rebuild an Google Android Guide for using the light sensor. While typing the code I got this error from Android Studio. It says Unresolved reference: event I don't know how to handle it. It is one of my first tries using kotlin in Android Studio.

Can anyone show me how to fix it?

I am using Android Studio Version 2021.3.1 Patch 1 on Mac OS X Catalina

I am thankful for any help.

enter image description here

Here is my Code:

package eu.jnaberle.myapplication

import android.app.Activity
import android.hardware.Sensor
import android.hardware.SensorEvent
import android.hardware.SensorEventListener
import android.hardware.SensorManager
import androidx.appcompat.app.AppCompatActivity
import android.os.Bundle


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

class SensorActivity : Activity(), SensorEventListener {
    private lateinit var sensorManager: SensorManager
    private var mLight: Sensor? = null

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

        sensorManager = getSystemService(SENSOR_SERVICE) as SensorManager
        mLight = sensorManager.getDefaultSensor(Sensor.TYPE_LIGHT)
    }

    override fun onAccuracyChanged(p0: Sensor?, p1: Int) {
        TODO("Not yet implemented")
    }

    override fun onSensorChanged(p0: SensorEvent?) {
        val lux = event.values[0]
    }

    override fun onResume() {
        super.onResume()
        mLight?.also { light ->
            sensorManager.registerListener(this, light, SensorManager.SENSOR_DELAY_NORMAL)
        }
    }

    override fun onPause() {
        super.onPause()
        sensorManager.unregisterListener(this)
    }
}

Tried to build the program after the instruction. Also watched some YouTube Tutorials, but I don't understand, and thay didn't worked for me.

CodePudding user response：

If I'm not mistaken you might be using this as your resource, and if you take a closer look:

override fun onSensorChanged(event: SensorEvent) {
    // The light sensor returns a single value.
    // Many sensors return 3 values, one for each axis.
    val lux = event.values[0]
    // Do something with this sensor value.
}

it is different than your implementation:

override fun onSensorChanged(p0: SensorEvent?) {
    val lux = event.values[0]
}

just rename the p0 parameter to event

CodePudding user response：

Copy my onSensorChanged method and replace with Your

override fun onSensorChanged(p0: SensorEvent?) {
        val lux = p0.values[0]
    }