Sensor Based Flash On and Off

Sensor Based Flash On and Off

MainActivity.java

package com.example.secondapp;

import androidx.appcompat.app.AppCompatActivity;

import android.hardware.Camera;
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.TextView;

import java.util.List;

public class MainActivity extends AppCompatActivity {
    private SensorManager sm;
    private TextView mydata;
    private Camera camera;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mydata = findViewById(R.id.data);
        //how to get sensormanager object
        sm = (SensorManager) getSystemService(SENSOR_SERVICE);
        /*List<Sensor> slist = sm.getSensorList(Sensor.TYPE_ALL);
        for (Sensor s : slist) {
            Log.e("error", s.getName());
            Log.e("error", s.getType() + "");
        }*/

        Sensor s = sm.getDefaultSensor(Sensor.TYPE_PROXIMITY);
        if (s != null) {
            sm.registerListener(se, s, 

        SensorManager.SENSOR_DELAY_NORMAL);
        }


    }

    SensorEventListener se = new SensorEventListener() {
        @Override
        public void onSensorChanged(SensorEvent sensorEvent) {
            //Log.e("error", "sensor");
            float value[] = sensorEvent.values;
            //Log.e("error0", value[0] + "\t" + value[1] + "\t" + value[2]);
            mydata.setText(String.valueOf(value[0]));
            if (value[0] == 0.0f) {
                mydata.setText("near");
                flashOn();
            } else {
                mydata.setText("so far");
                flashOff();
            }
        }

        @Override
        public void onAccuracyChanged(Sensor sensor, int i) {
            Log.e("error", "accuracy");
        }
    };

    @Override
    protected void onStop() {
        super.onStop();
        sm.unregisterListener(se);
    }

    private void flashOn() {
        camera = Camera.open();
        Camera.Parameters p = camera.getParameters();
        p.setFlashMode(Camera

        .Parameters.FLASH_MODE_TORCH);
        camera.setParameters(p);
        camera.startPreview();
        Log.e("error", "on");
    }

    private void flashOff() {
        if (camera != null) {
            camera.stopPreview();
            camera.release();
            camera = null;
            Log.e("error", "Off");
        }
    }
}

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">


    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/data"
        android:paddingBottom="20dp"
        android:textSize="20sp"/>

</LinearLayout>

AndroidManifest.xml
<?xml version="1.0" encoding="utf-8"?>
<manifest 
    xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.secondapp">
    
    <uses-permission-sdk-23 
    android:name="android.permission.CAMERA" />

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category 
                android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>