Get Current Temperature CPU android

Question

I made code to read cpu temperature in android. But there is an error like this

java.io.FileNotFoundException: /sys/devices/virtual/thermal/thermal_zone0/temp: open failed: EACCES (Permission denied)

private double getCurrentCPUTemperature() throws IOException, InterruptedException {
    ArrayList <Float> suhu = new ArrayList<>();
    Process process;
    String line;
    BufferedReader reader;
    RandomAccessFile reader1;
    for (int i = 0; i <= 30 ; i ++ ) {
        process = Runtime.getRuntime().exec("cat /sys/devices/virtual/thermal/thermal_zone" + i + "/temp");
        process.waitFor();
        reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
        line = reader.readLine();
        System.out.println("Line = " + line);
        if(line != null){
            Float temp = Float.parseFloat(line);
            suhu.add(temp);
        }
        if(line == null){
            reader1 = new RandomAccessFile("/sys/devices/virtual/thermal/thermal_zone" + i +"/temp", "r");
            line = reader.readLine();
            if (line != null){
                System.out.println(line + " RAM");
                Float temp1 = Float.parseFloat(line);
                suhu.add(temp1);
            }
        }
        if (i == 30){
            reader.close();
            process.destroy();
        }
    }
    double temp = 0.0;
    for (int i = 0; i < suhu.size() ; i++){
        if (suhu.get(i) > temp){
            temp = (double) suhu.get(i);
        }
    }
    System.out.println(suhu);
    return temp;
}

i have make request permission for read and write external storage. Manifest :

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.example.gpc1">
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

<application
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:roundIcon="@mipmap/ic_launcher_round"

And in activity

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sensor);
    BottomNavigationView bottomNavigationView = findViewById(R.id.bottom_navigation);
    bottomNavigationView.setSelectedItemId(R.id.page_2);
    bottomNavigationView.setOnNavigationItemSelectedListener(this);

    requestPermissionStorage();

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(requestCode == STORAGE_PERMISSION_CODE){
        if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
            requestPermissionStorage();
        } else {
            Toast.makeText(this, "Permission DENIED", Toast.LENGTH_SHORT).show();
        }
    }
}

private void requestPermissionStorage() {
    if (ActivityCompat.checkSelfPermission(this,
            Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
    }
    else {
        System.out.println("Request External Storage");
    }
}

Thanks and i appreciate your help

Answer 1

I too couldn't get hold of TYPE_AMBIENT_TEMPERATURE with my phones, so instead decided to monitor the battery temperature:

var batteryReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        var temperature = intent.getIntExtra(BatteryManager.EXTRA_TEMPERATURE, 0);
        var celsius = temperature / 10.0f; // Battery temperature in Celsius
        Log.i(TAG, String.format("temperature: %f", celsius));
    }
};

registerReceiver(batteryReceiver, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));

Works the way you would expect. Close enough for my use case.

Hope that helps, cheers

Answer 2

You can use TYPE_AMBIENT_TEMPERATURE for battery or CPU temperature. TYPE_TEMPERATURE is the depcrecated constant.

The modified version of code available at documentation should be like this:

import android.app.Activity;
import android.hardware.Sensor;
import android.hardware.SensorEvent;
import android.hardware.SensorEventListener;
import android.hardware.SensorManager;

public class TempSensorActivity extends Activity, implements SensorEventListener {
 private final SensorManager mSensorManager;
 private final Sensor mTempSensor;

 public TempSensorActivity() {
     mSensorManager = (SensorManager)getSystemService(SENSOR_SERVICE);
     mTempSensor = mSensorManager.getDefaultSensor(Sensor.TYPE_AMBIENT_TEMPERATURE);
 }

 protected void onResume() {
     super.onResume();
     mSensorManager.registerListener(this, mTempSensor, SensorManager.SENSOR_DELAY_NORMAL);
 }

 protected void onPause() {
     super.onPause();
     mSensorManager.unregisterListener(this);
 }

 public void onAccuracyChanged(Sensor sensor, int accuracy) {
 }

 public void onSensorChanged(SensorEvent event) {
 }
}

Look at sensor documentation for more