Flashlight

Summary

The base of this project is LED provided along with the Camera in a typical Android smart phone. After seeing that Play Store has a number of apps that ask for unnecessary permissions, I decided to create an app that toggles the LED without asking for any type of permission. This app also implements a service that detects when the device is shook (used to toggle the flashlight).

As of June 24th of 2018, Flashlight is licensed under Apache License version 2.0.

Downloads

Latest apk: Flashlight.apk

Source Code (zip): Flashlight.zip

Source Code (tar.gz): Flashlight.tar.gz

Contributors

• Code Optimization : RamusisTrenksmas
• Logo and Images : Dee-y

Code

The majority of the code is written in Java and is simple. For detecting shake motion: Declare global variables:

    SensorManager sensorManager = null;
    public static final float SHAKE_THRESHOLD = 10.25f; // How hard should user shake to invoke the service
    public static final int MIN_TIME_BETWEEN_SHAKES = 1000;
    private long lastShakeTime = 0;
    private boolean isFlashlightOn = false;

Initialize sensorManager:

    sensorManager = (SensorManager) getSystemService(SENSOR_SERVICE);
    if (sensorManager != null) {
        Sensor accelerometer = sensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
        sensorManager.registerListener((SensorEventListener) this, accelerometer, SensorManager.SENSOR_DELAY_NORMAL);
    }

Make class implement SensorEventListener interface and override it's onSensorChanged method:

      @Override
    public void onSensorChanged(SensorEvent event) {
        if (event.sensor.getType() == Sensor.TYPE_ACCELEROMETER) {
            long curTime = System.currentTimeMillis();
            if ((curTime - lastShakeTime) > MIN_TIME_BETWEEN_SHAKES) {

                float x = event.values[0];
                float y = event.values[1];
                float z = event.values[2];

                double acceleration = Math.sqrt(Math.pow(x, 2) +
                        Math.pow(y, 2) +
                        Math.pow(z, 2)) - SensorManager.GRAVITY_EARTH;

                if (acceleration > SHAKE_THRESHOLD) {
                    lastShakeTime = curTime;
                    if (!isFlashlightOn) {
                        torchToggle("on");
                        isFlashlightOn = true;
                    }
                    else {
                        torchToggle("off");
                        isFlashlightOn = false;
                    }
                }
            }
        }

Create a function torchToggle(String command):

    private void torchToggle(String command) {
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            CameraManager camManager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
            String cameraId = null; // Usually back camera is at 0 position.
            try {
                if (camManager != null) {
                    cameraId = camManager.getCameraIdList()[0];
                }
                if (camManager != null) {
                    if (command.equals("on")) {
                        camManager.setTorchMode(cameraId, true);   // Turn ON
                        isFlashlightOn = true;
                    } else {
                        camManager.setTorchMode(cameraId, false);  // Turn OFF
                        isFlashlightOn = false;
                    }
                }
            } catch (CameraAccessException e) {
                e.getMessage();
            }
        }
    }

Contributing

Any help, including feedback, is highly appriciated. I have just started out with Android and I’m relatively new to app development.

1. Fork it!
2. Create your feature branch: git checkout -b new-branch
3. Commit your changes: git commit -am 'Make a valuable addition'
4. Push to the branch: git push origin new-feature
5. Submit a pull request :D

Next Step

Once staretd, an app can never be completely finished.

1. Revamp the project and make it better.