Develop Reference

How to automatically turn on flashlight for video recording when the scene is dark?

My app shows a preview and video recording starts with a button press.
What I'm trying to achieve is to automatically turn on flashlight (torch mode) as soon as the video recording starts.
However I couldn't find a way to do so. On Camera2 API we can use FLASH_MODE_AUTO which will use the flashlight when capturing photo when the scene is dark, but that doesn't work for video recording.
There's this FLASH_MODE_TORCH which I could use to turn on the flashlight just like I wanted, but there isn't a FLASH_MODE_TORCH_AUTO to automatically do so when the scene is dark..
There were some answers that uses Ambient light sensor (Sensor.TYPE_LIGHT) of the device to determine whether we are in a dark scene, however that uses the front ambient light sensor instead of the camera itself I think. This is not ideal as the ambient light can be low but the rear camera is able to adjust exposure level to achieve good enough image quality without using flash. So ideally if the camera says 'flash is required' then only the app activates FLASH_MODE_TORCH.
Since the app shows a preview the device already know whether flash is needed before the button press, is there a way to determine whether flash is required during preview?

Please try the below method where you need you can use it
below is for Camera API
public void switchFlashOnMode() {
Camera.Parameters p = getCamera().getParameters();
try {
//p.setFlashMode(Camera.Parameters.FLASH_MODE_TORCH);
p.setFlashMode(Parameters.FLASH_MODE_AUTO);
getCamera().setParameters(p);
getCamera().startPreview();
isFlashTorch = true;
}catch (Exception e){
e.printStackTrace();
}
}
public void switchFlashOffMode() {
Camera.Parameters p = getCamera().getParameters();
try {
p.setFlashMode(Camera.Parameters.FLASH_MODE_OFF);
getCamera().setParameters(p);
Thread.sleep(200);
getCamera().stopPreview();
isFlashTorch = false;
}catch (Exception e){
e.printStackTrace();
}
}
below is for Camera2 API
void switchFlashMode() {
if (!flashSupport) return;
try {
if (isFlashTorch) {
isFlashTorch = false;
requestBuilder.set(CaptureRequest.FLASH_MODE, CameraMetadata.FLASH_MODE_OFF);
} else {
isFlashTorch = true;
//requestBuilder.set(CaptureRequest.FLASH_MODE,CameraMetadata.FLASH_MODE_TORCH);
requestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH);
}
cameraCaptureSession.setRepeatingRequest(requestBuilder.build(), null, null);
} catch (Exception e) {
e.printStackTrace();
}
}
hope it will help you

Finally figured this out, gpuser's answer used the right flag but it is not complete - still need to code the callback and turn on the torchlight when needed.
I also found that for video recording, we still use the same Camera2 API init and configuration steps, just that some of the callbacks will be fired multiple times, so I added a flag to perform the flash detection only once.
1)After camera started capturing, run this code
performAutoTorchDetectionOnce = true; // set this flag first, will be used later
captureRequestBuilder = camera.createCaptureRequest(CameraDevice.TEMPLATE_RECORD);
captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON_AUTO_FLASH); // CONTROL_AE_MODE_ON_AUTO_FLASH is important here, to enable flash detection
captureSession.setRepeatingRequest(captureRequestBuilder.build(), captureCallback, null);
2)And this is my captureCallback implementation, change it depending on your needs. The gist of it is that eventually the camera capture will fall into one of the two states, CONTROL_AE_STATE_CONVERGED or CONTROL_AE_STATE_FLASH_REQUIRED. These two states mean that auto exposure algorithm has finished running, if it is converged means no flash is needed whereas flash_required will mean that we have to turn on flash. In the latter we will then need to manually turn on the flash in the next step.
private CameraCaptureSession.CaptureCallback captureCallback =
new CameraCaptureSession.CaptureCallback() {
#Override
public void onCaptureStarted(CameraCaptureSession session, CaptureRequest request,
long timestamp, long frameNumber) {
super.onCaptureStarted(session, request, timestamp, frameNumber);
}
#Override
public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
super.onCaptureCompleted(session, request, result);
Integer aeState = result.get(CaptureResult.CONTROL_AE_STATE);
if (aeState != null) {
if (performAutoTorchDetectionOnce) {
if (aeState == CameraMetadata.CONTROL_AE_STATE_CONVERGED // CONTROL_AE_STATE_CONVERGED means Auto-exposure has finished
|| aeState == CameraMetadata.CONTROL_AE_STATE_FLASH_REQUIRED) { // CONTROL_AE_STATE_FLASH_REQUIRED means Auto-exposure has finished, but flash is required
performAutoTorchDetectionOnce = false;
enableTorch(aeState == CameraMetadata.CONTROL_AE_STATE_FLASH_REQUIRED);
}
}
}
}
};
3)Here's the enableTorch implementation. I tried leaving CONTROL_AE_MODE as CONTROL_AE_MODE_ON_AUTO_FLASH but it didn't work, torch light does not turn on, so I have to change it to CONTROL_AE_MODE_ON.
public synchronized void enableTorch(boolean enable) {
Timber.d("enableTorch(" + enable + ") called");
try {
if (isCaptureStarted()) {
if (enable) {
captureRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_TORCH);
} else {
captureRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
}
captureRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);
captureSession.setRepeatingRequest(captureRequestBuilder.build(), null, null);
}
} catch (CameraAccessException e) {
Timber.e(e, "enableTorch(" + enable + ") failed: ");
}
}

hasSystemFeature(PackageManager.FEATURE_CAMERA) returns true for device with no camera

I have a application which uses camera functionality in it but part of its functionality can also run without camera feature. SO I have put this in my manifest.
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" android:required="false"/>
and in my code I check whether the device has camera or not using this
final boolean deviceHasCameraFlag = pm.hasSystemFeature(PackageManager.FEATURE_CAMERA);
Now I am testing my code on a tablet which runs Android 4.0(ICS) and has no camera. But still I get True value for the deviceHasCameraFlag. Is this weird or am I missing something.
I tried different things and even tried the same thing on Bluetooth feature as Tablet even doesn't have Bluetooth feature. It works fine for Bluetooth but gives me true for camera.

Which device is it? The answer you get is a bug, and 4.0 is very old nowadays. Many tablets that still run this version were not crafted correctly, both hardware and software featuring multiple problems.
Regardless, you should always be prepared to handle failure on Camera.open() or Camera.open(0): for example, in some cases other software on your device will not release the camera gracefully.
So, in your case you have a false positive, you try to open the camera, it fails, and you continue as if there is no camera on the device, even if PackageManager thinks that PackageManager.FEATURE_CAMERA is availabe.

Though I have accepted Alex's answer I still want to put this one collectively as what can be the best solution in such condition.
What I found was in case of some low standard android devices
pm.hasSystemFeature(PackageManager.FEATURE_CAMERA)
returns true even if camera doesn't exist and that seems to be a device bug for me which in unchecked.
So whenever there is scenario that you need to check if camera exists for a device or not best practice is something that I am putting below (best practice as per my knowledge if there is something more interesting and best solution that this you are welcome to put it here on this post)
int numberOfCameras = Camera.getNumberOfCameras();
context = this;
PackageManager pm = context.getPackageManager();
final boolean deviceHasCameraFlag = pm.hasSystemFeature(PackageManager.FEATURE_CAMERA);
if( !deviceHasCameraFlag || numberOfCameras==0 )
{
Log.e(TAG, "Device has no camera" + numberOfCameras);
Toast.makeText(getApplicationContext(), "Device has no camera", Toast.LENGTH_SHORT).show();
captureButton.setEnabled(false);
}
else
{
Log.e(TAG, "Device has camera" + deviceHasCameraFlag + numberOfCameras);
}
In this I am checking both number of cameras as well as device has camera feature Boolean , so in any case it would not fail my condition.

In my case I had this code:
public boolean hasCameraSupport() {
boolean hasSupport = false;
if(getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_ANY)) { //<- this constant caused problems
hasSupport = true;
}
return hasSupport;
}
and it kept returning false on a Genymotion device running Android 4.1.1 (API 16). Once I changed the constant PackageManager.FEATURE_CAMERA_ANY to PackageManager.FEATURE_CAMERA, my problems went away. I am guessing that not all devices/API levels support PackageManager.FEATURE_CAMERA_ANY.

I got it you will try this one definitely it will work....
import android.hardware.Camera;
int numCameras = Camera.getNumberOfCameras();
if (numCameras > 0) {
System.out.println("camera");
} else {
System.out.println("No Camera");
}

For CameraX, if the FEATURE_CAMERA_ANY method is still returning true when there is no Camera on device, you can add the below method. So whether FEATURE_CAMERA_ANY returns true or false when CameraX is getting initialized, Below method will make sure to do what you want if a camera is actually not available on device.
private CameraSelector cameraSelector;
private ProcessCameraProvider cameraAvailableCheck;
private ListenableFuture<ProcessCameraProvider> cameraAvailableCheckFuture;
private void checkIfAnyCameraExist()
{
cameraAvailableCheckFuture = ProcessCameraProvider.getInstance(context);
cameraAvailableCheckFuture.addListener(new Runnable() {
#Override
public void run() {
try {
cameraAvailableCheck = cameraAvailableCheckFuture.get();
if ((cameraAvailableCheck.hasCamera(cameraSelector.DEFAULT_BACK_CAMERA) || cameraAvailableCheck.hasCamera(cameraSelector.DEFAULT_FRONT_CAMERA) ))
{
//Do what you want if at least back OR front camera exist
}
else
{
//Do what you want if any camera does not exist
}
}
catch (ExecutionException | InterruptedException | CameraInfoUnavailableException e)
{
// No errors need to be handled for this Future.
// This should never be reached.
}
}
}, ContextCompat.getMainExecutor(this));
}

Please try this code:
private boolean isDeviceSupportCamera() {
if (getApplicationContext().getPackageManager().hasSystemFeature(
PackageManager.FEATURE_CAMERA)) {
// this device has a camera
return true;
} else {
// no camera on this device
return false;
}
}
Still it does't work then please let me know

Switching cameras for video on the fly on android

I know it is possible as the camera app that comes with my droid phone does it, but for the life of me, I don't seem to be able to switch cameras on the fly either for video or a standard camera (which leads me to suspect I'm not doing it right!)
Currently, I have an event for the button
btnSwitchCamera.Click += new EventHandler(btnSwitchCamera_Click);
prior to that, I check for the number of cameras - if there is only one camera, the event is not enabled.
The switch code looks like this
private void btnSwitchCamera_Click(object s, EventArgs e)
{
if (isBackCamera == false)
{
try
{
RunOnUiThread(delegate
{
camera.Release();
camera = Android.Hardware.Camera.Open(1);
});
}
catch (Java.Lang.RuntimeException)
{
alertMsg(context, Application.Context.Resources.GetString(Resource.String.videoErrorTitle),
Application.Context.Resources.GetString(Resource.String.videoFailToConnect));
return;
}
isBackCamera = true;
}
else
{
try
{
RunOnUiThread(delegate
{
camera.Release();
camera = Android.Hardware.Camera.Open(0);
});
}
catch (Java.Lang.RuntimeException)
{
alertMsg(context, Application.Context.Resources.GetString(Resource.String.videoErrorTitle),
Application.Context.Resources.GetString(Resource.String.videoFailToConnect));
return;
}
isBackCamera = false;
}
}
If I click the button, the app dies claiming that I cannot connect to the service.
The video record code is nothing special - it's a bog standard set the surface, do the holder, and start/stop recording.
Am I doing this right? From the docs, I need to release the camera then open the camera with the appropriate camera number (Android.Hardware.Camera.NumberOfCameras - 1)
The manifest is correctly set.
Thanks
Paul

Runtime Error: failed to connect to camera service in android

I wanted to make use of the zxing library to detect qrcodes in my app. But for the apps viewing purpose, i had to change the custom display orientation to portrait. Hence i had to integrate the whole zxing library into my app and addded camera.setDisplayOrientation(90) to the openDriver() method.
After doing this, the program works, but I get "Runtime exceptions : Fail to connect to camera service" randomly.
public void openDriver(SurfaceHolder holder) throws IOException {
if (camera == null) {
camera = Camera.open();
camera.setDisplayOrientation(90);
if (camera == null) {
throw new IOException();
}
}
camera.setPreviewDisplay(holder);
if (!initialized) {
initialized = true;
configManager.initFromCameraParameters(camera);
}
configManager.setDesiredCameraParameters(camera);
SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(context);
reverseImage = prefs.getBoolean(PreferencesActivity.KEY_REVERSE_IMAGE, false);
if (prefs.getBoolean(PreferencesActivity.KEY_FRONT_LIGHT, false)) {
FlashlightManager.enableFlashlight();
}
}
public void closeDriver() {
if (camera != null) {
FlashlightManager.disableFlashlight();
camera.release();
camera = null;
framingRect = null;
framingRectInPreview = null;
}
}
/**
* Asks the camera hardware to begin drawing preview frames to the screen.
*/
public void startPreview() {
if (camera != null && !previewing) {
camera.startPreview();
previewing = true;
}
}
/**
* Tells the camera to stop drawing preview frames.
*/
public void stopPreview() {
if (camera != null && previewing) {
if (!useOneShotPreviewCallback) {
camera.setPreviewCallback(null);
}
camera.stopPreview();
previewCallback.setHandler(null, 0);
autoFocusCallback.setHandler(null, 0);
previewing = false;
}
}

I doubt that the orientation change is causing that. I have found you will get that error whenever an activity stops but fails to call Camera.release in their onPause. The result is that the next time you try to do Camera.open you get that runtime error since the driver still considers it open regardless of the app/activity that opened it being gone.
You can easily get this to happen while debugging/testing stuff when something throws an exception and brings the activity down. You need to be very diligent about catching all exceptions and being sure to release the camera before finishing the activity.
BTW, are you finding you need to power cycle the device in order to be able to open the camera again?

Camera.Parameters.FLASH_MODE_TORCH replacement for Android 2.1

I am trying to write an app that requires the LED flash to go into torch mode. The problem is, Android 2.1 does not support this mode and therefore I cannot support the platform yet. Wouldn't be an issue, but I am writing it for my fiance and her Epic 4G only has 2.1 right now. I found some code samples that use some undocumented API calls and therefore work on the Motorola Droid and such, but they do not work on the Epic. Does anyone have some suggestions on where to look to find code that should help me get this working?

I'm finding that torch mode is generally working fine on 2.1 but I had the same problem with the Samsung Epic and found a hack around it.
Looking at the params returned by Camera.getParameters() when run on the Samsung Epic, I noticed that the flash-modes it claims to support are: flash-mode-values=off,on,auto;
torch-mode is not listed, implying it's not supported.
However, I found that this model would still accept that mode and WOULD turn the LED on! The bad news was that when later setting the flash-mode back to auto or off left the LED still lit! It will not turn off until you call Camera.release().
I guess that's why Samsung dont include it in the list of supported!?!
So...the method I use to toggle torch in a CameraHelper class is...
/***
* Attempts to set camera flash torch/flashlight mode on/off
* #param isOn true = on, false = off
* #return boolean whether or not we were able to set it
*/
public boolean setFlashlight(boolean isOn)
{
if (mCamera == null)
{
return false;
}
Camera.Parameters params = mCamera.getParameters();
String value;
if (isOn) // we are being ask to turn it on
{
value = Camera.Parameters.FLASH_MODE_TORCH;
}
else // we are being asked to turn it off
{
value = Camera.Parameters.FLASH_MODE_AUTO;
}
try{
params.setFlashMode(value);
mCamera.setParameters(params);
String nowMode = mCamera.getParameters().getFlashMode();
if (isOn && nowMode.equals(Camera.Parameters.FLASH_MODE_TORCH))
{
return true;
}
if (! isOn && nowMode.equals(Camera.Parameters.FLASH_MODE_AUTO))
{
return true;
}
return false;
}
catch (Exception ex)
{
MyLog.e(mLOG_TAG, this.getClass().getSimpleName() + " error setting flash mode to: "+ value + " " + ex.toString());
}
}
The activities that use this call it as follows...
private void toggleFlashLight()
{
mIsFlashlightOn = ! mIsFlashlightOn;
/**
* hack to fix an issue where the Samsung Galaxy will turn torch on,
* even though it says it doesnt support torch mode,
* but then will NOT turn it off via this param.
*/
if (! mIsFlashlightOn && Build.MANUFACTURER.equalsIgnoreCase("Samsung"))
{
this.releaseCameraResources();
this.initCamera();
}
else
{
boolean result = mCamHelper.setFlashlight(mIsFlashlightOn);
if (! result)
{
alertFlashlightNotSupported();
}
}
}
The magic that makes this work in releaseCameraResources() is that it calls Camera.release()....and then I have to reinitialize all my camera stuff for Samsung devices.
Not pretty but seems to be working for plenty of users.
Note that I do have a report of torch mode not working at all with this code on Nexus one but have been able to dig into it. It definitely works on HTC EVO and Samsung Epic.
Hope this helps.

In my case for Samsung devices I needed to set focus mode to infinity and it started to work
params.setFocusMode(Camera.Parameters.FOCUS_MODE_INFINITY);
mCamera.setParameters(params);
mCamera.startPreview();