Is there any way to release a camera from different activity after acquiring it from a different activity.?

Question

I am developing a flashlight App in which there is a normal flashlight in one activity and strobe light in one activity. Now I am acquiring the camera in onCreate of Flashlight activity. But when I am oving to strobe activity, i need to release the camera acquired by FlashLight activity. I dont want to release the camera in onPause of FlashLight activity because that would stop the camera even if user presses the home button. I want to release the camera only when user goes to strobe activity or else he exits the app by back button. Also I want to reacquire the camera if the user is coming back to flashlight activity from strobe activity. Is their anyway to do this.?

Answer 1

Other answers have told you not to do this and why. But to answer your question:

Keep a reference to the Camera instance in a static member variable, preferably in a separate class, like this:

public class Globals {
    public static Camera myCamera;
}

This variable is available to all of your activities as Globals.myCamera.

Put the instance of Camera that you get from calling Camera.open() into Globals.myCamera. This will be available to both activities. When you are ready to release the camera, call Globals.myCamera.release() and then set Globals.myCamera to null to indicate that you no longer have control of the camera.

Answer 2

I want to release the camera only when user goes to strobe activity or else he exits the app by back button.

If you do not release the camera resources as soon as possible, the user will be unable to use camera from any other application. For example, if user of your app would press a home button, camera object would be left locked by your app. That would result in troublesome behaviour: for example, user failing to start a Camera application.

As official docs suggest:

Important: Call release() to release the camera for use by other applications. Applications should release the camera immediately in onPause()

I want to release the camera only when user goes to strobe activity or else he exits the app by back button

If you do not release camera resources manually, they will not be released simply be pressing back button and "exiting" your app.

Also I want to reacquire the camera if the user is coming back to flashlight activity from strobe activity. Is their anyway to do this.?

Just connect to your camera in onResume(), and release resources in onPause().