@mark4jets thank you for your answer.
I have seen your link but like you, i'm not a developer.
I just need to unlock an easy action to launch the action "shoot a photo" in any app that permit to take a photo with volume button for example.
I know that there is a way to do it but i don't know which is the best one without write code.
I make an example, Flic app permits to read a sentence and my native camera app permits to shoot a photo with a voice command. So now, i have create the action to say "capture". So i open my camera app, i set every parameters and next with flic button i shoot the photo reading the sentence "capture".
It's absolutely an ugly way to take a photo ahahah that's why i would like to improve this function.
I think that simulate physical buttons could solve this problem in a better way.
Or maybe these solutions
https://developer.android.com/training/camera/photobasics.html
https://coderwall.com/p/3-tgjg/take-a-photo-via-adb
Or similar to this one
https://stackoverflow.com/questions/6061421/how-to-disable-search-key-and-camera-key-while-displaying-menu
I mean, an intent with this action
Android.intent.action.VOICE_COMMAND
it works
This one
android.intent.action.CAMERA_BUTTON
Doesn't work
What do you think?