How to use Camera Lib QML to turn on/off Flash light of Android devices

[Drakel]

Hello all, I have a question about how to use Camera Lib Qml, I 've written demo code to turn on/ off flash light of Android device but it hasn't run, I dont know why. My code below :

Button {
        id: btn
        property bool isClicked: false
        anchors.centerIn: parent
        text: "Click"

        onClicked: {
            isClicked = !isClicked
            if (isClicked) {
                camera.FlashOn
            } else {
                camera.FlashOff
            }
        }
}

 Camera {
            id: camera
            flash.mode: Camera.FlashTorch
        }
    

I've tried Camera.FlashVideoLight, it run but i can't turn on/off with button onClicked, Can you tell me how to use it ?
Thank you

[raven-worx]

@Drakel
did you specify (Android API <23) in AndroidManifest.xml or request (Android API >= 26) the android.permission.CAMERA permission?

[Drakel]

I used QT version 5.12.2 for windows with JDK 8.0, SDK 26.1.1 and NDK 19.2, it It automatically generates AndroidManifest.xml for me, I see the content of file has <uses-permission android:name="android.permission.CAMERA" /> , I think Qt has added permission. My devices test use android 4.4.2 and 9.0. Can you help to fix that
Thank you in advance

[raven-worx]

@Drakel
as i provided the link.
You need to request the permission at runtime (at least once).

Also see this, you will see in the Android settings menu if the app has the permission or not.