How to detect button release after button press in Android Jetpack Compose?-CodePudding

I find listeners for onClick and onLongClick and even onPress but there is no event/listener for something like buttonDown and buttonUp, or onPress and onRelease.

Am I missing something? My current use case is that when a user presses a button I increment a count and when the user releases it I decrease the count. But in general I want something to start happening as soon as the user presses the button and stop when the user releases it. (For a real life example, see how Facebook Messenger records a video, you keep the button pressed to start and it stops when you release it.

I am using Jetpack Compose on Android. TIA.

CodePudding user response：

I think you use Touch Listener on button , its easily detect button touch or untouch example

override fun onTouchEvent(e: MotionEvent): Boolean {
val x: Float = e.x
val y: Float = e.y

when (e.action) {
    MotionEvent.ACTION_MOVE -> {

        var dx: Float = x - previousX
        var dy: Float = y - previousY

        // reverse direction of rotation above the mid-line
        if (y > height / 2) {
            dx *= -1
        }

        // reverse direction of rotation to left of the mid-line
        if (x < width / 2) {
            dy *= -1
        }

        renderer.angle  = (dx   dy) * TOUCH_SCALE_FACTOR
        requestRender()
    }
}

previousX = x
previousY = y
return true

}

More info of Touch Listener in this link Android Touch Listener

CodePudding user response：

Use .pointerInput modifier:

.pointerInput(Unit) {
            forEachGesture {
                awaitPointerEventScope {
                    awaitFirstDown()
                    //onPress actions here
                    do {
                        val event = awaitPointerEvent()
                        //Track other pointer evenst, like Drag etc...
                    } while (event.changes.any { it.pressed })
                    //onRelease actions here
                }
            }
        }