Detect when the user stops pressing the button Jetpack Compose-CodePudding

I have a button and I want it to execute an action only while it is long pressed.

I am able to execute the action on the long press already, the problem is I do not know how to stop it once the user is no longer pressing down on the button.

1)How would one go about implementing something like this?

I am using Jetpack Compose on an Android App

CodePudding user response：

This code is not tested yet. But I believe this is what you are looking for:

Button(
  onClick = { /* TODO */ },
  modifier = Modifier.pointerInteropFilter {
    when(it.action) {
      MotionEvent.ACTION_DOWN -> {
        // User has pressed the button
      }
      MotionEvent.ACTION_UP -> {
        // User is no longer pressing the button
      }
      else -> false
    }
    true
  }
) {
  Text(text = "Click Me")
}

Don't forget about @ExperimentalPointerInput annotation.

CodePudding user response：

The Gestures API is probably what you are after.

You can use something like:

var longPressActive by remember { mutableStateOf(false) }

Modifier.pointerInput(Unit) {
  detectTapGestures(
    onLongPress = { longPressActive = true }
    onPress = {
      awaitRelease()
      longPressActive = false
    }
  )
}

You may also find other APIs regarding drag that match your requirements. May be worth expanding on what you are ultimately trying to accomplish.

CodePudding user response：

To do this, the Button has an argument interactionSource. It can be used as follows:

val interactionSource = remember { MutableInteractionSource() }
val isPressed by interactionSource.collectIsPressedAsState()

Button(
    onClick = { /*TODO*/ }
    interactionSource = interactionSource,
) {

}

If you need to perform some action until the button is released, you can use isPressed with LaunchedEffect:

if (isPressed) {
    LaunchedEffect(Unit) {
        // execute some action
    }
}

It is launched in a coroutine scope, which will be canceled as soon as isPressed becomes false.

An other option is using it with DisposableEffect:

if (isPressed) {
    DisposableEffect(Unit) {
        // do some action
        onDispose {
            // cancel some action
        }
    }
}