Search code examples
androidkotlinlet

Let block not working, giving "Only safe (?.)..." error

My parent variable is nullable, and haves a getWidth function. I want to call getWidth only if parent is not null, so I did this let function:

return parent.let {
    it.getWidth() * (perWidth / 100.0f)
} ?: run{
    App.realWidth.toFloat()
}

Also, if is null, I want to call App.realWidth.toFloat(), so I added it in a ?: run which I read is like doing an else in a let function.

The problem is that it is giving me this error on it.getWidth()

Only safe (?.) or non-null asserted (!!.) calls are allowed on a nullable receiver of type ParentInterface?

I don't understand why, because it can't be null, as it is inside a let block.

How can I solve this?

Solution

  • You should write it as

    return parent?.let {

    Otherwise it still comes in the let block when it's null, with it being null