如何在带有Kotlin Anko布局的ConstraintLayout中使用GuideLine

Question

Question 1:

While I use guideline in ConstraintLayout, it doesn't work at all, the code below cannot set the orientation (Why there is no such property?) of guideline , which is useless:

constraintLayout {            
    guideline {
         //here, cannot set the orientation of guideline
    }
    //...
}

Even though the code below can set the guideline orientation, but it still has the same problem with the layout(I don't know whether the guideline is created or not):

constraintLayout {            
    constraintSet {
         create(ID_GUIDELINE, VERTICAL_GUIDELINE)
    }
    //...
}

So, what is the right way to use GuideLines in ConstraintLayout layout in Anko?

Question 2:

ConstraintLayou in another ConstraintLayout may have the unexpected behavior while use Fragment .

I use ConstraintLayout(named with A ) in Activity , and ConstraintLayout( B ) in Fragment , then add or replace the B into/with A , the result shows the width of B is always incorrect.

However, if there is a RecyclerView in B , and set the layoutParams of B as below:

layoutParams = ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT)

then it works correctly, without RecyclerView but only other widgets, like buttons/textviews/imageviews , it shows that the width of B is very narrow.

Of course I can change the layout A to a FrameLayout , but that is not what I want, so why and how to do that? Thanks for reply!

Also, I have opened the issue in Anko kotlin library here: https://github.com/Kotlin/anko/issues/579 , and code:

// A in Activity
constraintLayout {
    fitsSystemWindows = true
    id = A
}
supportFragmentManager.beginTransaction().replace(A, fragmentB).commit()
//supportFragmentManager.beginTransaction().add(A, fragmentB).commit()

// B in Fragment
constraintLayout {
    fitsSystemWindows = true
    layoutParams = ViewGroup.LayoutParams(MATCH_PARENT, MATCH_PARENT)
}

Answer 1

Question 1 try something like this:

    guideline {
      id = ID_GUIDELINE
    }.lparams(0, 0) {
      orientation = ConstraintLayout.LayoutParams.VERTICAL
      guideBegin = dip(80)
    }

Question 2 should be in a separate post with a good title so it's more likely to be answered and is more easily searchable by others.