Change the margin of a constraint layout programmatically

Question

I have created constraint layout which is use by many view but in a specific one, I need to modify the margin but I can't find the best way to do it.

the code is:

class BundleItemView @JvmOverloads constructor(
    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : ConstraintLayout(context, attrs, defStyleAttr) {

  init {
    View.inflate(context, R.layout.item_product, this)
  }

  fun setProduct(product: Product) {
    /* change margin to 0 for this constraint layout */
    item_store_product_layout.leftPadding = dip(0)
    product_image.setImageURI(ImageUtil.getCellImageWithFallback(product))
    product_name.text = product.completeTitle
    product_sub_name_1.text = product.prettySizeString
    product_add_button.text = context.getString(R.string.view_details)

    product_regular_price_label.visibility = View.GONE
    product_regular_price_value.visibility = View.GONE
    product_price.setPrice(product.originalPrice)

    product_add_button.onClick {
      Toast.makeText(context, product.completeTitle, Toast.LENGTH_SHORT).show()
    }
  }

}

So When I infalte the item_product.xml, I would like to modify the layout. I already changing the left padding using the command:

    item_store_product_layout.leftPadding = dip(0)

but it's not working for margin.

Any idea how to change the margin of the constraint layout programmatically ?

Thanks

Answer 1

Margins are associated with a View but belong to the ViewGroup which, is in your case, is a ConstraintLayout. Make the margin changes in the ConstraintLayout.LayoutParams

// view is the view to change margins for
val lp = view.layoutParams as ConstraintLayout.LayoutParams
lp.leftMargin = 200 // change to 200px
lp.topMargin = 200
lp.rightMargin = 200
lp.bottomMargin = 200
view.requestLayout() // May or may not be needed depending upon where the code is placed.

If you are changing connections, margins can also be set in a ConstraintLayout using a ConstraintSet.

val cs = ConstraintSet()
cs.clone(layout) // layout is the ConstraintLayout
cs.connect(
    R.id.textView,
    ConstraintSet.START,
    ConstraintSet.PARENT_ID,
    ConstraintSet.START,
    200 // Start margins is now 200px
)
cs.applyTo(layout)

You are setting the visibility of some widgets to View.GONE so maybe you can make use of Gone Margins.