How to set Layoutparams height/width in dp value?

When you specify values programmatically in the LayoutParams, those values are expected to be pixels.

To convert between pixels and dp you have to multiply by the current density factor. That value is in the DisplayMetrics, that you can access from a Context:

float pixels =  dp * context.getResources().getDisplayMetrics().density;

So in your case you could do:

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float factor = holder.itemView.getContext().getResources().getDisplayMetrics().density;
params.width = (int)(item.getWidth() * factor);
params.height = (int)(item.getHeight() * factor);
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I believe you should be using a dp value defined in dimens along with getDimensionPixelSize. In a custom view, the Kotlin implementation would look like:

val layoutParams = layoutParams
val width = context.resources.getDimensionPixelSize(R.dimen.width_in_dp)
layoutParams.width = width