Android extended LinearLayout height matches parent, but children do not -

i extending linearlayout matching parents height , width. inside linearlayout, inflating view set match parent height , width well. inflated views width matches parent, inflated views height not.

i have tested on 2 devices, 1 running kitkat (api 19), in case problem occurs, , 1 running marshmallow (api 23), in case problem not occur.

this extended linearlayout:

public class messagebackground extends linearlayout {      public messagebackground(context context) {         this(context, null);     }      public messagebackground(final context context, attributeset attrs) {         super(context, attrs);         layoutinflater inflater = (layoutinflater) context.getsystemservice(context.layout_inflater_service);         inflater.inflate(r.layout.message_background_layout, this, true);         this.setbackgroundcolor(context.getresources().getcolor(r.color.red));     }  } 

this inflated xml layout:

<?xml version="1.0" encoding="utf-8"?> <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:minheight="20dp"     android:background="#0000ff"> </relativelayout> 

these different results on kitkat , marshmallow:

i have tried several variations try , xml layout match height of linearlayout on kitkat, can't seem find way work. suggestions or reasons why behaviour different helpful.