android - How do you set the size and position of a ViewGroup that is inside a RelativeLayout? (All Java, no XML) -

i've been trying understand how draw graphics on android using hierarchy of custom views, custom viewgroups, , relativelayouts. i'm having hard time figuring out how have parents tell children position , @ size. think working when custom viewgroup tells children size, can't figure out how have relativelayout tell viewgroup children size , position be. right now, following code draws circle in top , center of screen. (this android 3.0 on xoom). size of circle 295x295, i'm assuming somehow default size , position of layout? can give me code needed programatically pick size , location of viewgroup contains view contains circle? edges of circle on 4 sides getting trimmed off so, know relativelayout cutting off rest of viewgroup printing. if have viewgroup measure() view @ smaller size, print @ size in left corner of same rectangle in top center of screen.

my activity's oncreate:

 public void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     customviewgroup custvg = new customviewgroup(this);     relativelayout rel = new relativelayout(getapplicationcontext());     rel.setlayoutparams(new layoutparams(layoutparams.fill_parent, layoutparams.fill_parent));      rel.addview(custvg);      relativelayout.layoutparams params2 = new relativelayout.layoutparams(layoutparams.wrap_content,                       layoutparams.wrap_content);       params2.addrule(relativelayout.align_parent_right);        rel.addview(new customviewgroup(getapplicationcontext()),1,             new viewgroup.layoutparams(layoutparams.match_parent,layoutparams.match_parent));      setcontentview(rel);  } 

my custom made viewgroup:

customview cust; int _height; int _width;  public customviewgroup(context context) {     super(context);     cust = new customview(context);      canvas canvas = new canvas();      this.addview(cust,new relativelayout.layoutparams(layoutparams.match_parent, layoutparams.match_parent));  }  @override  public void ondraw(canvas canvas){     this.drawchild(canvas,cust,0); }     @override protected void onlayout(boolean arg0, int arg1, int arg2, int arg3, int arg4) {      cust.layout(this.getleft(), this.gettop(), this.getright(), this.getbottom()); }  @override protected void onmeasure(int widthmeasurespec, int heightmeasurespec){      //measure child     this.measurechild(cust,widthmeasurespec, heightmeasurespec);      _height = view.measurespec.getsize(heightmeasurespec);     _width = view.measurespec.getsize(widthmeasurespec);     setmeasureddimension(_height, _width); } 

my custom view

public customview(context context){     super(context);  }  @override public void ondraw(canvas canvas) {      float noteradius = _width/2;      paint paint = new paint();     paint.setantialias(true);     paint.setcolor(color.yellow);     paint.setstyle(paint.style.stroke);     float strokewidth = paint.getstrokewidth();     paint.setstrokewidth(strokewidth);      canvas.drawcircle(_height/2, _width/2, noteradius, paint);  }     @override     protected void onmeasure(int widthmeasurespec, int heightmeasurespec) {          _height = view.measurespec.getsize(heightmeasurespec);         _width = view.measurespec.getsize(widthmeasurespec);         log.i("customview onmeasure","width: " + _width + " height: " + _height);          setmeasureddimension(_height, _width);     } 

sorry long. thanks!

okay - figured out problem. 1) missing <uses-sdk android:minsdkversion="11" /> line in manifest wasn't filling screen of xoom.

2) didn't realize don't have use match_parent or wrap_content layout params. instance following create circle of size 500x500 , put in bottom left of screen (it goes off screen expected).

relativelayout.layoutparams params2 = new relativelayout.layoutparams(500,                       500);       params2.leftmargin = 0;     params2.topmargin = 200; rel.addview(new customviewgroup(this),1,params2);