int addLayer(ChildDrawable layer){
  final LayerState st=mLayerState;
  final int N=st.mChildren != null ? st.mChildren.length : 0;
  final int i=st.mNum;
  if (i >= N) {
    final ChildDrawable[] nu=new ChildDrawable[N + 10];
    if (i > 0) {
      System.arraycopy(st.mChildren,0,nu,0,i);
    }
    st.mChildren=nu;
  }
  st.mChildren[i]=layer;
  st.mNum++;
  st.invalidateCache();
  return i;
}

int addLayer ( ChildDrawable layer ) { final LayerState st = mLayerState ; final int N = st . mChildren != null ? st . mChildren . length : 0 ; final int i = st . mNum ; if ( i >= N ) { final ChildDrawable [ ] nu = new ChildDrawable [ N + 10 ] ; if ( i > 0 ) { System . arraycopy ( st . mChildren , 0 , nu , 0 , i ) ; } st . mChildren = nu ; } st . mChildren [ i ] = layer ; st . mNum ++ ; st . invalidateCache ( ) ; return i ; }
adds a new layer at the end of list of layers and returns its index .
