android - Programmatically created "Circle Button" not drawing -

i have custom circlebutton class:

public class circlebutton extends imageview {  private  int radius; private  int x; private  int y;  public circlebutton(context context) {     super(context);     constructortask(); }  public circlebutton(context context, attributeset attrs) {     super(context, attrs);     constructortask(); }  public circlebutton(context context, attributeset attrs, int defstyleattr) {     super(context, attrs, defstyleattr);     constructortask(); }  public circlebutton(context context, attributeset attrs, int defstyleattr, int defstyleres) {     super(context, attrs, defstyleattr, defstyleres);     constructortask(); }   private void constructortask() {     x = 300;     y = 300;     radius = 100; }  @override public void setpressed(boolean pressed) {     super.setpressed(pressed);     log.i("button logger","button pressed"); }  @override protected  void ondraw(canvas canvas) {     super.ondraw(canvas);     canvas.drawcircle(x, y, radius, gameview.green);     log.i("drawing status", "circlebutton drawing..."); }  } 

i have single activity. activity contains relative layout single custom view.

here custom view:

public class gameview extends view {  public static paint green = new paint();  public gameview(context context) {     super(context);     green.setargb(255,0,255,0); }  public gameview(context context, attributeset attrs) {     super(context, attrs);     green.setargb(255, 0, 255, 0);  }  public gameview(context context, attributeset attrs, int defstyleattr) {     super(context, attrs, defstyleattr);     green.setargb(255, 0, 255, 0); }  @override protected void ondraw(canvas canvas) {     super.ondraw(canvas);     log.i("gameview draw status","drawing...");     main.testbutton.invalidate();     invalidate(); }  } 

and here activity code:

public class main extends appcompatactivity {  public static circlebutton testbutton;   @override protected void oncreate(bundle savedinstancestate) {     super.oncreate(savedinstancestate);     setcontentview(r.layout.activity_main);     testbutton = new circlebutton(getapplicationcontext());     makefullscreen();          relativelayout screenlayout = (relativelayout) findviewbyid(r.id.screenlayout);     screenlayout.addview(testbutton); }  private void makefullscreen() {...}   } 

for reason testbutton not being drawn. why not being drawn?

edit one: here xml have.

    <?xml version="1.0" encoding="utf-8"?> <relativelayout xmlns:android="http://schemas.android.com/apk/res/android"     xmlns:tools="http://schemas.android.com/tools"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:paddingbottom="0dp"     android:paddingleft="0dp"     android:paddingright="0dp"     android:paddingtop="0dp"     tools:context="com.example.vroy.customcirclebuttontest.main"     android:id="@+id/screenlayout">      <com.example.vroy.customcirclebuttontest.gameview         android:layout_width="match_parent"         android:layout_height="match_parent"         android:background="@color/black"         android:id="@+id/gamescreen" />   </relativelayout> 

edit two: did further debugging adding normal button relative layout , worked fine.

@override     protected void oncreate(bundle savedinstancestate) {         super.oncreate(savedinstancestate);         setcontentview(r.layout.activity_main);         testcirclebutton = new circlebutton(getapplicationcontext());         makefullscreen();          testbutton = new button(getapplicationcontext());         testbutton.setx(100);         testbutton.sety(100);         testbutton.settext("hello world");          relativelayout screenlayout = (relativelayout) findviewbyid(r.id.screenlayout);         screenlayout.addview(testcirclebutton);         screenlayout.addview(testbutton);          log.i("button status","adding button layout");     } 

for reason circlebutton not working normal button is.

you not specifying size of view (layout_width , layout_height), , view getting rendered inside 0px 0px space , invisible. can set programatically using layoutparams before adding views layout.

for example absolute size:

testbutton.setlayoutparams(new viewgroup.layoutparams(100,100)); 

although keep in mind difference between px , dip. want set values using internal radius attribute instead of harcoding them.