Programmatically created "Circle Button" not drawing

Question

I have a 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 a single activity. This activity contains a relative layout with a single custom view.

Here is the 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 is the 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 some reason my testButton is not being drawn. Why is it not being drawn?

EDIT ONE: Here is the XML I 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: I did some further debugging by adding a normal button to the relative layout and it 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 To Layout");
    }

For some reason by circleButton is not working but a normal button is.

Answer 1

You are not specifying the size of the View (layout_width and layout_height), and thus your view is getting rendered inside a 0px by 0px space and thus invisible. You can set those programatically using LayoutParams before adding your views to the layout.

For example with absolute size:

testButton.setLayoutParams(new ViewGroup.LayoutParams(100,100));

Although keep in mind the difference between px and dip. You would probably want to set the values using your internal radius attribute instead of harcoding them.