Drawing Circles using Canvas and Framelayout android

I am trying to create an app that displays a circle everytime I click a button. I have the layout looking great but when i click the button(circle) to display a circle on the screen nothing happens. I'm not confident that my draw circle class is being called correctly in my main activity. Here is my code below.

 package com.example.randomcircles;

 import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.graphics.Canvas;
 import android.graphics.Paint;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.Button;
 import android.widget.FrameLayout;

public class DisplayRandomCircles extends Activity
{
  DrawCircle c;
  Canvas d;
  @Override
public void onCreate(Bundle b)
{
    super.onCreate(b);
    setContentView(R.layout.activity_display_random_circles);
    Button btn1 = (Button) findViewById(R.id.btn1);
    Button btn2 = (Button) findViewById(R.id.btn2);
    c = new DrawCircle(getApplicationContext());
    d = new Canvas();
    FrameLayout f1 = (FrameLayout) findViewById(R.id.frame);

}
@SuppressLint("WrongCall")
public void doit(View v)
{
    switch (v.getId())
    {
        case (R.id.btn1):
            c.onDraw(d);
            break;

        case (R.id.btn2):
            break;
    }
}
}

Here is my DrawCircle class

package com.example.randomcircles;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.view.View;

public class DrawCircle extends View
{
public DrawCircle(Context con)
{
    super(con);
}
@Override
protected void onDraw(Canvas c)
{
    super.onDraw(c);
    Paint p = new Paint(Paint.ANTI_ALIAS_FLAG);
    p.setAntiAlias(true);
    p.setStyle(Paint.Style.STROKE);
    p.setStrokeWidth(100);
    p.setColor(Color.RED);
    p.setStyle(Paint.Style.FILL);
    c.drawCircle(75, 75, 100, p);
}
}

And my layout xml

<LinearLayout xmlns:android="http://ift.tt/nIICcg"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<FrameLayout
    android:id="@+id/frame"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_weight=".75"
    android:orientation="vertical" >


</FrameLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_weight=".25"
    android:gravity="bottom|center"
    android:orientation="horizontal" >

    <Button
        android:id="@+id/btn1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="start|bottom"
        android:layout_weight=".50"
        android:onClick="doit"
        android:text="@string/Circle" />

    <Button
        android:id="@+id/btn2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_weight=".50"
        android:layout_gravity="end|bottom"
        android:onClick="doit"
        android:text="@string/Clear" />
</LinearLayout>

</LinearLayout>