title: Subclass Button with Android : lots of errors
body: <p>I tried to subclass <code>Button</code> , but I have a lot of errors when launching my project. Could you have a look and tell me how to fix this? (I've got maybe 50 errors coming up)</p>
  
  <pre><code>package my.project.name;
  
  import android[...]
  
  public class MyButton extends Button {
  
      public MyButton(){
          super(null);
      }
  
      public MyButton(Context context){
          super(context);
      }
  
      public MyButton(Context context, AttributeSet attrs){
          super(context, attrs);
      }
  
      public MyButton(Context context, AttributeSet attrs, int defStyle){
          super(context, attrs, defStyle);
      }
  
      @Override 
      protected void onDraw(Canvas canvasObject) {
          super.onDraw(canvasObject);
          int x = 100;
          int y = 100;
          int width = 80;
          int height = 200;
          Paint thePaint = new Paint();   
          thePaint.setColor(Color.WHITE);
          RectF rectangle1 = new RectF(x,y,x+width,y+height);
          canvasObject.drawRoundRect(rectangle1, 10.0f, 10.0f, thePaint);   
      }
  
  }
  </code></pre>
  
  <p>the main class :</p>
  
  <pre><code>package my.project.name;
  
  import android.app.Activity;
  import android.os.Bundle;
  
  public class MyProjectActivity extends Activity {
      /** Called when the activity is first created. */
      @Override
      public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.main);
      }
  }
  </code></pre>
  
  <p>and the xml :</p>
  
  <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent"
      android:orientation="vertical" &gt;
  
      &lt;TextView
          android:layout_width="fill_parent"
          android:layout_height="wrap_content"
          android:text="@string/hello" /&gt;
  
      &lt;MyButton
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:id="@+id/myb"
          android:tag="tag"
           /&gt;
  
  &lt;/LinearLayout&gt;
  </code></pre>
  
  <p>EDIT: actually, the rectangle does not show up, the subclass works, because i've got no error, but the rectangle is just not visible, even with the background to "@null"...</p>
  
  <p>Thanks a lot</p>