求教Framelayout布局问题

  想在LinearLayout下嵌套一个Framelayout,xml文件如下：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button" />    <FrameLayout
        android:id="@+id/layout"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        android:orientation="vertical" >        <ListView
            android:id="@+id/listView1"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" >
        </ListView>
    </FrameLayout></LinearLayout>
  程序代码：
  package com.circle.test;import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.os.Bundle;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.FrameLayout;
import android.widget.FrameLayout.LayoutParams;
import android.widget.ListView;public class Test_CircleActivity extends Activity {
private Button btn;
private FrameLayout layout;
private FrameLayout.LayoutParams params1;
private ListView lv;
private String items[] = {"a","b","c","d","e","f","g","h","i"};
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        
        btn = (Button)findViewById(R.id.button1);
        layout = (FrameLayout)findViewById(R.id.layout);
        params1 = new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
        MyView view1 = new MyView(this);
        layout.addView(view1, params1);
        lv = (ListView)findViewById(R.id.listView1);
        ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_expandable_list_item_1, items);
        lv.setAdapter(adapter);
    }
    public class MyView extends View{ public MyView(Context context) {
super(context);
}
     @Override
     protected void onDraw(Canvas canvas) {
    
     super.onDraw(canvas);
     Paint paint = new Paint();
paint.setColor(Color.RED);
paint.setStyle(Style.STROKE);

canvas.drawCircle(200, 200, 10, paint);
canvas.drawCircle(100, 200, 10, paint);
canvas.drawCircle(220, 200, 10, paint);

     }
    }
}程序运行报错：ava.lang.RuntimeException: Unable to start activity ComponentInfo{com.circle.test/com.circle.test.Test_CircleActivity}: java.lang.ClassCastException: android.widget.FrameLayout
  求助高人帮我看下，哪里出错了？