Android main.xml隐藏视图帮助

我无法同时显示setContentView（R.layout.main）和视图。我认为我没有正确理解这个概念。谁能告诉我哪里出了问题。多谢各位//请阅读代码中的注释

我正在尝试使用BitmapFactory在main.xml上显示图像

   public class TryGraph extends Activity 
 {

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);//I think this is where I need your help
    setContentView(new myView(this));//I want this to be displayed in main.xml
}

private class myView extends View{

    public myView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
    }

    @Override
    protected void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        Bitmap myBitmap = BitmapFactory.decodeResource(getResources(), R.drawable.sinewave);
        Bitmap resizedBitmap = Bitmap.createBitmap(myBitmap, 0, 0,
                300, 143);
        canvas.drawBitmap(resizedBitmap, 60, 50, null);
        Paint myPaint = new Paint();
        myPaint.setColor(Color.RED);
        myPaint.setStyle(Paint.Style.STROKE);
        myPaint.setStrokeWidth(5);
        canvas.drawRect(250,255,260,250, myPaint);

    }
}

}

XML文件是

---

当您调用

setContentView

时，您正在告诉设备加载应显示给用户的整个布局。在大多数情况下，此视图将占据整个屏幕。现在这个布局文件被认为是根文件，可能包含子视图，其中一个应该是ImageView

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    >
<TextView   
    android:id="@+id/banner"
    android:text="hello world"
    >  
<ImageView
    android:id="@+id/myImageView"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:src="@drawable/sampleimage"
    />
<?LinearLayout>