为什么ImageView中显示不了位图文件？

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"

    android:layout_height="match_parent"

    android:orientation="vertical"

    android:background="#000000"

  >

    

    <TextView 

        android:text="测试位图资源"

        android:id="@+id/bitmapTextView01"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"></TextView>

    

    <ImageView 

        android:id="@+id/bitmapImageView01"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:src="@drawable/g1"></ImageView>

    

     <ImageView

        android:id="@+id/bitmapImageView02"

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"></ImageView>



</LinearLayout>

package com.amaker.ch03_resource.drawable;



import android.app.Activity;

import android.content.res.Resources;

import android.graphics.drawable.Drawable;

import android.os.Bundle;

import android.widget.ImageView;



public class TestBitmapActivity extends Activity {

	private ImageView myImageView;

	

	public void onCreat(Bundle savedInstanceState){

		super.onCreate(savedInstanceState);

		setContentView(R.layout.test_bitmap);

		myImageView=(ImageView)findViewById(R.id.bitmapImageView02);

		Resources r=getResources();

		Drawable d=r.getDrawable(R.drawable.moto);

		myImageView.setImageDrawable(d);

	}



}