<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent" 
    android:orientation="vertical">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="320dp"
        android:layout_height="320dp"/>
    <Gallery
        android:id="@+id/gallery"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_marginTop="25dp"
        android:unselectedAlpha="0.6"
        android:spacing="2pt" />
</LinearLayout>

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <declare-styleable name="Gallery">
        <attr name="android:galleryItemBackground" />
    </declare-styleable>  
</resources>

package com.example.gallery;
import android.app.Activity;
import android.content.res.TypedArray;
import android.os.Bundle;
import android.view.View;
import android.view.ViewGroup;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;

@SuppressWarnings("deprecation")
public class MainActivity extends Activity {

    int[] imageIds=new int[]{
        R.drawable.shuangzi,R.drawable.shuangyu,R.drawable.chunv,
        R.drawable.tiancheng,R.drawable.tianxie,R.drawable.sheshou,R.drawable.juxie,
        R.drawable.shuiping,R.drawable.shizi,R.drawable.baiyang,R.drawable.jinniu,R.drawable.mojie
    };
    Gallery gallery;
    ImageView imageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
gallery=(Gallery) findViewById(R.id.gallery);
imageView=(ImageView) findViewById(R.id.imageView);
BaseAdapter baseAdapter=new BaseAdapter(){

    @Override
    public int getCount() {
        return imageIds.length;
    }

    @Override
    public Object getItem(int position) {
        return position;
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView=new ImageView(MainActivity.this);
    imageView.setImageResource(imageIds[position]);
    imageView.setScaleType(ImageView.ScaleType.FIT_XY);
    imageView.setLayoutParams(new Gallery.LayoutParams(75,100));
    TypedArray typedArray = obtainStyledAttributes(
            R.styleable.Gallery);
    imageView.setBackgroundResource(typedArray.getResourceId(
            R.styleable.Gallery_android_galleryItemBackground, 0));
    return imageView;
    }
    
};
gallery.setAdapter(baseAdapter);
gallery.setOnItemSelectedListener(new OnItemSelectedListener(){

    @Override
    public void onItemSelected(AdapterView<?> parent, View view, int position,
            long id) {
        imageView.setImageResource(imageIds[position]);
        
    }

    @Override
    public void onNothingSelected(AdapterView<?> parent) {
    
    }
    
});
    }

    

}