一个简单的android图片浏览器demo（待完善）

package com.kevin.picturebrowser;

import java.lang.reflect.Field;
import java.util.ArrayList;

import android.os.Bundle;
import android.app.Activity;
import android.app.ActionBar.LayoutParams;
import android.view.Menu;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.view.animation.AnimationUtils;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity implements ViewFactory
{

    private ImageSwitcher imageSwitcher1;
    private int downX,upX;
    private ArrayList<Integer> imgPool = new ArrayList<Integer>(); //图片库
    private int ImgPos = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        InitialPicturePool();
        InitialImageSwitcher();
        BindTouchListener();
        
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    private void InitialImageSwitcher()
    {
        imageSwitcher1 = (ImageSwitcher) findViewById(R.id.imageswitcher1);
        imageSwitcher1.setFactory(this);
        imageSwitcher1.setInAnimation(AnimationUtils.loadAnimation(this,
                android.R.anim.fade_in));
        imageSwitcher1.setOutAnimation(AnimationUtils.loadAnimation(this,
                android.R.anim.fade_out));
        imageSwitcher1.setImageResource(imgPool.get(0));
    }

    private void BindTouchListener()
    {
        imageSwitcher1.setOnTouchListener(new OnTouchListener()
        {

            @Override
            public boolean onTouch(View v, MotionEvent event)
            {
                if (event.getAction() == MotionEvent.ACTION_DOWN)
                {
                    downX = (int) event.getX(); //取得按下时的坐标
                    return true;
                }
                else if(event.getAction() == MotionEvent.ACTION_UP)
                {
                    upX = (int) event.getX(); //取得松开时的坐标
                    if(upX - downX > 100)
                    {
                        imageSwitcher1.setInAnimation(AnimationUtils.loadAnimation(
                                MainActivity.this, android.R.anim.slide_in_left));
                        imageSwitcher1.setOutAnimation(AnimationUtils.loadAnimation(
                                MainActivity.this, android.R.anim.slide_out_right));
                        imageSwitcher1.setImageResource(GetPreviousPicture());
                    }
                    else if(downX - upX > 100)
                    {
                        imageSwitcher1.setInAnimation(AnimationUtils.loadAnimation(
                                MainActivity.this, android.R.anim.fade_in));
                        imageSwitcher1.setOutAnimation(AnimationUtils.loadAnimation(
                                MainActivity.this, android.R.anim.fade_out));
                        imageSwitcher1.setImageResource(GetNextPicture());
                    }
                }
                return false;
            }
        });
    }

    @Override
    public View makeView()
    {
        ImageView iv = new ImageView(this);
        iv.setBackgroundColor(0xFF000000);
        iv.setScaleType(ImageView.ScaleType.FIT_CENTER);
        iv.setLayoutParams(new ImageSwitcher.LayoutParams(
                LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
        return iv;
    }
    
    private void InitialPicturePool()
    {
         Field[] fields = R.drawable.class.getDeclaredFields();
         for(Field field : fields)
         {
             int index = 0;
             try
             {
                index = field.getInt(R.drawable.class); 
             }
             catch(IllegalArgumentException e)
             {
                 e.printStackTrace();
             }
             catch(IllegalAccessException e)
             {
                 e.printStackTrace();
             }
             
             imgPool.add(index);
         }
    }
    
    private  Integer GetNextPicture()
    {    
        ImgPos++;
        if(ImgPos > imgPool.size()-1)
            ImgPos = 0;
        
        return imgPool.get(ImgPos);
    }
    
    private Integer GetPreviousPicture()
    {
        ImgPos--;
        if(ImgPos < 0)
            ImgPos = imgPool.size()-1;
        
        return imgPool.get(ImgPos);
    }
}

XML：

<RelativeLayout 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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MainActivity" >

    <ImageSwitcher
    　　android:id="@+id/imageswitcher1"
    　　android:layout_width="fill_parent"
    　　android:layout_height="fill_parent"
    　　android:layout_centerVertical="true">
    </ImageSwitcher>
   
</RelativeLayout>