Android中Gallery和ImageSwitcher同步自动(滚动)播放图片库

<?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:layout_width="fill_parent"  
        android:layout_height="wrap_content" android:text="@string/hello" />  
    <ImageSwitcher android:id="@+id/myimgSwitcher" android:layout_gravity="center"  
        android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginBottom="20dip"></ImageSwitcher>  
    <Gallery android:id="@+id/mygallery" android:layout_width="fill_parent"  
        android:layout_height="wrap_content" android:background="#8A2BE2"></Gallery>  
</LinearLayout>  

package com.lover.qinjun;

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

import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.AdapterView;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.ViewSwitcher.ViewFactory;

public class MainActivity extends Activity implements ViewFactory {
    private static String TAG = "Gallery_Auto";
    private static int MSG_UPDATE = 1;

    private int count_drawble = 0;
    private int cur_index = 0;
    private boolean isalive = true; 、//线程循环运行的条件 
    private ImageSwitcher imgSwitcher;
    private Gallery mgallery;
    // 为Gallery控件设置Adapter
    private ImageAdapter imgAdapter = null;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        imgSwitcher = (ImageSwitcher) findViewById(R.id.myimgSwitcher);
        mgallery = (Gallery) findViewById(R.id.mygallery);
        mgallery.setSpacing(3); //设置图片之间的间隔，如果不加设置 ，图片会叠加。设置为0，表示图片之间无间缝。
        // 设置监听事件 --->当Gallery中的Item处于选中并且被点击触发该事件 
        mgallery.setOnItemClickListener(new OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> arg0, View view,
                    int position, long arg3) {
                System.out.println("setOnItemClickListener");
//                imgSwitcher.setBackgroundResource(imgAdapter.getResId(position));
            }
        });
        //当Gallery中的Item处于选中并且被点击触发该事件   ，在该监听事件中，保证图片播放的同步性
        mgallery.setOnItemSelectedListener(new OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> arg0, View view,
                    int position, long arg3) {
                 System.out.println("setOnItemSelectedListener");
                 //这儿不能通过setImageResource()设置图片 
                 imgSwitcher.setBackgroundResource(imgAdapter.getResId(position));
            }
            @Override
            public void onNothingSelected(AdapterView<?> arg0) {

            }
        });
        //构建适配器，并且分配
        imgAdapter = new ImageAdapter(this);
        mgallery.setAdapter(imgAdapter);
        count_drawble = imgAdapter.getCount();

        // 利用线程来更新 当前欲显示的图片id， 调用handler来选中当前图片
        new Thread(new Runnable() {
            @Override
            public void run() {
                // TODO Auto-generated method stub
                while (isalive) {
                    cur_index = cur_index % count_drawble;  // 图片区间[0,count_drawable)
                    Log.i(TAG, "cur_index"+ cur_index +" count_drawble --"+ count_drawble);
                    //msg.arg1 = cur_index 
                    Message msg = mhandler.obtainMessage(MSG_UPDATE, cur_index,    0);
                    mhandler.sendMessage(msg);
                    //更新时间间隔为 2s 
                    try {
                        Thread.sleep(2000);
                    } catch (InterruptedException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                    cur_index++;  //放置在Thread.sleep(2000) ；防止mhandler处理消息的同步性，导致cur_index>=count_drawble
                }
            }
        }).start();
    }
    //通过handler来更新主界面  mgallery.setSelection(positon),选中第position的图片，然后调用OnItemSelectedListener监听改变图像
    private Handler mhandler = new Handler() {
        public void handleMessage(Message msg) {
            if (msg.what == MSG_UPDATE) {
                Log.i(TAG, "cur_index"+ cur_index);
                mgallery.setSelection(msg.arg1);
                //UI Thread直接更改图片 ，不利用Gallery.OnItemSelectedListener监听更改
                //imgSwitcher.setBackgroundResource(imgAdapter.getResId(msg.arg1));
            }
        }
    };

    public void onDestroy() {
        super.onDestroy();
        isalive = false;
    }

    @Override
    public View makeView() {   //ImageSwitcher的ViewFactory方法
        // TODO Auto-generated method stub
        ImageView img = new ImageView(this);
        return img;
    }

    // 为Gallery控件提供适配器的类
    class ImageAdapter extends BaseAdapter {
        private Context mcontext;
        private ArrayList<Integer> residList = new ArrayList<Integer>(); // 通过放射机制保存所有图片的id

        public ImageAdapter(Context context) {
            mcontext = context;
            // 反射的可重用性更好
            // R.id在R文件中本质上是一个类，我们通过这个R.id.class.getClass().getDeclaredFields()可以找到它的所有属性
            Field[] residFields = R.drawable.class.getDeclaredFields();
            for (Field residField : residFields) {
                // 例如： public static final int icon=0x7f020000;
                // 它的Field表示为 : name= icon ; field.getInt() = 0x7f020000
                if (!"icon".equals(residField.getName())) {
                    int resid;
                    try {
                        resid = residField.getInt(null);// 找到该属性的值
                        residList.add(resid);
                    } catch (IllegalArgumentException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    } catch (IllegalAccessException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }
                }
            }
        }

        @Override
        public int getCount() {
            Log.e(TAG, " " + residList.size());
            return residList.size();
        }

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

        @Override
        public long getItemId(int position) {
            return 0;
        }
        //得到该图片的res id
        public int getResId(int position) {
            return residList.get(position);
        }

        @Override
        public View getView(int position, View convertView, ViewGroup parent) {
            ImageView img;
            if (convertView == null) {
                img = new ImageView(mcontext);
                img.setScaleType(ImageView.ScaleType.FIT_XY);
                img.setLayoutParams(new Gallery.LayoutParams(100, 100)); // 图片显示宽和长
                img.setImageResource(residList.get(position));
            } else {
                img = (ImageView) convertView;
            }
            return img;
        }

    }
}