ViewPage

public class MainActivity extends Activity {

    private ViewPager vp;
    private List<Img> list=new ArrayList<Img>();
    private String Urlpath="http://172.17.29.120/localuser/ljy/ndhx/pic.json";
    private BitmapUtils bitmapUtils;
    private Button bt;
    private Handler handler=new Handler(){
        private Img[] imgs;

        public void dispatchMessage(Message msg) {
            switch (msg.what) {
            case 0:
                String result=(String) msg.obj;
                Gson gson = new Gson();
                imgs = gson.fromJson(result, Img[].class);
                vp.setOnPageChangeListener(new OnPageChangeListener() {

                    @Override
                    public void onPageSelected(int arg0) {
                        if(arg0==imgs.length-1){
                            bt.setVisibility(View.VISIBLE);
                        }else{
                            bt.setVisibility(View.INVISIBLE);
                        }
                    }

                    @Override
                    public void onPageScrolled(int arg0, float arg1, int arg2) {
                        // TODO Auto-generated method stub
                    }
                    @Override
                    public void onPageScrollStateChanged(int arg0) {
                        // TODO Auto-generated method stub

                    }
                });
                vp.setAdapter(new PagerAdapter() {

                    @Override
                    public boolean isViewFromObject(View arg0, Object arg1) {
                        // TODO Auto-generated method stub
                        return arg0==arg1;
                    }

                    @Override
                    public int getCount() {
                        // TODO Auto-generated method stub
                        return imgs.length;
                    }

                    @Override
                    public void destroyItem(ViewGroup container, int position,
                            Object object) {
                        container.removeView((View)object);
                    }

                    @Override
                    public Object instantiateItem(ViewGroup container,
                            int position) {
                        ImageView imageView = new ImageView(MainActivity.this);
                        bitmapUtils.display(imageView, "http://172.17.29.120/localuser/ljy/ndhx/"+imgs[position].src);
                        container.addView(imageView);
                        return imageView;
                    }
                });
                break;

            }
        };
    };
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        vp = (ViewPager) findViewById(R.id.vp);
        bt = (Button) findViewById(R.id.button1);
        bitmapUtils = new BitmapUtils(MainActivity.this);
        getResult();
    }
    private void getResult() {
        new Thread(){
            public void run() {
                try {
                    HttpClient httpClient=new DefaultHttpClient();
                    HttpGet httpGet=new HttpGet(Urlpath);
                    HttpResponse response = httpClient.execute(httpGet);
                    StatusLine statusLine = response.getStatusLine();
                    int code = statusLine.getStatusCode();
                    if (code==200) {
                        HttpEntity httpEntity = response.getEntity();
                        String result = EntityUtils.toString(httpEntity);
                        Message message = new Message();
                        message.what=0;
                        message.obj=result;
                        handler.sendMessage(message);
                    }

                } catch (ClientProtocolException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            };
        }.start();
    }
}
//这里是PageAdapter
public class MyAdapter extends BaseAdapter{
    private Img[] list;
    private Context context;
    private BitmapUtils bitmapUtils;
    public MyAdapter(Img[] list, Context context) {
        super();
        this.list = list;
        this.context = context;
        bitmapUtils = new BitmapUtils(context);
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return list.length;
    }

    @Override
    public Object getItem(int position) {
        // TODO Auto-generated method stub
        return null;
    }

    @Override
    public long getItemId(int position) {
        // TODO Auto-generated method stub
        return 0;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        View view=View.inflate(context, R.layout.item, null);
        ImageView img = (ImageView) view.findViewById(R.id.imageView1);
        bitmapUtils.display(img, "http://172.17.29.120/localuser/ljy/ndhx/"+list[position]);
        return view;
    }

}