Android ViewPager真正的实现无限循环滚动

Android ViewPager真正的实现无限循环滚动

在存放View的集合中的第一个位置放入真正的最后一个View，而在最后一个放入第一个。具体请参照下图以及代码！

1. package com.xinye.ui;
2.  
3. import java.util.ArrayList;
4. import java.util.HashMap;
5.  
6. import net.tsz.afinal.FinalBitmap;
7. import net.tsz.afinal.FinalHttp;
8. import net.tsz.afinal.http.AjaxCallBack;
9.  
10. import org.json.JSONArray;
11. import org.json.JSONException;
12. import org.json.JSONObject;
13.  
14. import android.graphics.Color;
15. import android.support.v4.view.PagerAdapter;
16. import android.support.v4.view.ViewPager;
17. import android.support.v4.view.ViewPager.OnPageChangeListener;
18. import android.util.Log;
19. import android.view.LayoutInflater;
20. import android.view.View;
21. import android.view.ViewGroup;
22. import android.widget.ImageView;
23. import android.widget.ImageView.ScaleType;
24. import android.widget.TextView;
25. import android.widget.Toast;
26.  
27. import com.xinye.R;
28. import com.xinye.domain.Bargain;
29. import com.xinye.domain.Screen;
30. import com.xinye.domain.ViewFrame;
31. import com.xinye.util.ApplicationUtils;
32. import com.xinye.util.ConstantsUtils;
33. import com.xinye.util.FileUtils;
34. import com.xinye.util.ImagePathUtils;
35. import com.xinye.util.LogUtils;
36. import com.xinye.util.StringUtils;
37. import com.xinye.view.SlidingView;
38.  
39. /**
40.  * Fragment
41.  *
42.  *
43.  *
44.  */
45. public class BannerFragment extends BaseFragment implements OnPageChangeListener {
46.    // 当前Fragment的RootView
47.    private View mRootView = null;
48.    // 当前Fragment中的ViewPager
49.    private ViewPager mViewPager = null;
50.    // 展示当前页面标识的TextView
51.    private TextView mTextView = null;
52.    // 布局填充器对象
53.    private LayoutInflater mLayoutInflater = null;
54.    // 保存Bargain信息的ArrayList
55.    private ArrayList<Bargain> mBargainList = new ArrayList<Bargain>();
56.    // 保存所有的ViewPager的View
57.    private ArrayList<ImageView> mViewList = new ArrayList<ImageView>();
58.    // Bitmap载入工具类
59.    private FinalBitmap mFinalBitmap;
60.    // 切换到左边的ImageView
61.    private ImageView mToLeftImageView = null;
62.    // 切换到右侧的ImageView
63.    private ImageView mToRightImageView = null;
64.    // 图片URL列表
65.    private static ArrayList<String> mImageUrlList = new ArrayList<String>();
66.    @Override
67.    protected void initContent() {
68.       mFinalBitmap = FinalBitmap.create(mActivity, FileUtils.getCacheDirectory(mActivity));
69.       mTopbarTextView.setText(R.string.popup_banner);
70.       mPopupBannerTextView.setTextColor(Color.argb(0xff, 0xa1, 0x01, 0x01));
71.       mTopbarLeftImageView.setImageResource(R.drawable.topbar_banner);
72.  
73.       mLayoutInflater = mActivity.getLayoutInflater();
74.  
75.       mRootView = mLayoutInflater.inflate(R.layout.fragment_banner, null);
76.       mbaseLinearLayout.addView(mRootView);
77.  
78.       mViewPager = (ViewPager) mRootView.findViewById(R.id.bannerFragmentViewPager);
79.       mTextView = (TextView) mRootView.findViewById(R.id.countBannerFragmentTextView);
80.  
81.       mToLeftImageView = (ImageView) mRootView.findViewById(R.id.toLeftBannerFragmentImageView);
82.       mToLeftImageView.setOnClickListener(BannerFragment.this);
83.  
84.       mToRightImageView = (ImageView) mRootView.findViewById(R.id.toRightBannerFragmentImageView);
85.       mToRightImageView.setOnClickListener(BannerFragment.this);
86.  
87.       try {
88.          if(mImageUrlList != null && mImageUrlList.size() > 0){
89.             initViewPager();
90.          }else{
91.             initData();
92.          }
93.       } catch (Exception e) {
94.          e.printStackTrace();
95.       }
96.    }
97.  
98.    // 初始化数据
99.    private void initData() throws Exception {
100.       HashMap<String, Object> data = new HashMap<String, Object>();
101.       data.put("loginUserId", UserLoginActivity.userID);
102.       data.put("checkStr", UserLoginActivity.token);
103.       data.put("isMember", UserLoginActivity.isMember);
104.       String url = StringUtils.composeUrl(ConstantsUtils.BANNER_LIST_URL, data);
105.       LogUtils.printLog(Log.INFO, LogUtils.LOG_TAG, "BannerFragment initData url = " + url);
106.       new FinalHttp().get(url, new AjaxCallBack<String>() {
107.          @Override
108.          public void onSuccess(String t) {
109.             LogUtils.printLog(Log.INFO, LogUtils.LOG_TAG, "banner list JSON:" + t);
110.             parseJSON(t);
111.             super.onSuccess(t);
112.          }
113.  
114.          @Override
115.          public void onFailure(Throwable t, String strMsg) {
116.             if(t != null){
117.                mImageUrlList = FileUtils.readListFromFile(mActivity, FileUtils.LIST_BANNER_FILE_NAME);
118.                if(mImageUrlList != null){
119.                   initViewPager();
120.                }
121.             }
122.             super.onFailure(t, strMsg);
123.          }
124.       });
125.  
126.    }
127.  
128.    // 解析JSON
129.    private void parseJSON(String t) {
130.       if (t == null) {
131.          return;
132.       }
133.       try {
134.          JSONObject tObj = new JSONObject(t);
135.          int status = tObj.getInt("status");
136. // String message = tObj.getString("message");
137.          if (status == 0) {
138.             String dataString = tObj.getString("data");
139.             if (dataString != null && !dataString.equalsIgnoreCase("null")) {
140.                JSONObject dataObj = new JSONObject(dataString);
141.                String partnerBargainFormListString = dataObj.getString("partnerBargainFormList");
142.                if (partnerBargainFormListString != null && !partnerBargainFormListString.equalsIgnoreCase("null")) {
143.                   JSONArray array = new JSONArray(partnerBargainFormListString);
144.                   Screen screen = ApplicationUtils.getScreen(mActivity);
145.                   if (array != null) {
146.                      int len = array.length();
147.                      for (int i = 0; i < len; i++) {
148.                         JSONObject obj = array.getJSONObject(i);
149.                         String bargainString = obj.getString("partnerBargain");
150.                         Bargain bargain = new Bargain();
151.                         if (bargainString != null && !bargainString.equalsIgnoreCase("null")) {
152.                            JSONObject bargainObj = new JSONObject(bargainString);
153.                            bargain.partnerCategoryId = bargainObj.getLong("partnerCategoryId");
154.                            bargain.partnerId = bargainObj.getLong("partnerId");
155.                            bargain.pictureId = bargainObj.getLong("pictureId");
156.                            bargain.title = bargainObj.getString("title");
157.                            bargain.displayOrder = bargainObj.getLong("displayOrder");
158.                            bargain.dailySpecialsId = bargainObj.getLong("dailySpecialsId");
159.                            bargain.bargainId = bargainObj.getLong("bargainId");
160.                         }
161.                         String pic = obj.getString("pic");
162.                         pic = ImagePathUtils.getBannerRealPath(pic,screen);
163.                         bargain.pic = pic;
164.                         mBargainList.add(bargain);
165.                         mImageUrlList.add(bargain.pic);
166.                      }
167.                      FileUtils.writeListToFile(mActivity, FileUtils.LIST_BANNER_FILE_NAME, mImageUrlList);
168.                      initViewPager();
169.                   }
170.                } else {
171.                   return;
172.                }
173.             } else {
174.                return;
175.             }
176.          }
177.       } catch (JSONException e) {
178.          e.printStackTrace();
179.       }
180.    }
181.  
182.    // 初始化ViewPager
183.    private void initViewPager() {
184.       if(!(mImageUrlList != null && mImageUrlList.size() > 0)){
185.          return;
186.       }
187.       int length = mImageUrlList.size() + 2;
188.       for (int i = 0; i < length; i++) {
189.          ImageView mViewPagerImageView = new ImageView(mActivity);
190.          ViewGroup.LayoutParams viewPagerImageViewParams =
191.                new ViewGroup.LayoutParams(ViewGroup.LayoutParams.FILL_PARENT,
192.                      ViewGroup.LayoutParams.FILL_PARENT);
193.          mViewPagerImageView.setLayoutParams(viewPagerImageViewParams);
194.          mViewPagerImageView.setScaleType(ScaleType.FIT_XY);
195.          mViewPagerImageView.setOnClickListener(BannerFragment.this);
196.          mViewList.add(mViewPagerImageView);
197.       }
198.       if (mViewList != null && mViewList.size() > 0) {
199.          mViewPager.setAdapter(new ViewpagerAdapter());
200.       }
201.       mViewPager.setOnPageChangeListener(BannerFragment.this);
202.  
203.       if (mImageUrlList.size() == 0) {
204.          mTextView.setText(String.format("0 / %s", mImageUrlList.size()));
205.       } else {
206.          mTextView.setText(String.format("1 / %s", mImageUrlList.size()));
207.       }
208.       mViewPager.setCurrentItem(1);
209.       if (mActivity.getSlidingMenu() != null && mActivity.getSlidingMenu().getSlidingView() != null) {
210.  
211.          SlidingView sv = mActivity.getSlidingMenu().getSlidingView();
212.          sv.setOnInterceptListener(new SlidingView.OnInterceptListener() {
213.             @Override
214.             public ViewFrame getInterceptViewFrame() {
215.                ViewFrame frame = new ViewFrame(0, 50, mViewPager.getWidth(), mViewPager.getHeight());
216.                return frame;
217.             }
218.          });
219.       }
220.    }
221.    @Override
222.    protected void init() {
223.  
224.    }
225.    /**
226.     * PagerAdapter
227.     * @author
228.     *
229.     */
230.    class ViewpagerAdapter extends PagerAdapter {
231.       @Override
232.       public void destroyItem(View container, int position, Object object) {
233.          ImageView view = mViewList.get(position % mViewList.size());
234.          ((ViewPager) container).removeView(view);
235.          view.setImageBitmap(null);
236.       }
237.  
238.       @Override
239.       public Object instantiateItem(View container, int position) {
240.          ((ViewPager) container).addView(mViewList.get(position));
241.             return mViewList.get(position);
242.       }
243.  
244.       @Override
245.       public int getCount() {
246.          return mViewList.size();
247.       }
248.  
249.       @Override
250.       public boolean isViewFromObject(View view, Object object) {
251.          return view == object;
252.       }
253.    }
254.  
255.    @Override
256.    public void onPageScrollStateChanged(int state) {
257.  
258.    }
259.  
260.    @Override
261.    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
262.  
263.    }
264.  
265.    @Override
266.    public void onPageSelected(int position) {
267.       if(position == 0){
268.          mFinalBitmap.display(mViewList.get(position), mImageUrlList.get(mImageUrlList.size() - 1));
269.       }else if(position == mViewList.size() - 1){
270.          mFinalBitmap.display(mViewList.get(position), mImageUrlList.get(0));
271.       }else{
272.          mFinalBitmap.display(mViewList.get(position), mImageUrlList.get(position - 1));
273.       }
274.       int pageIndex = position;
275.        if(position == 0){
276.           pageIndex = mImageUrlList.size();
277.        }else if(position == mImageUrlList.size() + 1){
278.           pageIndex = 1;
279.        }
280.        if(position != pageIndex){
281.           mViewPager.setCurrentItem(pageIndex, false);
282.           return;
283.        }
284.        int count = mViewList.size() - 2;
285.        if(mViewList != null && count > 0){
286.           int index = (position);
287.           String text = index + "/" + count;
288.           mTextView.setText(text);
289.        }else{
290.          String text = 0 + " / " + 0;
291.          mTextView.setText(text);
292.        }
293.    }
294.  
295.    @Override
296.    public void onClick(View v) {
297.       switch (v.getId()) {
298.       // 切换到左边的ImageView
299.       case R.id.toLeftBannerFragmentImageView: {
300.          if (mViewPager != null && mViewPager.getCurrentItem() > 0) {
301.             mViewPager.setCurrentItem(mViewPager.getCurrentItem() - 1, true);
302.          } else {
303.             Toast.makeText(mActivity, R.string.banner_is_first, Toast.LENGTH_SHORT).show();
304.          }
305.       }
306.          break;
307.       // 切换到右边的ImageView
308.       case R.id.toRightBannerFragmentImageView: {
309.          if (mViewPager != null && mViewList != null && mViewPager.getCurrentItem() < Integer.MAX_VALUE - 1) {
310.             mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1, true);
311.          } else {
312.             Toast.makeText(mActivity, R.string.banner_is_last, Toast.LENGTH_SHORT).show();
313.          }
314.       }
315.          break;
316.       }
317.       super.onClick(v);
318.    }
319.  
320.    @Override
321.    public void onPause() {
322.       if (mFinalBitmap != null) {
323.          mFinalBitmap.onPause();
324.       }
325.       super.onPause();
326.    }
327.  
328.    @Override
329.    public void onResume() {
330.       if (mFinalBitmap != null) {
331.          mFinalBitmap.onResume();
332.       }
333.       super.onResume();
334.    }
335.  
336.    @Override
337.    public void onDestroy() {
338.       if (mFinalBitmap != null) {
339.          mFinalBitmap.onDestroy();
340.       }
341.       super.onDestroy();
342.    }
343. }