无法使用新的JSON数据重新填充列表视图 - Java / Android

Question

我有一个listView，其中填充了从YouTube获得的JSON数据：

private VideosListView listView;

截至目前 - listView已成功填充我正在寻找的数据，但我需要能够使用更新的数据重新填充它。目前 - 我使用：

执行/填充初始listView

new GetYouTubeUserVideosTask(responseHandler, playlist).execute();  

我想做的是使用String播放列表的不同值重新填充它：

String playlist = "TheMozARTGROUP‎";
                    new GetYouTubeUserVideosTask(responseHandler, playlist)
                    .execute();

                    View vg = findViewById(R.layout.home);
                    vg.invalidate();

P.S。

到目前为止我尝试使用的东西似乎没有用 - 当我滑动ViewPager时没有任何反应 - 但是如果我在那里设置吐司，它会在刷卡时出现。

我不知道为什么这是一个如此难以解决的问题 - 但我很乐意通过PayPal为任何可以解决这个问题的人留下小费。

http://i.stack.imgur.com/e0QqU.png

JAVA：Home.java

public class Home extends YouTubeBaseActivity implements

VideoClickListener {
    private VideosListView listView;
    private int mCurrentTabPosition = NO_CURRENT_POSITION;
    private static final int NO_CURRENT_POSITION = -1;
    private ListView drawerListView;
    String playlist = "knocksteadyTV";
    Activity activity;
    int imageArray[];
    String[] stringArray;
    String runPrevious = "No";
    private OnPageChangeListener mPageChangeListener;
    ImagePagerAdapter adapter = new ImagePagerAdapter();

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.home);

        final ViewPager mPager = (ViewPager) findViewById(R.id.view_pager);
        adapter.notifyDataSetChanged();
        mPager.setAdapter(adapter);
        mPager.setOnPageChangeListener(mPageChangeListener);

        listView = (VideosListView) findViewById(R.id.videosListView);
        listView.setOnVideoClickListener(this);


        new GetYouTubeUserVideosTask(responseHandler, playlist).execute();      


        mPager.setOnPageChangeListener(new OnPageChangeListener() {

            @Override
            public void onPageSelected(int pos) {
                Toast.makeText(getApplicationContext(), "onPageSelected",
                        Toast.LENGTH_SHORT).show();

                String playlist = "TheMozARTGROUP‎";

                new GetYouTubeUserVideosTask(responseHandler, playlist).execute();  
                adapter.notifyDataSetChanged();

            }

            @Override
            public void onPageScrolled(int arg0, float arg1, int arg2) {
                // TODO Auto-generated method stub
                // Toast.makeText(getApplicationContext(), "onPageScrolled",
                // Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onPageScrollStateChanged(int pos) {
                Toast.makeText(getApplicationContext(),
                        "onPageScrollStateChanged", Toast.LENGTH_SHORT).show();
                String playlist = "TheMozARTGROUP‎";
                 new GetYouTubeUserVideosTask(responseHandler, playlist)
                 .execute();
                 adapter.notifyDataSetChanged();

            }
        });



        mPageChangeListener = new ViewPager.SimpleOnPageChangeListener() {

            @Override
            public void onPageSelected(int position) {
                onTabChanged(mPager.getAdapter(), mCurrentTabPosition, position);
                position = mCurrentTabPosition;
                int oldPos = mPager.getCurrentItem();
                if (position > oldPos) {

                    System.out.print(position);
                    // Moving to the right
                    String playlist = "TheMozARTGROUP‎";
                    new GetYouTubeUserVideosTask(responseHandler, playlist)
                    .execute();

                    View vg = findViewById(R.layout.home);
                    vg.invalidate();

                } else if (position < oldPos) {
                    // Moving to the Left
                    System.out.print(position);
                    String playlist = "TheMozARTGROUP‎";
                    new GetYouTubeUserVideosTask(responseHandler, playlist)
                    .execute();

                    View vg = findViewById(R.layout.home);
                    vg.invalidate();

                }
                mPager.setOnPageChangeListener(mPageChangeListener);
            }

            private void onTabChanged(PagerAdapter adapter,
                    int mCurrentTabPosition, int position) {
                // TODO Auto-generated method stub

            }
        };}

    private class MyActivityGetYouTubeUserVideosTask extends GetYouTubeUserVideosTask {
        public MyActivityGetYouTubeUserVideosTask(Handler replyTo,
                String username) {
            super(replyTo, username);
            // TODO Auto-generated constructor stub
        }

        @Override
        protected void onPostExecute(Void result) {
            if (result != null) {
                // TODO update your list data
                // note: assuming your data is stored in an ArrayList<MyData>,
                // you cannot create a new one. you must clear() the current
                // ArrayList and add() the result to it.
            }
            adapter.notifyDataSetChanged();
        }
    }

    private void _initMenu() {

        }

    Handler replyTo = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            populateListWithVideos(msg);
        };
    };


    Handler responseHandler = new Handler() {
        @Override
        public void handleMessage(Message msg) {
            populateListWithVideos(msg);
        };
    };

    private void populateListWithVideos(Message msg) {
        Library lib = (Library) msg.getData().get(
                GetYouTubeUserVideosTask.LIBRARY);
        listView.setVideos(lib.getVideos());
    }

    @Override
    protected void onStop() {
        responseHandler = null;
        super.onStop();
    }

    @Override
    public void onVideoClicked(Video video) {
        Intent intent = new Intent(this, Player.class);
        intent.putExtra("id", video.getId());
        intent.putExtra("title", video.getTitle());
        intent.putExtra("uploader", video.getUploader());
        intent.putExtra("viewCount", video.getviewCount());
        startActivity(intent);
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        actionBarDrawerToggle.onConfigurationChanged(newConfig);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        MenuInflater inflater = getMenuInflater();
        inflater.inflate(R.menu.main, menu);
        return super.onCreateOptionsMenu(menu);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

        if (actionBarDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    private class ImagePagerAdapter extends PagerAdapter {
        public ImagePagerAdapter(Activity act, int[] mImages,
                String[] stringArra) {
            imageArray = mImages;
            activity = act;
            stringArray = stringArra;
        }

        // this is your constructor
        public ImagePagerAdapter() {
            super();

        }

        private int[] mImages = new int[] { R.drawable.selstation_up_btn,
                R.drawable.classical_up_btn, R.drawable.country_up_btn,
                R.drawable.dance_up_btn, R.drawable.hiphop_up_btn,
                R.drawable.island_up_btn, R.drawable.latin_up_btn,
                R.drawable.pop_up_btn, R.drawable.samba_up_btn };

        private String[] stringArray = new String[] { "vevo",
                "TheMozARTGROUP‎", "TimMcGrawVEVO‎", "TiestoVEVO‎",
        "EminemVEVO‎" };

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

        @Override
        public boolean isViewFromObject(View view, Object object) {
            return view == ((ImageView) object);
        }

        @Override
        public Object instantiateItem(ViewGroup container, int position) {
            Context context = Home.this;
            ImageView imageView = new ImageView(context);
            imageView.setScaleType(ScaleType.FIT_XY);
            imageView.setImageResource(mImages[position]);
            ((ViewPager) container).addView(imageView, 0);
            return imageView;
        }

        public void destroyItem(ViewGroup container, int position, Object object) {
            ((ViewPager) container).removeView((ImageView) object);
        }

        private class DrawerItemClickListener implements
        ListView.OnItemClickListener {

            @Override
            public void onItemClick(AdapterView parent, View view,
                    int position, long id) {

                drawerListView.setItemChecked(position, true);
                setTitle("......");

                String text = "menu click... should be implemented";
                Toast.makeText(Home.this, text, Toast.LENGTH_LONG).show();
                drawerLayout.closeDrawer(drawerListView);

            }



            }
        }
    }

JAVA：GetYoutubeVideosTask.java

public class GetYouTubeUserVideosTask extends AsyncTask<Void, Void, Void> {

    public static final String LIBRARY = "Library";
    private final Handler replyTo;
    private final String username;

    public GetYouTubeUserVideosTask(Handler replyTo, String username) {
       this.replyTo = replyTo;
       this.username = username;
    }
   /* 
    * @see android.os.AsyncTask#doInBackground(Params[])
    */
   @Override
   protected Void doInBackground(Void... arg0) {
       try {

         HttpClient client = new DefaultHttpClient();

         HttpUriRequest request = new HttpGet("https://gdata.youtube.com/feeds/api/videos?author="+username+"&v=2&alt=jsonc");

         HttpResponse response = client.execute(request);

         String jsonString = StreamUtils.convertToString(response.getEntity().getContent());

         JSONObject json = new JSONObject(jsonString);
         JSONArray jsonArray = json.getJSONObject("data").getJSONArray("items");


         List<Video> videos = new ArrayList<Video>();

         for (int i = 0; i < jsonArray.length(); i++) {
             JSONObject jsonObject = jsonArray.getJSONObject(i);

             String title = jsonObject.getString("title");
             String id = jsonObject.getString("id");
             String viewCount = jsonObject.getString("viewCount");
             String uploader = jsonObject.getString("uploader");
             String url;
             try {
                 url = jsonObject.getJSONObject("player").getString("mobile");
             } catch (JSONException ignore) {
                 url = jsonObject.getJSONObject("player").getString("default");
             }
             String thumbUrl = jsonObject.getJSONObject("thumbnail").getString("hqDefault");


             videos.add(new Video(title, id, viewCount, uploader, url, thumbUrl));
         }

         Library lib = new Library(username, videos);

         Bundle data = new Bundle();
         data.putSerializable(LIBRARY, lib);


         Message msg = Message.obtain();
         msg.setData(data);
         replyTo.sendMessage(msg);

     } catch (ClientProtocolException e) {
         Log.e("Feck", e);
     } catch (IOException e) {
         Log.e("Feck", e);
     } catch (JSONException e) {
         Log.e("Feck", e);
     }
     return null;
 }

 /* 
  * @see android.os.AsyncTask#onPostExecute(java.lang.Object)
  */
 @Override
 protected void onPostExecute(Void result) {

     //adapter.notifyDataSetChanged();
 }

 }