android-如何在GridView的最后一项之后添加页脚ProgressBar

概述这是我的代码.数据不足时,它将加载更多数据.我想在加载更多数据时向GridView添加页脚ProgressBar.怎么做？我在StackOverflow上看到了很多问题,但没有答案.publicclassMainActivityextendsActivity{privatestaticfinalStringTAG="MainActivity";privatefinal

这是我的代码.数据不足时,它将加载更多数据.我想在加载更多数据时向GrIDVIEw添加页脚Progressbar.怎么做？我在StackOverflow上看到了很多问题,但没有答案.

public class MainActivity extends Activity {    private static final String TAG = "MainActivity";    private final List<Integer> commonImageList = new ArrayList<Integer>();    private int index = 0;    private boolean isLoading = false;    private static final int NUM = 18;    private ImageAdapter adapter;    @OverrIDe    public voID onCreate(final Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentVIEw(R.layout.activity_main);        final Task task = new Task(mThumbIDs, index);        task.setonPostExecuteListener(new OnPostExecuteListener<List<Integer>>() {            @OverrIDe            public voID onPostExecute(final List<Integer> result) {                System.out.println("RESulT: " + result);                if(result.isEmpty()) {                    return;                }                // Store it.                commonImageList.addAll(result);                // Prepare grIDVIEw.                final GrIDVIEw grIDvIEw = (GrIDVIEw) findVIEwByID(R.ID.grIDvIEw);                adapter = new ImageAdapter(MainActivity.this, commonImageList);                grIDvIEw.setAdapter(adapter);                grIDvIEw.setonScrollListener(new OnScrollListener() {                    @OverrIDe                    public voID onScrollStateChanged(final AbsListVIEw vIEw, final int scrollState) {                    }                    @OverrIDe                    public voID onScroll(final AbsListVIEw vIEw, final int firstVisibleItem,                            final int visibleItemCount, final int totalitemCount) {                        System.out.println("firstVisibleItem: " + firstVisibleItem);                        System.out.println("visibleItemCount: " + visibleItemCount);                        System.out.println("totalitemCount: " + totalitemCount);                        final boolean loadMore = (firstVisibleItem + visibleItemCount >= totalitemCount);                        System.out.println("loadMore: " + loadMore);                        System.out.println("isLoading: " + isLoading);                        if(loadMore && !isLoading) {                            // Todo Show footer here.                            ShowLog.showLogInfo(TAG, "============= LOAD MORE =============");                            // Get more images.                            index = index + NUM;                            final Task task = new Task(mThumbIDs, index);                            task.setonPreExecuteListener(new OnPreExecuteListener() {                                @OverrIDe                                public voID onPreExecute() {                                    isLoading = true;                                }                            });                            task.setonPostExecuteListener(new OnPostExecuteListener<List<Integer>>() {                                @OverrIDe                                public voID onPostExecute(final List<Integer> result) {                                    System.out.println("RESulT222: " + result);                                    if(result.isEmpty()) {                                        return;                                    }                                    System.out.println("HIEU THONG MINH");                                    // Update common List.                                    commonImageList.addAll(result);                                    // Update adapter.                                    adapter.notifyDataSetChanged();                                    isLoading = false;                                }                            });                            task.execute();                        }                    }                });            }        });        task.execute();    }    private class Task extends AbstractWorkerTask<VoID, VoID, List<Integer>> {        private final Integer []thumbs;        private final int index;        public Task(final Integer []thumbs, final int index) {            this.thumbs = thumbs;            this.index = index;        }        @OverrIDe        protected List<Integer> doInBackground(final VoID... params) {            final List<Integer> List = new ArrayList<Integer>();            for(int i = index; i < index + NUM && i < thumbs.length; ++i) {                List.add(thumbs[i]);            }            return List;        }    }    public static class ImageAdapter extends BaseAdapter {        private final Context context;                      private final List<Integer> imageList;        public ImageAdapter(final Context c, final List<Integer> imageList) {            context = c;            this.imageList = imageList;        }        @OverrIDe        public int getCount() {            return imageList.size();        }        @OverrIDe        public Object getItem(final int position) {            return null;        }        @OverrIDe        public long getItemID(final int position) {            return 0;        }        // create a new ImageVIEw for each item referenced by the Adapter        @OverrIDe        public VIEw getVIEw(final int position, final VIEw convertVIEw, final VIEwGroup parent) {            ImageVIEw imageVIEw;            if (convertVIEw == null) {  // if it's not recycled, initialize some attributes                imageVIEw = new ImageVIEw(context);                imageVIEw.setLayoutParams(new GrIDVIEw.LayoutParams(150, 150));                imageVIEw.setScaleType(ImageVIEw.ScaleType.CENTER_CROP);                imageVIEw.setpadding(8, 8, 8, 8);            } else {                imageVIEw = (ImageVIEw) convertVIEw;            }            imageVIEw.setimageResource(imageList.get(position));            return imageVIEw;        }    }    // references to our images    private static final Integer[] mThumbIDs = {            R.drawable.sample_2, R.drawable.sample_3,            R.drawable.sample_4, R.drawable.sample_5,            R.drawable.sample_6, R.drawable.sample_7,            R.drawable.sample_0, R.drawable.sample_1,            R.drawable.sample_2, R.drawable.sample_3,            R.drawable.sample_4, R.drawable.sample_5,            R.drawable.sample_6, R.drawable.sample_7,            R.drawable.sample_0, R.drawable.sample_1,            R.drawable.sample_2, R.drawable.sample_3,            R.drawable.sample_4, R.drawable.sample_5,            R.drawable.sample_6, R.drawable.sample_7,            R.drawable.sample_0, R.drawable.sample_1,            R.drawable.sample_2, R.drawable.sample_3,            R.drawable.sample_4, R.drawable.sample_5,            R.drawable.sample_6, R.drawable.sample_7,            R.drawable.sample_0, R.drawable.sample_1,            R.drawable.sample_2, R.drawable.sample_3,            R.drawable.sample_4, R.drawable.sample_5,    };}

activity_main.xml

<?xml version="1.0" enCoding="utf-8"?><GrIDVIEw xmlns:androID="http://schemas.androID.com/apk/res/androID"     androID:ID="@+ID/grIDvIEw"    androID:layout_wIDth="fill_parent"     androID:layout_height="fill_parent"    androID:columnWIDth="150dp"    androID:numColumns="3"    androID:verticalSpacing="10dp"    androID:horizontalSpacing="10dp"    androID:stretchMode="columnWIDth"    androID:gravity="center"/>

解决方法:

这是我在GrIDVIEw中添加加载更多项目的逻辑
1.在适配器的输入数据的最后创建一个伪造的物品

public class MediaGrIDAdapter extends BaseAdapter {    private ArrayList<Media> List;    private final Media special = new Media("-1", "", "", "", "");     public MediaGrIDAdapter(Context context, int imageID, ArrayList<Media> array, int type) {        List = array;        if(List != null) {            List.add(special);        }            }public voID appendDataList(ArrayList<Media> appendedList, boolean isEnd) { //called in postExecute to append new data    //remove special element in original List    List.remove(List.size() - 1);    //append collection of media to List    List.addAll(appendedList);    //check to add special element    if(!isEnd) {        List.add(special);    }}   }

2.在getVIEw方法中：检查它是否是最后一个位置(是我们的假货),为此返回特殊布局(进度条…).

    if(position == (List.size() - 1)) {        Context context = parent.getContext();        item = (relativeLayout) LayoutInflater.from(context).inflate(R.layout.item_special_more, null);        item.setTag(MORE_button);        return item;    }

最后一个onItemClick检查标记以启动getMoreAsyncTask

if (v.getTag().equals(MediaGrIDAdapter.MORE_button)) {                            GetMoreItems task = new GetMoreItems();                        task.execute(url);                        return;                    }

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