BaseAdapter教程(2) BaseAdapter的notifyDataSetChanged动态刷新

遇到了这麽一个需求，ListView滑到最底，然后会自动在底部加入新的Cell，实现动态刷新。

 

1. 首先，为ListView加上setOnScrollListener。

        lvHomePostItem.setOnScrollListener(new AbsListView.OnScrollListener() {
            private Integer scrollState;
            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
                this.scrollState = scrollState;
                switch (scrollState) {
                    // Not scrolling
                    case AbsListView.OnScrollListener.SCROLL_STATE_IDLE:
                        // go to last cell
                        if (view.getLastVisiblePosition() == (view.getCount() - 1) && totalAmountOfLvItem <= 20 ) {
                            addData();
                        }
                        break;
                }
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {}
        });

2. addData()是调用了notifyDataSetChanged。而notifyDataSetChanged是回调ListView来刷新UI，实现动态刷新。

    private Integer totalAmountOfLvItem = 0;
    private Integer getExtraNumberOfPost = 2;
    private String getHotPostByCursor;
    private String getPostResult;
    private List<PostDTO> postExtraDTOs = new ArrayList<PostDTO>();
    private ArrayList<Bitmap> bitExtraMaps = new ArrayList<Bitmap>();
    private void addData() {
        popupLoadingWindow();

        // Network thread
        new Thread(new Runnable() {
            @Override
            public void run() {

                totalAmountOfLvItem = postAdapter.getCount();

                // clear list
                if ( !postExtraDTOs.isEmpty()) {
                    postExtraDTOs.clear();
                }

                if ( !bitExtraMaps.isEmpty()) {
                    bitExtraMaps.clear();
                }

                // get extra post
                getHotPostByCursor = Configuration.getHotPostByCursor(totalAmountOfLvItem, getExtraNumberOfPost);
                getPostResult = okhttp.getResponse(getHotPostByCursor);
                postExtraDTOs = gsonTools.getPost(getPostResult);
                totalAmountOfLvItem += getExtraNumberOfPost;

                // get extra bitmap
                for ( int i = 0; i < postExtraDTOs.size(); i++ ) {
                    Bitmap temp = bitMap.returnBitMap(postExtraDTOs.get(i).getAbstractImg());
                    bitExtraMaps.add(temp);
                }

                // UI thread
                getActivity().runOnUiThread(new Runnable() {
                    @Override
                    public void run() {

                        // set extra post & bitmap into ListView Data
                        for ( int i = 0; i < postExtraDTOs.size(); i++ ) {
                            postHotDTOs.add(postExtraDTOs.get(i));
                            bitHotMaps.add(bitExtraMaps.get(i));
                        }

                        postAdapter.notifyDataSetChanged();
                        lvHomePostItem.setSelection(postAdapter.getCount()-1);

                        dismissPopupLoadingWindow();
                    }
                });

            }
        }).start();
    }

就这样实现动态刷新。