在Android ListView中使用onScroll

Question

大家好，我正在使用ListView，在滚动到底部时加载内容。但是如果快速滚动会出现错误，即同一个URL被调用多次，请问有谁能帮助我解决这个问题？我已经了解了SCROLL_STATE_IDLE，但不知道如何在我的代码中实现它。而且即使我没有触摸屏幕，它也在运行。现在我想知道如何在空闲状态下停止代码的运行。以下是我的代码。

int start = 0;
int limit = 3;
loadingMore = false;
listView.setOnScrollListener(new OnScrollListener() {

        @Override
        public void onScrollStateChanged(AbsListView view, int scrollState) {
            // TODO Auto-generated method stub
                            }

        }

        @Override
        public void onScroll(AbsListView view, int firstVisibleItem,
                int visibleItemCount, int totalItemCount) {
            // TODO Auto-generated method stub
            int lastInScreen = firstVisibleItem + visibleItemCount;


            if ((lastInScreen == totalItemCount) ) {

                if(loadingMore == false){                   
                start = lastInScreen - 1;                   
                url = "http://www.dskjhf.com/web-servic/request_response.php?type=get_articles&start="
                        + start + "&end=" + limit;
                grabURL(url);                   
            }
        }}
    });

    protected void grabURL(String url) {
    // TODO Auto-generated method stub
    new BackgroundTask().execute(url);
    loadingMore = true;
}

- Munchoo

Answer 1

检查这个，它会帮助你。对我来说，它运行良好。

        listView.setOnScrollListener(new OnScrollListener() {
            private int currentVisibleItemCount;
            private int currentScrollState;
            private int currentFirstVisibleItem;
            private int totalItem;
            private LinearLayout lBelow;


            @Override
            public void onScrollStateChanged(AbsListView view, int scrollState) {
                // TODO Auto-generated method stub
                this.currentScrollState = scrollState;
                this.isScrollCompleted();               
            }

            @Override
            public void onScroll(AbsListView view, int firstVisibleItem,
                    int visibleItemCount, int totalItemCount) {
                // TODO Auto-generated method stub
                this.currentFirstVisibleItem = firstVisibleItem;
                this.currentVisibleItemCount = visibleItemCount;
                this.totalItem = totalItemCount;


            }

            private void isScrollCompleted() {
                if (totalItem - currentFirstVisibleItem == currentVisibleItemCount
                        && this.currentScrollState == SCROLL_STATE_IDLE) {
                 /** To do code here*/

                    Page = Page + 1;
                    apiVariables = TCGAPIVariable.getSingletonObject();
                    searchUrl = apiVariables.searchList(cityId, catId, area,
                            keyword, cuisine, type, cost, "" + Page, "20",uId);
                    Log.d("SEARCH_URL", searchUrl.trim());
                    int totalRecord = Integer.parseInt(itemData.get(0)
                            .getTotalRecord());
                    if (totalRecord > totalItem) {
                        if (TCGStaticMethods
                                .isInternetAvailable(SearchActivity.this))
                            new SearchAsynTask(SearchActivity.this, searchUrl,
                                    true).execute();
                    } else {
                        LinearLayout llBelow = (LinearLayout) findViewById(R.id.pbSearchLististingBelow);
                        llBelow.setVisibility(View.GONE);
                    }
                }
            }
        });

- samsad

Answer 2

请在onScrollStateChanged方法中进行检查。

SCROLL_STATE_IDLE的值为0。

setOnScrollListener(new OnScrollListener(){
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
      // TODO Auto-generated method stub
    }
    public void onScrollStateChanged(AbsListView view, int scrollState) {
      // TODO Auto-generated method stub
      if(scrollState == 0) Log.d(TAG", "scrolling is idele...");
    }
  });

- Harsha Vardhan