Android project: Use the pulltorefresh open-source project extension to pull more processing methods from the pull-down refresh and listen for listview scrolling.

Many android applications use the pulltorefresh open-source project for pull-down refresh. However, its scalability has some limitations when pulling and loading more resources. I checked a lot and found that this open-source project does not support pull-down refresh and pull-up loading at the same time. This component has a mode attribute, which can be set to both, that is, both upper and lower can be pulled. However, if you only set this attribute, the pull-up and pull-down operations will have the same effect. Therefore, to use this open-source project to pull down and refresh and load more resources, you need to perform some processing in the code.

====================================== Pulltorefresh ======================================

Open-source projects:Android-PullToRefresh

Project address: https://github.com/chrisbanes/Android-PullToRefresh/wiki/Quick-Start-Guide

1. properties: https://github.com/chrisbanes/Android-PullToRefresh/blob/master/library/res/values/attrs.xml

Namespace: xmlns: ptr = "http://schemas.android.com/apk/res-auto"

Ptr: ptrAnimationStyle	The animation effect provides two values: flip and rotate. The default value is rotate.
Ptr: ptrRefreshableViewBackground	Set the background color of the refreshed View.
Ptr: ptrHeaderBackground	Set the background color of the header View.
Ptr: ptrHeaderTextColor	Set the color of the View text in the header
Ptr: ptrHeaderSubTextColor	Set the color of the header view subtitle text
Ptr: ptrMode	PullFromStart: PullFromEnd: Both;

2. Common Methods

SetOnRefreshListener (OnRefreshListener listener): sets the refresh listener;

SetOnLastItemVisibleListener (OnLastItemVisibleListener listener): sets whether the listener goes to the bottom;

SetOnPullEventListener (OnPullEventListener); sets the event listener;

OnRefreshComplete (): Set to refresh complete

=================================================================== ======================================

The key to changing to pull-up loading is to determine the scrolling direction of the listview before the onrefresh method is executed. The following method is the best one in the tried method. It cannot be a perfect solution, but it should be the most effective one. (When the number of rows on the first screen is not full, or the scroll distance of the first line is smaller than the Row Height, there may still be some error. However, the list of most applications can be filled with screens on every page, and the method can be improved based on other gestures ).

int mLastFirstVisibleItem = 0;boolean mIsScrollingUp;@Overridepublic void onScrollStateChanged(AbsListView view, int scrollState){                                                                                                         if (view.getId() == mListView.getId())    {        final int currentFirstVisibleItem = mListView.getFirstVisiblePosition();                                                                                                                 if (currentFirstVisibleItem > mLastFirstVisibleItem)        {            mIsUp = true;        }        else if (currentFirstVisibleItem < mLastFirstVisibleItem)        {            mIsUp = false;        }        mLastFirstVisibleItem = currentFirstVisibleItem;    }                                                                                                     }

References: http://stackoverflow.com/questions/12114963/detecting-the-scrolling-direction-in-the-adapter-up-down/12115157#12115157

====================================== Implement pull-down refresh and pull-up loading more ====== ====================================

After the json Parsing is completed, determine whether to pull up or pull down and refresh:

// Parse jsonprivate void parseJson (String result) {List <ListJson> localList = parseJsonArray (Utils. parseListJson (result, "key"); if (! MIsUp) {mDataList. clear ();} mDataList. addAll (localList );}

After the data is loaded, yydatasetchanged and the PullRefreshListView are notified, and the page number is added to 1:

// Private void loadComplete () {mPullRefreshListView. onRefreshComplete (); mAdapter. policydatasetchanged (); mPage + = 1 ;}

Determine the pull-up and drop-down directions, listen to refresh the listview, and modify the text description of the header and the bottom view:

/********************* Process pull-down refresh and pull-up listening ******** **************** // refresh the listview listener @ Overridepublic void onRefresh (PullToRefreshBase <ListView> refreshView) {// obtain the refresh time. Set the refresh time format to String str = DateUtils. formatDateTime (getActivity (), System. currentTimeMillis (), DateUtils. FORMAT_NUMERIC_DATE | DateUtils. FORMAT_NO_NOON); // determines whether to pull the drop-down list or if (! MIsUp) mPage = 0; // set the refresh text description (during refreshing) if (mIsUp) {mPullRefreshListView. getLoadingLayoutProxy (). setRefreshingLabel ("loading"); mPullRefreshListView. getLoadingLayoutProxy (). setPullLabel ("pull up to load more"); mPullRefreshListView. getLoadingLayoutProxy (). setReleaseLabel ("Release starts loading"); refreshView. getLoadingLayoutProxy (). setLastUpdatedLabel ("last loading time:" + str);} else {mPullRefreshListView. getLoadingLayoutProxy (). setRefreshingLabel ("refreshing"); mPullRefreshListView. getLoadingLayoutProxy (). setPullLabel ("pull-down refresh"); mPullRefreshListView. getLoadingLayoutProxy (). setReleaseLabel ("Release starts refreshing"); refreshView. getLoadingLayoutProxy (). setLastUpdatedLabel ("Last Update time:" + str) ;}// start the download task and load the data loadTask () ;}int mLastFirstVisibleItem = 0; boolean mIsScrollingUp; @ Overridepublic void onScrollStateChanged (AbsListView view, int scrollState) {if (view. getId () = mListView. getId () {final int currentFirstVisibleItem = mListView. getFirstVisiblePosition (); if (currentFirstVisibleItem> mLastFirstVisibleItem) {mIsUp = true;} else if (currentFirstVisibleItem <strong) {mIsUp = false;} Then = currentFirstVisibleItem ;}} @ Overridepublic void onScroll (AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {// set the text description for refreshing (before expanding the refresh column) if (mIsUp) {mPullRefreshListView. getLoadingLayoutProxy (). setRefreshingLabel ("loading"); mPullRefreshListView. getLoadingLayoutProxy (). setPullLabel ("pull up to load more"); mPullRefreshListView. getLoadingLayoutProxy (). setReleaseLabel ("Release starts loading");} else {mPullRefreshListView. getLoadingLayoutProxy (). setRefreshingLabel ("refreshing"); mPullRefreshListView. getLoadingLayoutProxy (). setPullLabel ("pull-down refresh"); mPullRefreshListView. getLoadingLayoutProxy (). setReleaseLabel ("Release start refresh") ;}@ Overridepublic void onLastItemVisible () {mIsUp = true ;}

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