XlistView: A listview which can pull to refresh and load more (1)
/**
* @file XListView.java
* @package me.maxwin.view
* @create 2013/5/13
* @author youxiachai
* @description An ListView support (a) Pull down to refresh, (b) Pull up to load more.
* Implement IXListViewListener, and see stopRefresh() / stopLoadMore().
*
*/
import android.content.Context;
import android.content.SharedPreferences;
import android.os.AsyncTask;
import android.preference.PreferenceManager;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.view.animation.DecelerateInterpolator;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.RelativeLayout;
import android.widget.Scroller;
import android.widget.TextView;
public class XListView extends ListView implements OnScrollListener {
public static final long ONE_MINUTE = 60 * 1000;
public static final long ONE_HOUR = 60 * ONE_MINUTE;
public static final long ONE_DAY = 24 * ONE_HOUR;
public static final long ONE_MONTH = 30 * ONE_DAY;
public static final long ONE_YEAR = 12 * ONE_MONTH;
protected long lastUpdateTime;
protected float mLastY = -1; // save event y
protected Scroller mScroller; // used for scroll back
protected OnScrollListener mScrollListener; // user's scroll listener
// the interface to trigger refresh and load more.
protected IXListViewLoadMore mLoadMore;
protected IXListViewRefreshListener mOnRefresh;
private SharedPreferences preferences;
private String RefreshTimeTag="XListViewRefreshTime";
// -- header view
protected XListViewHeader mHeaderView;
// header view content, use it to calculate the Header's height. And hide it
// when disable pull refresh.
protected RelativeLayout mHeaderViewContent;
protected TextView mHeaderTimeView;
protected int mHeaderViewHeight; // header view's height
protected boolean mEnablePullRefresh = true;
protected boolean mPullRefreshing = false; // is refreashing.
// -- footer view
protected XListViewFooter mFooterView;
protected boolean mEnablePullLoad;
protected boolean mPullLoading;
protected boolean mIsFooterReady = false;
// total list items, used to detect is at the bottom of listview.
protected int mTotalItemCount;
// for mScroller, scroll back from header or footer.
protected int mScrollBack;
protected final static int SCROLLBACK_HEADER = 0;
protected final static int SCROLLBACK_FOOTER = 1;
protected final static int SCROLL_DURATION = 400; // scroll back duration
protected final static int PULL_LOAD_MORE_DELTA = 50; // when pull up >=
// 50px
// at bottom,
// trigger
// load more.
protected final static float OFFSET_RADIO = 1.8f; // support iOS like pull
// feature.
/**
* @param context
*/
public XListView(Context context) {
super(context);
initWithContext(context);
}
public XListView(Context context, AttributeSet attrs) {
super(context, attrs);
initWithContext(context);
}
public XListView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
initWithContext(context);
}
protected void initWithContext(Context context) {
mScroller = new Scroller(context, new DecelerateInterpolator());
// XListView need the scroll event, and it will dispatch the event to
// user's listener (as a proxy).
super.setOnScrollListener(this);
preferences = PreferenceManager.getDefaultSharedPreferences(context);
// init header view
mHeaderView = new XListViewHeader(context);
mHeaderViewContent = (RelativeLayout) mHeaderView
.findViewById(R.id.xlistview_header_content);
mHeaderTimeView = (TextView) mHeaderView
.findViewById(R.id.xlistview_header_time);
//mHeaderTimeView.setText(refreshUpdatedAtValue());
addHeaderView(mHeaderView);
// init footer view
mFooterView = new XListViewFooter(context);
// init header height
mHeaderView.getViewTreeObserver().addOnGlobalLayoutListener(
new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
mHeaderViewHeight = mHeaderViewContent.getHeight();
getViewTreeObserver()
.removeGlobalOnLayoutListener(this);
}
});
disablePullLoad();
disablePullRefreash();
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
// make sure XListViewFooter is the last footer view, and only add once.
if (mIsFooterReady == false) {
// if not inflate screen ,footerview not add
if(getAdapter() != null){
if (getLastVisiblePosition() != (getAdapter().getCount() - 1)) {
mIsFooterReady = true;
addFooterView(mFooterView);
}
}
}
}
@Override
public void setAdapter(ListAdapter adapter) {
super.setAdapter(adapter);
}
/**
* enable or disable pull down refresh feature.
*
* @param enable
*/
public void setPullRefreshEnable(IXListViewRefreshListener refreshListener) {
mEnablePullRefresh = true;
mHeaderViewContent.setVisibility(View.VISIBLE);
this.mOnRefresh = refreshListener;
}
public void disablePullRefreash() {
mEnablePullRefresh = false;
// disable, hide the content
mHeaderViewContent.setVisibility(View.INVISIBLE);
}
/**
* enable or disable pull up load more feature.
*
* @param enable
*/
public void setPullLoadEnable(IXListViewLoadMore loadMoreListener) {
mEnablePullLoad = true;
this.mLoadMore = loadMoreListener;
mPullLoading = false;
mFooterView.show();
mFooterView.setState(XListViewFooter.STATE_NORMAL);
// both "pull up" and "click" will invoke load more.
mFooterView.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
startLoadMore();
}
});
}
public void disablePullLoad() {
mEnablePullLoad = false;
mFooterView.hide();
mFooterView.setOnClickListener(null);
}
/**
* stop refresh, reset header view.
*/
public void stopRefresh() {
if (mPullRefreshing == true) {
mPullRefreshing = false;
preferences.edit()
.putLong(RefreshTimeTag, System.currentTimeMillis()).commit();
mHeaderTimeView.setText(refreshUpdatedAtValue());
resetHeaderHeight();
}
}
/**
* Get the time gap between now and last refresh time
* @return time string
*/
private String refreshUpdatedAtValue() {
lastUpdateTime = preferences.getLong(RefreshTimeTag, -1);
long currentTime = System.currentTimeMillis();
long timePassed = currentTime - lastUpdateTime;
long timeIntoFormat;
String updateAtValue;
if (lastUpdateTime == -1) {
updateAtValue = getResources().getString(R.string.not_updated_yet);
} else if (timePassed < 0) {
updateAtValue = getResources().getString(R.string.time_error);
} else if (timePassed < ONE_MINUTE) {
updateAtValue = getResources().getString(R.string.updated_just_now);
} else if (timePassed < ONE_HOUR) {
timeIntoFormat = timePassed / ONE_MINUTE;
updateAtValue = timeIntoFormat + "MINS";
} else if (timePassed < ONE_DAY) {
timeIntoFormat = timePassed / ONE_HOUR;
updateAtValue = timeIntoFormat + "HOURS";
} else if (timePassed < ONE_MONTH) {
timeIntoFormat = timePassed / ONE_DAY;
updateAtValue = timeIntoFormat + "DAYS";
} else if (timePassed < ONE_YEAR) {
timeIntoFormat = timePassed / ONE_MONTH;
updateAtValue = timeIntoFormat + "MONTHS";
} else {
timeIntoFormat = timePassed / ONE_YEAR;
updateAtValue = timeIntoFormat + "YEARS";
}
return updateAtValue;
}
/**
* stop load more, reset footer view.
*/
public void stopLoadMore() {
if (mPullLoading == true) {
mPullLoading = false;
mFooterView.setState(XListViewFooter.STATE_NORMAL);
}
}
/**
* set last refresh time
*
* @param time
*/
public void setRefreshTime(String time) {
}
protected void invokeOnScrolling() {
if (mScrollListener instanceof IXScrollListener) {
IXScrollListener l = (IXScrollListener) mScrollListener;
l.onXScrolling(this);
}
}
protected void updateHeaderHeight(float delta) {
mHeaderView.setVisiableHeight((int) delta
+ mHeaderView.getVisiableHeight());
if (mEnablePullRefresh && !mPullRefreshing) { // 未处于刷新状态,更新箭头
if (mHeaderView.getVisiableHeight() > mHeaderViewHeight) {
mHeaderView.setState(XListViewHeader.STATE_READY);
} else {
mHeaderView.setState(XListViewHeader.STATE_NORMAL);
}
}
setSelection(0); // scroll to top each time
}
/**
* reset header view's height.
*/
protected void resetHeaderHeight() {
int height = mHeaderView.getVisiableHeight();
if (height == 0) // not visible.
return;
// refreshing and header isn't shown fully. do nothing.
if (mPullRefreshing && height <= mHeaderViewHeight) {
return;
}
int finalHeight = 0; // default: scroll back to dismiss header.
// is refreshing, just scroll back to show all the header.
if (mPullRefreshing && height > mHeaderViewHeight) {
finalHeight = mHeaderViewHeight;
}
Log.d("xlistview", "resetHeaderHeight-->" + (finalHeight - height));
mScrollBack = SCROLLBACK_HEADER;
mScroller.startScroll(0, height, 0, finalHeight - height,
SCROLL_DURATION);
// trigger computeScroll
invalidate();
}
protected void resetHeaderHeight(int disy) {
int height = mHeaderView.getVisiableHeight();
if (height == 0) // not visible.
return;
// refreshing and header isn't shown fully. do nothing.
if (mPullRefreshing && height <= mHeaderViewHeight) {
return;
}
int finalHeight = 0; // default: scroll back to dismiss header.
// is refreshing, just scroll back to show all the header.
if (mPullRefreshing && height > mHeaderViewHeight) {
finalHeight = mHeaderViewHeight;
}
mScrollBack = SCROLLBACK_HEADER;
Log.d("xlistview", "resetHeaderHeight-->" + (finalHeight - height));
mScroller.startScroll(0, height, 0, finalHeight - height + 100,
SCROLL_DURATION);
// trigger computeScroll
invalidate();
}
protected void updateFooterHeight(float delta) {
int height = mFooterView.getBottomMargin() + (int) delta;
if (mEnablePullLoad && !mPullLoading) {
if (height > PULL_LOAD_MORE_DELTA) { // height enough to invoke load
// more.
mFooterView.setState(XListViewFooter.STATE_READY);
} else {
mFooterView.setState(XListViewFooter.STATE_NORMAL);
}
}
mFooterView.setBottomMargin(height);
// setSelection(mTotalItemCount - 1); // scroll to bottom
}
protected void resetFooterHeight() {
int bottomMargin = mFooterView.getBottomMargin();
if (bottomMargin > 0) {
mScrollBack = SCROLLBACK_FOOTER;
mScroller.startScroll(0, bottomMargin, 0, -bottomMargin,
SCROLL_DURATION);
invalidate();
}
}
protected void startLoadMore() {
if (mEnablePullLoad
&& mFooterView.getBottomMargin() > PULL_LOAD_MORE_DELTA
&& !mPullLoading) {
mPullLoading = true;
mFooterView.setState(XListViewFooter.STATE_LOADING);
if (mLoadMore != null) {
AsynLoadMoreTask asynLoadMoreTask =new AsynLoadMoreTask();
asynLoadMoreTask.execute();
}
}
}
//Async Task for loading more data;
private class AsynLoadMoreTask extends AsyncTask<Void,Void,Void>
{
@Override
protected Void doInBackground(Void... params) {
mLoadMore.onLoadMore();
return null;
}
@Override
protected void onPostExecute(Void result) {
stopLoadMore();
super.onPostExecute(result);
}
}
@Override
public boolean onTouchEvent(MotionEvent ev) {
if (mLastY == -1) {
mLastY = ev.getRawY();
}
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
mLastY = ev.getRawY();
break;
case MotionEvent.ACTION_MOVE:
final float deltaY = ev.getRawY() - mLastY;
mLastY = ev.getRawY();
//Log.d("xlistview", "xlistView-height");
if (getFirstVisiblePosition() == 0
&& (mHeaderView.getVisiableHeight() > 0 || deltaY > 0)
&& !mPullRefreshing) {
// the first item is showing, header has shown or pull down.
if(mEnablePullRefresh){
updateHeaderHeight(deltaY / OFFSET_RADIO);
invokeOnScrolling();
}
} else if (getLastVisiblePosition() == mTotalItemCount - 1
&& (mFooterView.getBottomMargin() > 0 || deltaY < 0)
&& !mPullLoading) {
// last item, already pulled up or want to pull up.
if(mEnablePullLoad){
updateFooterHeight(-deltaY / OFFSET_RADIO);
}
}
break;
default:
mLastY = -1; // reset
if (getFirstVisiblePosition() == 0) {
// invoke refresh
startOnRefresh();
resetHeaderHeight();
} else if (getLastVisiblePosition() == mTotalItemCount - 1) {
// invoke load more.
startLoadMore();
resetFooterHeight();
}
break;
}
return super.onTouchEvent(ev);
}
protected void startOnRefresh() {
if (mEnablePullRefresh
&& mHeaderView.getVisiableHeight() > mHeaderViewHeight
&& !mPullRefreshing) {
mPullRefreshing = true;
mHeaderView.setState(XListViewHeader.STATE_REFRESHING);
if (mOnRefresh != null) {
AsyncRefreshTask asyncRefreshTask =new AsyncRefreshTask();
asyncRefreshTask.execute();
}
}
}
//AsyncTask for refresh Data
private class AsyncRefreshTask extends AsyncTask<Void, Void, Void>
{
@Override
protected Void doInBackground(Void... params) {
mOnRefresh.onRefresh();
return null;
}
@Override
protected void onPostExecute(Void result) {
stopRefresh();
super.onPostExecute(result);
}
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
if (mScrollBack == SCROLLBACK_HEADER) {
mHeaderView.setVisiableHeight(mScroller.getCurrY());
} else {
mFooterView.setBottomMargin(mScroller.getCurrY());
}
postInvalidate();
invokeOnScrolling();
}
super.computeScroll();
}
@Override
public void setOnScrollListener(OnScrollListener l) {
mScrollListener = l;
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
if (mScrollListener != null) {
mScrollListener.onScrollStateChanged(view, scrollState);
}
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
// send to user's listener
mTotalItemCount = totalItemCount;
if (mScrollListener != null) {
mScrollListener.onScroll(view, firstVisibleItem, visibleItemCount,
totalItemCount);
}
}
}
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great
Sorry, but what is it for? I do not understand.
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