package com.jiuqi.ui.widget;
/**
* @file XListView.java
* @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.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.view.WindowManager;
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;
import com.jqyd.uilib.R;
public class XListView extends ListView implements OnScrollListener{
private float mLastY = -1; // save event y
private Scroller mScroller; // used for scroll back
private OnScrollListener mScrollListener; // user's scroll listener
// the interface to trigger refresh and load more.
private IXListViewListener mListViewListener;
// -- header view
private XListViewHeader mHeaderView;
// header view content, use it to calculate the Header's height. And hide it
// when disable pull refresh.
private RelativeLayout mHeaderViewContent;
private TextView mHeaderTimeView;
private int mHeaderViewHeight; // header view's height
private boolean mEnablePullRefresh = true;
private boolean mPullRefreshing = false; // is refreashing.
// -- footer view
private XListViewFooter mFooterView;
private boolean mEnablePullLoad;
private boolean mPullLoading;
private boolean mIsFooterReady = false;
// total list items, used to detect is at the bottom of listview.
private int mTotalItemCount;
// for mScroller, scroll back from header or footer.
private int mScrollBack;
private final static int SCROLLBACK_HEADER = 0;
private final static int SCROLLBACK_FOOTER = 1;
private final static int SCROLL_DURATION = 400; // scroll back duration
private final static int PULL_LOAD_MORE_DELTA = 50; // when pull up >= 50px
// at bottom, trigger
// load more.
private final static float OFFSET_RADIO = 1.8f; // support iOS like pull
// feature.
private static float SCREEN_HEIGHT;
private boolean mHaslistData = true;
private boolean listIsNull = true;
public void setmHaslistData(boolean mHaslistData) {
this.mHaslistData = mHaslistData;
}
public void setListIsNull(boolean listIsNull) {
this.listIsNull = listIsNull;
}
/**
* @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);
}
private 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);
// 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);
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);
}
});
WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
SCREEN_HEIGHT = wm.getDefaultDisplay().getHeight();
}
@Override
public void setAdapter(ListAdapter adapter){
// make sure XListViewFooter is the last footer view, and only add once.
if(mIsFooterReady == false){
mIsFooterReady = true;
addFooterView(mFooterView);
}
super.setAdapter(adapter);
}
/**
* enable or disable pull down refresh feature.
*
* @param enable
*/
public void setPullRefreshEnable(boolean enable){
mEnablePullRefresh = enable;
if(!mEnablePullRefresh){ // disable, hide the content
mHeaderViewContent.setVisibility(View.INVISIBLE);
}
else{
mHeaderViewContent.setVisibility(View.VISIBLE);
}
}
/**
* enable or disable pull up load more feature.
*
* @param enable
*/
public void setPullLoadEnable(boolean enable){
mEnablePullLoad = enable;
if(!mEnablePullLoad){
mFooterView.hide();
mFooterView.setOnClickListener(null);
}
else{
mPullLoading = false;
mFooterView.show();
if(mHaslistData){
mFooterView.setState(XListViewFooter.STATE_NORMAL);
}else{
mFooterView.setState(XListViewFooter.STATE_NULLDATA);
}
// both "pull up" and "click" will invoke load more.
mFooterView.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v){
startLoadMore();
}
});
}
}
/**
* stop refresh, reset header view.
*/
public void stopRefresh(){
if(mPullRefreshing == true){
mPullRefreshing = false;
resetHeaderHeight();
}
}
/**
* stop load more, reset footer view.
*/
public void stopLoadMore(){
if(mPullLoading == true){
mPullLoading = false;
}
setFooterview("");
}
public void stopLoadMore(String showMsg){
if(mPullLoading == true){
mPullLoading = false;
}
setFooterview(showMsg);
}
public void setFooterview(String showMsg){
if(mHaslistData){
mFooterView.setState(XListViewFooter.STATE_NORMAL,showMsg);
}else{
if(listIsNull){
mFooterView.setState(XListViewFooter.STATE_NULLDATA,showMsg);
}else {
mFooterView.setState(XListViewFooter.STATE_NULLMOREDATA,showMsg);
}
}
}
public void showNoData(){
setFooterview("");
}
public void showNoData(String msg){
setFooterview(msg);
}
/**
* set last refresh time
*
* @param time
*/
public void setRefreshTime(String time){
mHeaderTimeView.setText(time);
}
private void invokeOnScrolling(){
if(mScrollListener instanceof OnXScrollListener){
OnXScrollListener l = (OnXScrollListener)mScrollListener;
l.onXScrolling(this);
}
}
private 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.
*/
private 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;
}
mScrollBack = SCROLLBACK_HEADER;
mScroller.startScroll(0, height, 0, finalHeight - height, SCROLL_DURATION);
// trigger computeScroll
invalidate();
}
private 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
}
private void resetFooterHeight(){
int bottomMargin = mFooterView.getBottomMargin();
if(bottomMargin > 0){
mScrollBack = SCROLLBACK_FOOTER;
mScroller.startScroll(0, bottomMargin, 0, -bottomMargin, SCROLL_DURATION);
invalidate();
}
}
private void startLoadMore(){
mPullLoading = true;
mFooterView.setState(XListViewFooter.STATE_LOADING);
if(mListViewListener != null){
mListViewListener.onLoadMore();
}
}
@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();
if(getFirstVisiblePosition() == 0 && (mHeaderView.getVisiableHeight() > 0 || deltaY > 0)){
// the first item is showing, header has shown or pull down.
updateHeaderHeight(deltaY / OFFSET_RADIO);
invokeOnScrolling();
}
else if(getLastVisiblePosition() == mTotalItemCount - 1
&& (mFooterView.getBottomMargin() > 0 || deltaY < 0))
{
// last item, already pulled up or want to pull up.
//如果列表的长度大于屏幕的高度,才去加载更多数据
if(getFirstVisiblePosition() != 0){
updateFooterHeight(-deltaY / OFFSET_RADIO);
}
}
break;
default:
mLastY = -1; // reset
if(getFirstVisiblePosition() == 0){
// invoke refresh
if(mEnablePullRefresh && mHeaderView.getVisiableHeight() > mHeaderViewHeight){
mPullRefreshing = true;
mHeaderView.setState(XListViewHeader.STATE_REFRESHING);
if(mListViewListener != null){
mListViewListener.onRefresh();
}
}
resetHeaderHeight();
}
else if(getLastVisiblePosition() == mTotalItemCount - 1){
// invoke load more.
if(mEnablePullLoad && mFooterView.getBottomMargin() > PULL_LOAD_MORE_DELTA){
startLoadMore();
}
resetFooterHeight();
}
break;
}
return super.onTouchEvent(ev);
}
@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);
}
}
public void setXListViewListener(IXListViewListener l){
mListViewListener = l;
}
/**
* you can listen ListView.OnScrollListener or this one. it will invoke
* onXScrolling when header/footer scroll back.
*/
public interface OnXScrollListener extends OnScrollListener{
public void onXScrolling(View view);
}
/**
* implements this interface to get refresh/load more event.
*/
public interface IXListViewListener {
public void onRefresh();
public void onLoadMore();
}
}