/**
* @file XListView.java
* @package me.maxwin.view
* @create Mar 18, 2012 6:28:41 PM
* @author Maxwin
* @description An ListView support (a) Pull down to refresh, (b) Pull up to load more.
* Implement IXListViewListener, and see stopRefresh() / stopLoadMore().
*/
package com.bdyjy.custom.view;
import android.content.Context;
import android.util.AttributeSet;
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;
import com.bdyjy.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.
/**
* @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);
mFooterView.show();
// init header height
mHeaderView.getViewTreeObserver().addOnGlobalLayoutListener(
new OnGlobalLayoutListener()
{
@Override
public void onGlobalLayout()
{
mHeaderViewHeight = mHeaderViewContent.getHeight();
getViewTreeObserver()
.removeGlobalOnLayoutListener(this);
}
});
}
@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);
// make sure "pull up" don't show a line in bottom when listview
// with one page
setFooterDividersEnabled(false);
} else
{
mPullLoading = false;
mFooterView.show();
mFooterView.setState(XListViewFooter.STATE_NORMAL);
// make sure "pull up" don't show a line in bottom when listview
// with one page
setFooterDividersEnabled(true);
// 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;
mFooterView.setState(XListViewFooter.STATE_NORMAL);
}
}
/**
* ���ݼ������֮��,��footer��header����ʧ
*/
public void onLoad()
{
this.stopRefresh();
this.stopLoadMore();
this.setRefreshTime("�ո�");
}
/**
* 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.
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
&& !mPullLoading)
{
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();
}
}