/** * @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 org.com.cctest.view;
import com.example.xlistviewtest.R;
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;
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);
// 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); } else { 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(); } }); } }
/** * 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); } }
/** * 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) { // δ����ˢ��״̬�����¼�ͷ 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) { 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(); } }
