XListView

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package com.example.day_13demo1.view;import android.content.Context;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import android.view.ViewTreeObserver;import android.view.animation.DecelerateInterpolator;import android.widget.AbsListView;import android.widget.ListAdapter;import android.widget.ListView;import android.widget.RelativeLayout;import android.widget.Scroller;import android.widget.TextView;import com.example.day_13demo1.R;/** * Created by dell on 2017/10/14. */public class XListView extends ListView implements AbsListView.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 ViewTreeObserver.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);        }    }    /**     * 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();    }}
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