ListView上下彈動（注：不包含數據的刷新）

當listview滑動到頂部和底部的時候就停住了，這時候我們想要讓listview產生上下彈動的效果但不刷新數據，通過結合晚上現有數據刷新的例子花了點時間終於做出來啦，直接拿來用就可以了  廢話不多說，上源碼：

如果需要直接引用自定義的PaddingListView就OK了

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.DecelerateInterpolator;
import android.widget.AbsListView;
import android.widget.AbsListView.OnScrollListener;
import android.widget.LinearLayout;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.Scroller;

public class PaddingListView 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
    private PaddingView mHeaderView, mFooterView;


    private int mHeaderViewHeight; // header view's height
    private boolean mEnablePullRefresh = true;
    private boolean mPullRefreshing = false; // is refreashing.
    private boolean mIsFooterReady = false;
    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
    private final static float OFFSET_RADIO = 5.0f; // support iOS like pull
    // feature.

    /**
     * @param context
     */
    public PaddingListView(Context context) {
        super(context);
        initWithContext(context);
    }

    public PaddingListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initWithContext(context);
    }

    public PaddingListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        initWithContext(context);
    }

    private void initWithContext(Context context) {
        mScroller = new Scroller(context, new DecelerateInterpolator());
        super.setOnScrollListener(this);
        mHeaderView = new PaddingView(context);
        addHeaderView(mHeaderView);
        mFooterView = new PaddingView(context);
    }
    @Override
    public void setAdapter(ListAdapter adapter) {
        if (mIsFooterReady == false) {
            mIsFooterReady = true;
            addFooterView(mFooterView);
        }
        super.setAdapter(adapter);
    }


    private void invokeOnScrolling() {
        if (mScrollListener instanceof OnXScrollListener) {
            OnXScrollListener l = (OnXScrollListener) mScrollListener;
            l.onXScrolling(this);
        }
    }

    private void updateHeaderHeight(float delta) {
        mHeaderView.setBottomMargin((int) delta
                + mHeaderView.getHeight());
        setSelection(0); // scroll to top each time
    }

    /**
     * reset header view's height.
     */
    private void resetHeaderHeight() {
        int height = mHeaderView.getHeight();
        if (height == 0) // not visible.
            return;
        if (mPullRefreshing && height <= mHeaderViewHeight) {
            return;
        }
        int finalHeight = 0; // default: scroll back to dismiss header.
        if (mPullRefreshing && height > mHeaderViewHeight) {
            finalHeight = mHeaderViewHeight;
        }
        mScrollBack = SCROLLBACK_HEADER;
        mScroller.startScroll(0, height, 0, finalHeight - height,
                SCROLL_DURATION);
        invalidate();
    }

    private void updateFooterHeight(float delta) {
        int height = mFooterView.getBottomMargin() + (int) delta;
        mFooterView.setBottomMargin(height);
    }

    private void resetFooterHeight() {
        int bottomMargin = mFooterView.getBottomMargin();
        if (bottomMargin > 0) {
            mScrollBack = SCROLLBACK_FOOTER;
            mScroller.startScroll(0, bottomMargin, 0, -bottomMargin,
                    SCROLL_DURATION);
            invalidate();
        }
    }


    @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.getHeight() > 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.getHeight() > mHeaderViewHeight) {
                        mPullRefreshing = true;
                    }
                    resetHeaderHeight();
                }
                if (getLastVisiblePosition() == mTotalItemCount - 1) {
                    // invoke load more.
                    resetFooterHeight();
                }
                break;
        }
        return super.onTouchEvent(ev);
    }

    @Override
    public void computeScroll() {
        if (mScroller.computeScrollOffset()) {
            if (mScrollBack == SCROLLBACK_HEADER) {
                mHeaderView.setBottomMargin(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);
        }
    }

    /**
     * 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);
    }

}

class PaddingView extends LinearLayout {

    private LinearLayout mContainer;


    public PaddingView(Context context) {
        super(context);
        initView(context);
    }

    public PaddingView(Context context, AttributeSet attrs) {
        super(context, attrs);
        initView(context);
    }

    public void setBottomMargin(int height) {
        if (height < 0) return;
        LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams) mContainer
                .getLayoutParams();
        lp.height = height;
        mContainer.setLayoutParams(lp);
    }

    public int getBottomMargin() {
        return mContainer.getHeight();
    }


    private void initView(Context context) {
        LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, 0);
        mContainer = new LinearLayout(context);
        addView(mContainer, lp);
    }

}