/**
 * Created by lzy on 2017/6/6 0006.
 */
public class MySwipeRefreshLayout extends SwipeRefreshLayout{
    private final TextView mFooterView;
    ListView view;
    OnListScrollListener listener;
    boolean isLoading;//判斷當前layout是否在載入中，防止非同步操作導致載入中再重複載入
boolean isShowing;//判斷底部載入欄是否需要顯示
Context mContext;
    public 
 
MySwipeRefreshLayout(Context context) {
        super(context);
        mContext = context;
        mFooterView = new TextView(mContext);
        mFooterView.setText("正在載入中");
        mFooterView.setGravity(Gravity.CENTER);
        mFooterView.setTextSize(22);
    }

    public MySwipeRefreshLayout(Context context, AttributeSet attrs) {
        super
 
(context, attrs);
        mContext = context;
        mFooterView = new TextView(mContext);
        mFooterView.setText("正在載入中");
        mFooterView.setGravity(Gravity.CENTER);
        mFooterView.setTextSize(22);
    }

    @Override
protected void onLayout(boolean changed, int left, int top, int 
 
right, int bottom) {
        super.onLayout(changed, left, top, right, bottom);
        if(view ==null){
            if(getChildAt(0)instanceof ListView){
                view = (ListView)getChildAt(0);
            }
        }
    }
    /**
     * 在分發事件的時候處理子控制元件的觸控事件
     *
     * @param ev
* @return
*/
private float mDownY, mUpY, lastFloat ;
    @Override
public boolean dispatchTouchEvent(MotionEvent ev) {

        switch (ev.getAction()) {
            case MotionEvent.ACTION_DOWN:
                // 移動的起點
mDownY = ev.getY();
                break;
            case MotionEvent.ACTION_MOVE:
                float mMoveY = ev.getY();
                // 移動過程中判斷時候能上拉載入更多
if (isLoadMore()&&!isShowing&&lastFloat>mMoveY+5) {
                    // 載入資料
setShowing(true);
                }
                lastFloat = mMoveY;
                break;
            case MotionEvent.ACTION_UP:
                // 移動的終點
mUpY = getY();
                if (isShowing) {
                    // 載入資料
if(listener!=null){
                        isLoading = true;
                        listener.Refresh();
                    }
                }
                lastFloat = 0;
                break;
        }
        return super.dispatchTouchEvent(ev);
    }
    /**
     * 設定載入狀態，是否載入傳入boolean值進行判斷
     *
     * @param showing
*/
public void setShowing(boolean showing) {
        isShowing = showing;
        if (isShowing) {
            // 顯示佈局
view.addFooterView(mFooterView);
        } else {
            // 隱藏佈局
view.removeFooterView(mFooterView);

            // 重置滑動的座標
mDownY = 0;
            mUpY = 0;
            isLoading = showing;
        }
    }

    private synchronized boolean isLoadMore() {
        boolean isLast = view.getLastVisiblePosition() == view.getAdapter().getCount()-1;
        return isLast&&!isLoading;
    }
    public void setOnListScrollListener(OnListScrollListener listener){
        this.listener = listener;
    }
    public interface OnListScrollListener{
        void Refresh();
    }
}