PullToRefreshScrollView 嵌套RecyclerView实现特卖列表倒计时抢购

xiangzhihong

发布于 2018-02-05 15:05:53

1.2K0

发布于 2018-02-05 15:05:53

文章被收录于专栏：向治洪向治洪

不久之前，我们谈到了通过Handler与timer及TimerTask结合实现倒计时抢购列表，那个是PullToRefreshListView实现的，今天要讲的是PullToRefreshScrollView 嵌套RecyclerView实现的抢购首页功能，相信在很多的app中都有实现的，不过我们知道特别是这种嵌套，滑动和计算高度的时候是各种冲突的，PullToRefreshScrollView 嵌套RecyclerView会有焦点的获取问题，好，今天就实现这么一个功能。之前的功能请访问：点击打开链接

先上一张效果图：

为了方便大家的理解，我将上面的两个子模块封装成了一个组件，我们今天只对下面的实现进行讲解。

首先这里倒计时写在子线程就不说了，还有就是用RecycleView而不用ListView这也不多说了，这方面比较的文章比较多，但是我在版本5.0的时候遇到一夜问题，就是RecyclerView的高度计算不出来，这里之前面试别人的时候也说过，这里不是对RecycleView的OnMeasure（）重写，而是需要设置RecycleView的layoutManager，比如是要实现ListView的线性效果，就需要增加下面的Layoutparam.

public class WrapLinearLayoutManager extends LinearLayoutManager {

    public WrapLinearLayoutManager(Context context) {
        super(context);
    }

    public WrapLinearLayoutManager(Context context, int orientation, boolean reverseLayout) {
        super(context, orientation, reverseLayout);
    }

    private int[] mMeasuredDimension = new int[2];

    @Override
    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state,
                          int widthSpec, int heightSpec) {

        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);

        int width = 0;
        int height = 0;
        for (int i = 0; i < getItemCount(); i++) {
            measureScrapChild(recycler, i,
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    mMeasuredDimension);

            if (getOrientation() == HORIZONTAL) {
                width = width + mMeasuredDimension[0];
                if (i == 0) {
                    height = mMeasuredDimension[1];
                }
            } else {
                height = height + mMeasuredDimension[1];
                if (i == 0) {
                    width = mMeasuredDimension[0];
                }
            }
        }
        switch (widthMode) {
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        switch (heightMode) {
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
            case View.MeasureSpec.AT_MOST:
            case View.MeasureSpec.UNSPECIFIED:
        }

        setMeasuredDimension(width, height);
    }

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
                                   int heightSpec, int[] measuredDimension) {
        try {
            View view = recycler.getViewForPosition(0);//fix 动态添加时报IndexOutOfBoundsException

            if (view != null) {
                RecyclerView.LayoutParams p = (RecyclerView.LayoutParams) view.getLayoutParams();

                int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec,
                        getPaddingLeft() + getPaddingRight(), p.width);

                int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec,
                        getPaddingTop() + getPaddingBottom(), p.height);

                view.measure(childWidthSpec, childHeightSpec);
                measuredDimension[0] = view.getMeasuredWidth() + p.leftMargin + p.rightMargin;
                measuredDimension[1] = view.getMeasuredHeight() + p.bottomMargin + p.topMargin;
                recycler.recycleView(view);
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
        }
    }

    @Override
    public boolean canScrollVertically() {
        return false;
    }
}

如果是要实现Grid的效果，需要设置，这个GridLayoutManager系统帮我们实现了

public class WrapGridLayoutManager extends GridLayoutManager {
    private int mwidth = 0;
    private int mheight = 0;
 
    public WrapGridLayoutManager(Context context, int spanCount) {
        super(context, spanCount);
    }
 
    public WrapGridLayoutManager((Context context, int spanCount,
            int orientation, boolean reverseLayout) {
        super(context, spanCount, orientation, reverseLayout);
    }
 
    private int[] mMeasuredDimension = new int[2];
 
    public int getMwidth() {
        return mwidth;
    }
 
    public void setMwidth(int mwidth) {
        this.mwidth = mwidth;
    }
 
    public int getMheight() {
        return mheight;
    }
 
    public void setMheight(int mheight) {
        this.mheight = mheight;
    }
 
    @Override
    public void onMeasure(RecyclerView.Recycler recycler,
            RecyclerView.State state, int widthSpec, int heightSpec) {
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);
 
        int width = 0;
        int height = 0;
        int count = getItemCount();
        int span = getSpanCount();
        for (int i = 0; i < count; i++) {
            measureScrapChild(recycler, i, View.MeasureSpec.makeMeasureSpec(i,
                    View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(i,
                            View.MeasureSpec.UNSPECIFIED), mMeasuredDimension);
 
            if (getOrientation() == HORIZONTAL) {
                if (i % span == 0) {
                    width = width + mMeasuredDimension[0];
                }
                if (i == 0) {
                    height = mMeasuredDimension[1];
                }
            } else {
                if (i % span == 0) {
                    height = height + mMeasuredDimension[1];
                }
                if (i == 0) {
                    width = mMeasuredDimension[0];
                }
            }
        }
 
        switch (widthMode) {
        case View.MeasureSpec.EXACTLY:
            width = widthSize;
        case View.MeasureSpec.AT_MOST:
        case View.MeasureSpec.UNSPECIFIED:
        }
 
        switch (heightMode) {
        case View.MeasureSpec.EXACTLY:
            height = heightSize;
        case View.MeasureSpec.AT_MOST:
        case View.MeasureSpec.UNSPECIFIED:
        }
        setMheight(height);
        setMwidth(width);
        setMeasuredDimension(width, height);
    }
 
    private void measureScrapChild(RecyclerView.Recycler recycler,
            int position, int widthSpec, int heightSpec, int[] measuredDimension) {
        if (position < getItemCount()) {
            try {
                View view = recycler.getViewForPosition(0);// fix
                                                            // 鍔ㄦ?佹坊鍔犳椂鎶ndexOutOfBoundsException
                if (view != null) {
                    this.measureChild(view, 0, 0);
                    measuredDimension[0] = this.getDecoratedMeasuredWidth(view);
                    measuredDimension[1] = this.getDecoratedMeasuredHeight(view);
                    recycler.recycleView(view);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }
     
    public static class SpacesItemDecoration extends RecyclerView.ItemDecoration {
          private int space;
 
          public SpacesItemDecoration(int space) {
            this.space = space;
          }
 
          @Override
          public void getItemOffsets(Rect outRect, View view, 
              RecyclerView parent, RecyclerView.State state) {
            outRect.left = space;
            outRect.right = space;
            outRect.bottom = space;
            outRect.top = space;
 
            // Add top margin only for the first item to avoid double space between items
//          if(parent.getChildLayoutPosition(view) == 0)
          }
        }
}

recyclerView.setLayoutManager(new GridLayoutManager(getActivity(), 2));

要解决PullToRefreshScrollView和RecyclerView我尝试了，通过OnIntercetor事件拦截，不起作用，最后只需要在RecycleView设置下面一段话就好了。

 LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity(), LinearLayoutManager.VERTICAL, false) {
            @Override
            public boolean canScrollVertically() {
                return false;
            }
        };
        recyclerView.setLayoutManager(linearLayoutManager);

最后附上代码的下载地址点击打开链接，欢迎留言（加群：278792776）

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原始发表：2016-11-05 ，如有侵权请联系 cloudcommunity@tencent.com 删除

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PullToRefreshScrollView 嵌套RecyclerView实现特卖列表倒计时抢购

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