RecyclerView和ScrollView嵌套使用

我们的recyclerView有多个layoutmanager，通过重写layoutmanager的方法就可以让recyclerView和ScrollView嵌套了。但是请注意，如果recyclerView很长那么强烈不建议去做嵌套，因为这样recyclerView会在展示的时候立刻展示所有内容，效率极低。

本文的两部分代码来自一个博主的博客，另一个是我自己写的，正好可以完全适用于现有的layoutmanager。大家需要的话可以试试，应该问题不大。

原博主的demo：https://github.com/Frank-Zhu/AndroidRecyclerViewDemo

1.LinearLayoutManager和ScrollView嵌套

package com.frankzhu.recyclerviewdemo;

import android.content.Context;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;
import android.view.ViewGroup;

/**
 * Author:    ZhuWenWu
 * Version    V1.0
 * Date:      2015/2/26  14:15.
 * Description:
 * Modification  History:
 * Date             Author                Version            Description
 * -----------------------------------------------------------------------------------
 * 2015/2/26        ZhuWenWu            1.0                    1.0
 * Why & What is modified:
 */
public class FullyLinearLayoutManager extends LinearLayoutManager {

    private static final String TAG = FullyLinearLayoutManager.class.getSimpleName();

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

    public FullyLinearLayoutManager(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);

        Log.i(TAG, "onMeasure called. 
widthMode " + widthMode
                + " 
heightMode " + heightSpec
                + " 
widthSize " + widthSize
                + " 
heightSize " + heightSize
                + " 
getItemCount() " + getItemCount());

        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 {
        }
    }
}

2.GridLayoutManager和ScrollView进行嵌套

package com.frankzhu.recyclerviewdemo;

import android.content.Context;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.view.ViewGroup;

/**
 * Author:    ZhuWenWu
 * Version    V1.0
 * Date:      2015/2/26  14:14.
 * Description:
 * Modification  History:
 * Date             Author                Version            Description
 * -----------------------------------------------------------------------------------
 * 2015/2/26        ZhuWenWu            1.0                    1.0
 * Why & What is modified:
 */
public class FullyGridLayoutManager extends GridLayoutManager {
    public FullyGridLayoutManager(Context context, int spanCount) {
        super(context, spanCount);
    }

    public FullyGridLayoutManager(Context context, int spanCount, int orientation, boolean reverseLayout) {
        super(context, spanCount, 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;
        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:
        }

        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 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();
            }
        }
    }
}

3.StaggeredGridLayoutManager和ScrollView进行嵌套

package com.kale.waterfalldemo.extra.RecyclerView;

import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;
import android.view.ViewGroup;

/**
 * @author Jack Tony
 * @brief 不规则排列（类似于瀑布流）的布局管理器
 * @date 2015/4/6
 */
public class ExStaggeredGridLayoutManager extends StaggeredGridLayoutManager {

    public ExStaggeredGridLayoutManager(int spanCount, int orientation) {
        super(spanCount, orientation);
    }

    // 尺寸的数组，[0]是宽，[1]是高
    private int[] measuredDimension = new int[2];

    // 用来比较同行/列那个item罪宽/高
    private int[] dimension;


    @Override

    public void onMeasure(RecyclerView.Recycler recycler, RecyclerView.State state, int widthSpec, int heightSpec) {
        // 宽的mode+size
        final int widthMode = View.MeasureSpec.getMode(widthSpec);
        final int widthSize = View.MeasureSpec.getSize(widthSpec);
        // 高的mode + size
        final int heightMode = View.MeasureSpec.getMode(heightSpec);
        final int heightSize = View.MeasureSpec.getSize(heightSpec);

        // 自身宽高的初始值
        int width = 0;
        int height = 0;
        // item的数目
        int count = getItemCount();
        // item的列数
        int span = getSpanCount();
        // 根据行数或列数来创建数组
        dimension = new int[span];

        for (int i = 0; i < count; i++) {
            measureScrapChild(recycler, i,
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED),
                    View.MeasureSpec.makeMeasureSpec(i, View.MeasureSpec.UNSPECIFIED), measuredDimension);

           // 如果是竖直的列表，计算item的高，否则计算宽度
            //Log.d("LISTENER", "position " + i + " height = " + measuredDimension[1]);
            if (getOrientation() == VERTICAL) {
                dimension[findMinIndex(dimension)] += measuredDimension[1];
            } else {
                dimension[findMinIndex(dimension)] += measuredDimension[0];
            }
        }
        if (getOrientation() == VERTICAL) {
            height = findMax(dimension);
        } else {
            width = findMax(dimension);
        }
        

        switch (widthMode) {
            // 当控件宽是match_parent时，宽度就是父控件的宽度
            case View.MeasureSpec.EXACTLY:
                width = widthSize;
                break;
            case View.MeasureSpec.AT_MOST:
                break;
            case View.MeasureSpec.UNSPECIFIED:
                break;
        }
        switch (heightMode) {
            // 当控件高是match_parent时，高度就是父控件的高度
            case View.MeasureSpec.EXACTLY:
                height = heightSize;
                break;
            case View.MeasureSpec.AT_MOST:
                break;
            case View.MeasureSpec.UNSPECIFIED:
                break;
        }
        // 设置测量尺寸  
        setMeasuredDimension(width, height);
    }

    private void measureScrapChild(RecyclerView.Recycler recycler, int position, int widthSpec,
            int heightSpec, int[] measuredDimension) {

        // 挨个遍历所有item
        if (position < getItemCount()) {
            try {
                View view = recycler.getViewForPosition(position);//fix 动态添加时报IndexOutOfBoundsException

                if (view != null) {
                    RecyclerView.LayoutParams lp = (RecyclerView.LayoutParams) view.getLayoutParams();
                    int childWidthSpec = ViewGroup.getChildMeasureSpec(widthSpec, getPaddingLeft() + getPaddingRight(), lp.width);
                    int childHeightSpec = ViewGroup.getChildMeasureSpec(heightSpec, getPaddingTop() + getPaddingBottom(), lp.height);
                    // 子view进行测量，然后可以通过getMeasuredWidth()获得测量的宽，高类似
                    view.measure(childWidthSpec, childHeightSpec);
                    // 将item的宽高放入数组中
                    measuredDimension[0] = view.getMeasuredWidth() + lp.leftMargin + lp.rightMargin;
                    measuredDimension[1] = view.getMeasuredHeight() + lp.topMargin + lp.bottomMargin;
                    recycler.recycleView(view);
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    private int findMax(int[] array) {
        int max = array[0];
        for (int value : array) {
            if (value > max) {
                max = value;
            }
        }
        return max;
    }

    /**
     * 得到最数组中最小元素的下标
     *
     * @param array
     * @return
     */
    private int findMinIndex(int[] array) {
        int index = 0;
        int min = array[0];
        for (int i = 0; i < array.length; i++) {
            if (array[i] < min) {
                min = array[i];
                index = i;
            }
        }
        return index;
    }
   
}