Android RecyclerView实现九宫格效果

package com.davis.recyclerviewdemo;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;

import com.davis.recyclerviewdemo.adapter.CommonDecoration;
import com.davis.recyclerviewdemo.adapter.RecyclerViewAdapter;
import com.davis.recyclerviewdemo.bean.MenuBean;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;
    private RecyclerViewAdapter adapter;
    private List listDatas = new ArrayList();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        init();
    }

    private void init(){
        recyclerView = (RecyclerView)findViewById(R.id.main_recycleview);
        loadMenuData();

        recyclerView.setLayoutManager(new GridLayoutManager(this, 2));
        recyclerView.addItemDecoration(new CommonDecoration(this));

        adapter = new RecyclerViewAdapter(this, listDatas);
        recyclerView.setAdapter(adapter);
    }

    private void loadMenuData(){
        listDatas.add(new MenuBean("安检", "快速安检", R.mipmap.check_blue));
        listDatas.add(new MenuBean("行李", "提醒行李动态", R.mipmap.luggage_blue));
        listDatas.add(new MenuBean("餐饮", "提供航空 餐饮美食", R.mipmap.food_blue));
        listDatas.add(new MenuBean("VIP休息", "机场休息室", R.mipmap.vip_blue));
        listDatas.add(new MenuBean("机舱服务", "机舱上网 游戏娱乐", R.mipmap.service_blue));
        listDatas.add(new MenuBean("更多", "更多信息", R.mipmap.more_blue));
    }
}

package com.davis.recyclerviewdemo.adapter;

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.view.View;

/**
 * Created by Administrator on 2019/4/14.
 */

public class CommonDecoration extends RecyclerView.ItemDecoration {
    private static final int[] ATTRS = new int[]{android.R.attr.listDivider};
    private Drawable mDivider;

    public CommonDecoration(Context context) {
        final TypedArray a = context.obtainStyledAttributes(ATTRS);
        mDivider = a.getDrawable(0);
        a.recycle();
    }

    @Override
    public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {

        drawHorizontal(c, parent);
        drawVertical(c, parent);

    }

    private int getSpanCount(RecyclerView parent) {
        // 列数
        int spanCount = -1;
        RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager) {

            spanCount = ((GridLayoutManager) layoutManager).getSpanCount();
        } else if (layoutManager instanceof StaggeredGridLayoutManager) {
            spanCount = ((StaggeredGridLayoutManager) layoutManager)
                    .getSpanCount();
        }
        return spanCount;
    }

    public void drawHorizontal(Canvas c, RecyclerView parent) {
        int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);
            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int left = child.getLeft() - params.leftMargin;
            final int right = child.getRight() + params.rightMargin
                    + mDivider.getIntrinsicWidth();
            final int top = child.getBottom() + params.bottomMargin;
            final int bottom = top + mDivider.getIntrinsicHeight();
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    public void drawVertical(Canvas c, RecyclerView parent) {
        final int childCount = parent.getChildCount();
        for (int i = 0; i < childCount; i++) {
            final View child = parent.getChildAt(i);

            final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
                    .getLayoutParams();
            final int top = child.getTop() - params.topMargin;
            final int bottom = child.getBottom() + params.bottomMargin;
            final int left = child.getRight() + params.rightMargin;
            final int right = left + mDivider.getIntrinsicWidth();

            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

    private boolean isLastColum(RecyclerView parent, int pos, int spanCount,
                                int childCount) {
        RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager) {
            // 如果是最后一列，则不需要绘制右边
            if ((pos + 1) % spanCount == 0) {
                return true;
            }
        } else if (layoutManager instanceof StaggeredGridLayoutManager) {
            int orientation = ((StaggeredGridLayoutManager) layoutManager)
                    .getOrientation();
            if (orientation == StaggeredGridLayoutManager.VERTICAL) {
                // 如果是最后一列，则不需要绘制右边
                if ((pos + 1) % spanCount == 0) {
                    return true;
                }
            } else {
                childCount = childCount - childCount % spanCount;
                if (pos >= childCount) {// 如果是最后一列，则不需要绘制右边
                    return true;
                }
            }
        }
        return false;
    }

    private boolean isLastRaw(RecyclerView parent, int pos, int spanCount, int childCount) {
        RecyclerView.LayoutManager layoutManager = parent.getLayoutManager();
        if (layoutManager instanceof GridLayoutManager) {
            int last = childCount % spanCount;
            if (last == 0) {
                last = spanCount;
            }
            childCount = childCount - last;
            if (pos >= childCount) {// 如果是最后一行，则不需要绘制底部
                return true;
            }
        } else if (layoutManager instanceof StaggeredGridLayoutManager) {
            int orientation = ((StaggeredGridLayoutManager) layoutManager)
                    .getOrientation();
            // StaggeredGridLayoutManager 且纵向滚动
            if (orientation == StaggeredGridLayoutManager.VERTICAL) {
                int last = childCount % spanCount;
                if (last == 0) {
                    last = spanCount;
                }
                childCount = childCount - last;
                // 如果是最后一行，则不需要绘制底部
                if (pos >= childCount) {
                    return true;
                }
            } else {// StaggeredGridLayoutManager 且横向滚动
                // 如果是最后一行，则不需要绘制底部
                if ((pos + 1) % spanCount == 0) {
                    return true;
                }
            }
        }
        return false;
    }

    @Override
    public void getItemOffsets(Rect outRect, int itemPosition,
                               RecyclerView parent) {
        int spanCount = getSpanCount(parent);
        int childCount = parent.getAdapter().getItemCount();

        if (isLastColum(parent, itemPosition, spanCount, childCount)) {// 如果是最后一列，则不需要绘制右边
            if (itemPosition == (childCount - 1)) {
                outRect.set(0, 0, 0, 0);
            } else {
                outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
            }
        } else if (isLastRaw(parent, itemPosition, spanCount, childCount)) {// 如果是最后一行，则不需要绘制底部
            outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
        } else {
            outRect.set(0, 0, mDivider.getIntrinsicWidth(),
                    mDivider.getIntrinsicHeight());
        }
    }
}