内容：同一个RecyclerView包含多种布局。本例设置了三个不同的布局样式，都在同一个RecyclerView中展示出来。
尾末简要介绍了下GridLayoutManager的setSpanSizeLookup()方法
效果如下：

image.png

步骤：
1、定义三种不同布局，用于填充到RecyclerView中
2、加入RecyclerView控件，设置好adapter和数据
3、新建类继承RecyclerView.Adapter<RecyclerView.ViewHolder>，注意：<RecyclerView.ViewHolder>，此处不是具体的viewHoler
4、重写getItemViewType(int position)，这里设置好视图类型，后面会根据此处的返回类型去加载对应的布局
5、onCreateViewHolder(ViewGroup parent, int viewType)根据viewType填充不同布局
6、onBindViewHolder(RecyclerView.ViewHolder holder, final int position)根据holder类型设置数据填充
代码如下：
1、填充布局不贴出，就一个TextView宽高颜色不一样
2、加入RecyclerView控件，设置好adapter和数据

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/linearLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

   <android.support.v7.widget.RecyclerView
       android:id="@+id/recyclerView"
       android:layout_width="match_parent"
       android:layout_height="match_parent"/>

</LinearLayout>

public class MainActivity extends AppCompatActivity{

    private String[] mStrings = {"1", "2", "3", "3", "2", "1", "1", "3", "2", "3", "1", "3"};
    private List<String> data = new ArrayList<>();

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

        data = Arrays.asList(mStrings);
        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        recyclerView.setLayoutManager(new LinearLayoutManager(this));
        recyclerView.setAdapter(new MyAdapter(this, data));
    }
}

步骤3、4、5、6如下：

public class MyAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private Context mContext;
    private List<String> content;

    public MyAdapter(List<String> content, Context context) {
        this.content = content;
        mContext = context;
    }

    public MyAdapter(Context context, List<String> content) {
        mContext = context;
        this.content = content;
    }

    /**
     *  根据position位置(或者自己需求)设置不同视图类型
     */
    @Override
    public int getItemViewType(int position) {
        switch (content.get(position)) {
            case "1":
                return 1;
            case "2":
                return 2;
            default:
                return 3;
        }
    }

    /**
     * @param parent
     * @param viewType
     * @return 根据viewType设置不同的布局  从而实现多布局
     */
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        RecyclerView.ViewHolder viewHolder;
        View view;

        //根据不同的类型加载对应的布局
        switch (viewType) {
            case 1:
                view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_1, parent, false);
                viewHolder = new FirstHolder(view);
                return viewHolder;
            case 2:
                view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_2, parent,false);
                viewHolder = new SecondHolder(view);
                return viewHolder;
            case 3:
                view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_3, parent,false);
                viewHolder = new ThirdHolder(view);
                return viewHolder;
            default:
                return null;
        }
    }

    /**
     * @param holder
     * @param position 根据holder设置不同的数据
     */
    @Override
    public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
        if (holder instanceof FirstHolder) {
            ((FirstHolder) holder).mTextView.setText("FirstHolder");
            ((FirstHolder) holder).mTextView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    toast("FirstHolder pos:" + position);
                }
            });
        } else if (holder instanceof SecondHolder) {
            ((SecondHolder) holder).mTextView.setText("SecondHolder");
            ((SecondHolder) holder).mTextView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    toast("SecondHolder pos:" + position);
                }
            });
        }else if (holder instanceof ThirdHolder) {
            ((ThirdHolder) holder).mTextView.setText("ThirdHolder");
            ((ThirdHolder) holder).mTextView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    toast("ThirdHolder pos:" + position);
                }
            });
        }

    }

    @Override
    public int getItemCount() {
        return content.size();
    }

    private void toast(String string) {
        Toast.makeText(mContext, string, Toast.LENGTH_SHORT).show();
    }

    public static class FirstHolder extends RecyclerView.ViewHolder {
        public TextView mTextView;

        public FirstHolder(View itemView) {
            super(itemView);
            mTextView = itemView.findViewById(R.id.tv_1);
        }
    }

    public static class SecondHolder extends RecyclerView.ViewHolder{
        public TextView mTextView;

        public SecondHolder(View itemView) {
            super(itemView);
            mTextView = itemView.findViewById(R.id.tv_2);
        }
    }

    public static class ThirdHolder extends RecyclerView.ViewHolder{
        public TextView mTextView;

        public ThirdHolder(View itemView) {
            super(itemView);
            mTextView = itemView.findViewById(R.id.tv_3);
        }
    }
}

Kotlin代码如下：

class MainActivity : AppCompatActivity() {
    
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        val data = listOf<String>("1", "2", "3", "3", "2", "1", "1", "3", "2", "3", "1", "3")
        recyclerView.layoutManager = LinearLayoutManager(this)
        recyclerView.adapter = MyAdapter(this, data)
    }
}

class MyAdapter(private val context: Context, private val data: List<String>): RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    override fun getItemViewType(position: Int): Int {
        when (data[position]) {
            "1" -> return 1
            "2" -> return 2
            else -> return 3
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup?, viewType: Int): RecyclerView.ViewHolder? {
        val viewHolder: RecyclerView.ViewHolder
        val view: View

        //根据不同的类型加载对应的布局
        when (viewType) {
            1 -> {
                view = LayoutInflater.from(parent?.getContext()).inflate(R.layout.item_1, parent, false)
                viewHolder = FirstHolder(view)
                return viewHolder
            }
            2 -> {
                view = LayoutInflater.from(parent?.getContext()).inflate(R.layout.item_2, parent, false)
                viewHolder = SecondHolder(view)
                return viewHolder
            }
            3 -> {
                view = LayoutInflater.from(parent?.getContext()).inflate(R.layout.item_3, parent, false)
                viewHolder = ThirdHolder(view)
                return viewHolder
            }
            else -> return null
        }
    }


    override fun getItemCount(): Int {
        return data.size
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder?, position: Int) {
        if (holder is FirstHolder) {
            holder.mTextView.text = "FirstHolder"
            holder.mTextView.setOnClickListener { toast("FirstHolder pos:$position") }
        } else if (holder is SecondHolder) {
            holder.mTextView.text = "SecondHolder"
            holder.mTextView.setOnClickListener { toast("SecondHolder pos:$position") }
        } else if (holder is ThirdHolder) {
            holder.mTextView.text = "ThirdHolder"
            holder.mTextView.setOnClickListener { toast("ThirdHolder pos:$position") }
        }
    }

    private fun toast(string: String) {
        Toast.makeText(context, string, Toast.LENGTH_SHORT).show()
    }

    class FirstHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var mTextView: TextView

        init {
            mTextView = itemView.findViewById(R.id.tv_1)
        }
    }

    class SecondHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var mTextView: TextView

        init {
            mTextView = itemView.findViewById(R.id.tv_2)
        }
    }

    class ThirdHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var mTextView: TextView

        init {
            mTextView = itemView.findViewById(R.id.tv_3)
        }
    }
}

另一种是可以快速修改GridLayoutManager 布局 图片展示个数，通过设置setSpanSizeLookup()

image.png

代码如下：

  RecyclerView recylerview = (RecyclerView) findViewById(R.id.recylerview);
        GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 2);
        gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
            @Override
            public int getSpanSize(int i) {
                if (i == 0 || i == 3 ){
                    return 2;
                }else {
                    return 1;
                }
            }
        });
        recylerview.setLayoutManager(gridLayoutManager);
        GridAdapter adapter = new GridAdapter();
        recylerview.setAdapter(adapter);

注意：getSpanSize return 的数量不能大于 你 new GridLayoutManager(this, 2);的数量
否则会报以下错

java.lang.IllegalArgumentException: Item at position 0 requires 3 spans but GridLayoutManager has only 2 spans.