Android RecyclerView 多布局与混排

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多布局

这里写图片描述
关于RecyclerView的基本用法参考下面三篇博客：
Android RecyclerView之代替ListView与GridView
Android RecyclerView之添加Item分割线
Android RecyclerView 的瀑布流式布局

多布局思路：

利用Adapter的getItemViewType()方法返回不同的ViewType在onCreateViewHolder中获取不同的布局返回不同的ViewHolder（在本例子中有三种布局所以就出现了三种ViewHolder）

主要思路代码：

//返回不同的type值  @Override    public int getItemViewType(int position) {        return mList.get(position).type;    }  @Override    public MyRecycleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        MyRecycleViewHolder vh = null;        //判断viewtype类型返回不同Viewholder        switch (viewType) {            case DataModel.TYPE_APPLE:                vh = new MyRecycleViewHolderOne(mInflater.inflate(R.layout.item_one, parent,false));                break;            case DataModel.TYPE_BANANA:                vh = new MyRecycleViewHolderTwo(mInflater.inflate(R.layout.item_two, parent,false));                break;            case DataModel.TYPE_STREWBERRY:                vh = new MyRecycleViewHolderThree(mInflater.inflate(R.layout.item_three, parent,false));                break;        }        return vh;    }

完整代码展示

因为三种布局类型分别为
一：只有一个图片（水果图）
二：一个图片一个文本（水果图+水果名）
三：一个图片一个文本一个图片（水果图+水果名+Android小机器人）
item布局简单就不展示代码了。

Activity

public class MyRecyleDemo extends AppCompatActivity {    private RecyclerView mRecyclerView;    private MyRecycleAdapter mAdapter;    @Override    protected void onCreate(@Nullable Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //这里布局里面只有一个RecyclerView        setContentView(R.layout.recyclerview);        mRecyclerView= (RecyclerView) findViewById(R.id.recycler);        //为Recycler设置布局        mRecyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false));        mAdapter=new MyRecycleAdapter(this);        mRecyclerView.setAdapter(mAdapter);        //初始化数据        initData();    }    public void initData(){        List<DataModel> datas=new ArrayList<>();        //一共30个数据，三种类型，每种10个数据        for (int i=0;i<30;i++){        //前10个数据为类型一            if(i>=0&&i<10){                DataModel data=new DataModel();                data.mImg=R.mipmap.apple;                data.mName="苹果";                data.mIcon=R.mipmap.ic_launcher;                data.type=DataModel.TYPE_APPLE;                datas.add(data);            }else if(i>=10&&i<20){                DataModel data=new DataModel();                data.mImg=R.mipmap.banana;                data.mName="香蕉";                data.mIcon=R.mipmap.ic_launcher;                data.type=DataModel.TYPE_BANANA;                datas.add(data);            }else {                DataModel data=new DataModel();                data.mImg=R.mipmap.strewberry;                data.mName="草莓";                data.mIcon=R.mipmap.ic_launcher;                data.type=DataModel.TYPE_STREWBERRY;                datas.add(data);            }        }        //在adapter中添加数据        mAdapter.setData(datas);        mAdapter.notifyDataSetChanged();    }}

DataModel

public class DataModel  {    public static  final int TYPE_APPLE=1;    public static  final int TYPE_BANANA=2;    public static final int TYPE_STREWBERRY=3;    public   int mImg;    public String mName;    public int mIcon;    public int type;}

Adapter

public class MyRecycleAdapter extends RecyclerView.Adapter<MyRecycleViewHolder> {    private LayoutInflater mInflater;    private List<DataModel> mList = new ArrayList<>();    public MyRecycleAdapter(Context context) {        mInflater = LayoutInflater.from(context);    }    public void setData(List<DataModel> model) {        mList.addAll(model);    }    @Override    public MyRecycleViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        MyRecycleViewHolder vh = null;        switch (viewType) {            case DataModel.TYPE_APPLE:                vh = new MyRecycleViewHolderOne(mInflater.inflate(R.layout.item_one, parent,false));                break;            case DataModel.TYPE_BANANA:                vh = new MyRecycleViewHolderTwo(mInflater.inflate(R.layout.item_two, parent,false));                break;            case DataModel.TYPE_STREWBERRY:                vh = new MyRecycleViewHolderThree(mInflater.inflate(R.layout.item_three, parent,false));                break;        }        return vh;    }    @Override    public void onBindViewHolder(MyRecycleViewHolder holder, int position) {        holder.bindHolder(mList.get(position));    }    @Override    public int getItemViewType(int position) {        return mList.get(position).type;    }    @Override    public int getItemCount() {        return mList.size();    }}

ViewHolder

public  abstract class MyRecycleViewHolder extends RecyclerView.ViewHolder {    public ImageView mImg;    public TextView mTextView;    public ImageView mIcon;    public MyRecycleViewHolder(View itemView) {        super(itemView);    }    public abstract void bindHolder(DataModel data);}

ViewholderOne

public class MyRecycleViewHolderOne extends MyRecycleViewHolder {    public MyRecycleViewHolderOne(View itemView) {        super(itemView);        mImg = (ImageView) itemView.findViewById(R.id.fruit_img);    }    @Override    public void bindHolder(DataModel data) {        mImg.setImageResource(data.mImg);    }}

ViewHolderTwo

public  class MyRecycleViewHolderTwo extends MyRecycleViewHolder{    public MyRecycleViewHolderTwo(View itemView) {        super(itemView);        mImg = (ImageView) itemView.findViewById(R.id.fruit_img);        mTextView = (TextView) itemView.findViewById(R.id.fruit_text);    }    @Override    public void bindHolder(DataModel data) {        mImg.setImageResource(data.mImg);        mTextView.setText(data.mName);    }}

混排

未进行混排时：部分布局被压缩
这里写图片描述
进行混排，对第三种布局设置独占一行

混排思路

主要通过对GridLayoutManager 的 setSpanSizeLookup方法中的getSpanSize方法进行返回，如果你的列设置的为2，你的getSpanSize（）方法返回1则表示布局占1/2,也就是占据1列的宽度，如果返回为2则占2/2也就是占据2列宽度即1行。

主要运用代码

gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {            @Override            public int getSpanSize(int position) {              return ……;            }        });

具体代码如下：

//设置2列final GridLayoutManager gridLayoutManager=new GridLayoutManager(this,2);        gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {            @Override            public int getSpanSize(int position) {            //通过获取adapter来获取当前item的itemviewtype                int type=mRecyclerView.getAdapter().getItemViewType(position);                if (type==DataModel.TYPE_STREWBERRY){                //返回2，占一行                    return gridLayoutManager.getSpanCount();                }else {                    return 1;                }            }        });        mRecyclerView.setLayoutManager(gridLayoutManager);

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