RecyclerView實現的瀑布流效果

具體介紹見:  使用RecyclerView實現ListView,GridView的效果(上下,左右滑動)

MainActivity:

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DefaultItemAnimator;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.util.Log;
import android.view.View;

import java.util.ArrayList;

/**
 * 再循環視圖,內部實現了復用
 */
public class MainActivity extends AppCompatActivity {

    /**
     * 復用視圖的控件
     */
    private RecyclerView recyclerView;

    /**
     * 顯示的數據
     */
    private ArrayList<String> mDatas;

    /**
     * RecyclerView的適配器
     */
    private MyRecyclerViewAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //1.找到控件
        recyclerView = (RecyclerView) findViewById(R.id.recyclerview);
        //2.聲名為瀑布流的布局方式: 3列,垂直方向
        StaggeredGridLayoutManager staggeredGridLayoutManager = new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);
        //3.為recyclerView設置布局管理器
        recyclerView.setLayoutManager(staggeredGridLayoutManager);
        initData();//初始化數據
        //3.創建適配器
        adapter = new MyRecyclerViewAdapter(this, mDatas);
        //設置添加,移除item的動畫,DefaultItemAnimator為默認的
        recyclerView.setItemAnimator(new DefaultItemAnimator());
        //4.設置適配器
        recyclerView.setAdapter(adapter);

        //添加點擊事件
        adapter.setOnItemClickListener(new MyRecyclerViewAdapter.OnRecyclerItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                //Toast.makeText(MainActivity.this,"單擊了:"+mDatas.get(position),Toast.LENGTH_SHORT).show();
                adapter.addItem(position,"添加的內容");
                Log.i("tag", "onItemClick: "+position);
                Log.i("tag", "集合: "+mDatas.toString());
            }
        });
        //設置長按事件
        adapter.setOnItemLongClickListener(new MyRecyclerViewAdapter.onRecyclerItemLongClickListener() {
            @Override
            public void onItemLongClick(View view, int position) {
                //Toast.makeText(MainActivity.this,"長按了:"+mDatas.get(position),Toast.LENGTH_SHORT).show();
                adapter.removeItem(position);
                Log.i("tag", "onItemLongClick: "+position);
                Log.i("tag", "集合: "+mDatas.toString());
            }
        });

    }

    //初始化數據
    protected void initData(){
        mDatas = new ArrayList<String>();
        for (int i = 'A'; i < 'z'; i++){
            mDatas.add("" + (char) i);
        }
    }

}

適配器,MyRecyclerViewAdapter

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

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

/**
 * 實現瀑布流效果的適配器
 */
public class MyRecyclerViewAdapter extends RecyclerView.Adapter<MyRecyclerViewAdapter.MyViewHolder> {

    private Context context;
    private List<String> list;//數據
    private List<Integer> heightList;//裝產出的隨機數

    private OnRecyclerItemClickListener mOnItemClickListener;//單擊事件
    private onRecyclerItemLongClickListener mOnItemLongClickListener;//長按事件


    public MyRecyclerViewAdapter(Context context, List<String> list) {
        this.context = context;
        this.list = list;
        //記錄為每個控件產生的隨機高度,避免滑回到頂部出現空白
        heightList = new ArrayList<>();
        for (int i = 0; i < list.size(); i++) {
            int height = new Random().nextInt(200) + 100;//[100,300)的隨機數
            heightList.add(height);
        }
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //找到item的布局
        View view= LayoutInflater.from(context).inflate(R.layout.recycler_item_layout,parent,false);
        return new MyViewHolder(view);//將布局設置給holder
    }

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

    /**
     * 綁定視圖到holder,就如同ListView的getView(),但是這里已經把復用實現了,我們只需要填充數據就行.
     * 由於在復用的時候都是調用該方法填充數據,但是上滑的時候,又會隨機產生高度設置到控件上,這樣當滑
     * 到頂部可能就會看到一片空白,因為后面隨機產生的高度和之前的高度不一樣,就不能填充屏幕了,所以
     * 需要記錄每個控件產生的隨機高度,然后在復用的時候再設置上去 */
    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        //填充數據
        holder.textView.setText(list.get(position)+"");
        //由於需要實現瀑布流的效果,所以就需要動態的改變控件的高度了
        ViewGroup.LayoutParams params = holder.textView.getLayoutParams();
        params.height=heightList.get(position);
        holder.textView.setLayoutParams(params);

        //設置單擊事件
        if(mOnItemClickListener !=null){
               holder.textView.setOnClickListener(new View.OnClickListener() {
                   @Override
                   public void onClick(View v) {
                       //這里是為textView設置了單擊事件,回調出去
                       //mOnItemClickListener.onItemClick(v,position);這里需要獲取布局中的position,不然亂序
                       mOnItemClickListener.onItemClick(v,holder.getLayoutPosition());
                   }
               });
        }
        //長按事件
        if(mOnItemLongClickListener != null){
            holder.textView.setOnLongClickListener(new View.OnLongClickListener() {
                @Override
                public boolean onLongClick(View v) {
                    //回調出去
                    mOnItemLongClickListener.onItemLongClick(v,holder.getLayoutPosition());
                    return true;//不返回true,松手還會去執行單擊事件
                }
            });
        }
    }

    class MyViewHolder extends RecyclerView.ViewHolder{

        TextView textView;

        public MyViewHolder(View itemView) {
            super(itemView);
            textView = (TextView) itemView.findViewById(R.id.textView);
        }
    }

    /**
     * 處理item的點擊事件,因為recycler沒有提供單擊事件,所以只能自己寫了
     */
    interface OnRecyclerItemClickListener {
        public void onItemClick(View view, int position);
    }

    /**
     * 長按事件
     */
    interface  onRecyclerItemLongClickListener{
        public void onItemLongClick(View view, int position);
    }

    /**
     * 暴露給外面的設置單擊事件
     */
    public void setOnItemClickListener(OnRecyclerItemClickListener onItemClickListener){
        mOnItemClickListener = onItemClickListener;
    }

    /**
     * 暴露給外面的長按事件
     */
    public void setOnItemLongClickListener(onRecyclerItemLongClickListener onItemLongClickListener){
        mOnItemLongClickListener = onItemLongClickListener;
    }

    /**
     * 向指定位置添加元素
     */
    public void addItem(int position, String value) {
        if(position > list.size()) {
            position = list.size();
        }
        if(position < 0) {
            position = 0;
        }
        /**
         * 使用notifyItemInserted/notifyItemRemoved會有動畫效果
         * 而使用notifyDataSetChanged()則沒有
         */
        list.add(position, value);//在集合中添加這條數據
        heightList.add(position,new Random().nextInt(200) + 100);//添加一個隨機高度,會在onBindViewHolder方法中得到設置
        notifyItemInserted(position);//通知插入了數據
    }

    /**
     * 移除指定位置元素
     */
    public String removeItem(int position) {
        if(position > list.size()-1) {
            return null;
        }
        heightList.remove(position);//刪除添加的高度
        String value = list.remove(position);//所以還需要手動在集合中刪除一次
        notifyItemRemoved(position);//通知刪除了數據,但是沒有刪除list集合中的數據
        return value;
    }

}

主布局,activity_main.xml:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.workspace.my.recyclerviewtest.MainActivity">

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

Item布局文件,recycler_item_layout.xml

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

    <TextView
        android:id="@+id/textView"
        android:textSize="30sp"
        android:gravity="center"
        android:layout_margin="3dp"
        android:background="#ffcccc"
        android:layout_width="match_parent"
        android:layout_height="200dp" />

</LinearLayout>

效果如下: