RecycleView

一.RecycleView是什么

RecycleView是2014年谷歌大会推出的Android5.0Lollipop的一个架构，提供一个高度解耦，灵活性和高效率的体验，通过设置它提供不同的LayoutManager、ItemDecoration、ItemAnimator 可实现更加丰富多样的效果。但是RecyclerView也有缺点和 让人头疼的地方：设置列表的分割线时需要自定义，另外列表的点击事件需要自己去实现。

二.玩玩RecycleView

在build.gradle中配置

implementation ‘com.android.support:recyclerview-v7:28.0.0’

在布局中添加

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

    <android.support.v7.widget.RecyclerView
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>

添加一个实体类，模拟后台数据

public class Movie {

    public Movie(String name) {
        this.name = name;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    private String name;
}

自定义Adapter,并设置条目点击监听

package com.seven.material.recycleview;

import android.content.Context;
import android.graphics.Color;
import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;

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

/**
 * Time:2019/12/13
 * 

 * Author:wangzhou
 * 

 * Description:
 */
public class MovieAdapter extends RecyclerView.Adapter<MovieAdapter.MyHolder> {


    private Context context;
    private List<Movie> movies = new ArrayList<>();
    private LayoutInflater layoutInflater;
    private List<Integer> heights;

    public boolean isStagged() {
        return stagged;
    }

    public void setStagged(boolean stagged) {
        this.stagged = stagged;
    }

    private boolean stagged;

    public MovieAdapter(List<Movie> movies, Context context) {
        this.movies = movies;
        this.context = context;
        layoutInflater = LayoutInflater.from(context);
        heights = new ArrayList<Integer>();
        for (int i = 0; i < movies.size(); i++) {
            heights.add((int) Math.max(200,Math.random()*550));
        }
    }

    @NonNull
    @Override
    public MyHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {


        return new MyHolder(layoutInflater.inflate(R.layout.item_recy, viewGroup, false));
    }

    @Override
    public void onBindViewHolder(@NonNull MyHolder myHolder, int position) {

        myHolder.textView.setText(movies.get(position).getName());
        myHolder.itemView.setBackgroundColor(Color.rgb(100, (int) (Math.random() * 255), (int) (Math.random() * 255)));
        if(isStagged()){
            ViewGroup.LayoutParams params = myHolder.itemView.getLayoutParams();
            params.height = heights.get(position);
            myHolder.itemView.setLayoutParams(params);
        }

        myHolder.itemView.setOnClickListener(new MyClickListener(position));

    }

    @Override
    public int getItemCount() {
        return movies == null ? 0 : movies.size();
    }

    public void addItem(int i) {
        movies.add(i, new Movie("movie" + i));
        notifyItemInserted(i);
    }

    public void removeItem(int i) {
        movies.remove(i);
        notifyItemRemoved(i);
    }

    class MyHolder extends RecyclerView.ViewHolder {

        TextView textView;

        public MyHolder(@NonNull View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.txt);
        }
    }

    private ItemClickListener onItemClickListener;

    public void setItemClickListener(ItemClickListener onItemClickListener) {
        this.onItemClickListener = onItemClickListener;
    }

    public interface ItemClickListener {
        void onItemClick(View view, int position);
    }

    class MyClickListener implements View.OnClickListener {
        private int position;

        public MyClickListener(int position) {
            this.position = position;
        }

        @Override
        public void onClick(View v) {
            if (onItemClickListener != null) {
                onItemClickListener.onItemClick(v, position);
                Toast.makeText(context, "movie" + position + "被点击了！", Toast.LENGTH_SHORT).show();
            }
        }
    }
}

通过LayoutManager设置现实效果

设置线性管理器

   RecyclerView.LayoutManager linearLayoutManager =
                        new LinearLayoutManager(MainActivity.this, LinearLayoutManager.VERTICAL, false);
                movieAdapter.setStagged(true);
                recyclerView.setLayoutManager(linearLayoutManager);

设置Grid管理器

    RecyclerView.LayoutManager gridLayoutManager =
                        new GridLayoutManager(MainActivity.this, 3, LinearLayoutManager.VERTICAL, false);
                movieAdapter.setStagged(true);
                recyclerView.setLayoutManager(gridLayoutManager);

设置瀑布流

     RecyclerView.LayoutManager staggedLayoutManager = new StaggeredGridLayoutManager(3, LinearLayoutManager.VERTICAL);
                movieAdapter.setStagged(true);
                recyclerView.setLayoutManager(staggedLayoutManager);

设置分割线及添加头部和底部数据

添加交互动画

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