老婆保佑，代码无BUG

前言

本篇文章，其实很基础，也没什么难度，就是给自己查漏补缺，然后一点一点的积累，

引用

 compile 'com.android.support:recyclerview-v7:26.1.0'

一：Adapter的写法

之前记录过，请参考本篇文章


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

    private ArrayList<String> mData;

    public MyAdapter(ArrayList<String> data) {
        this.mData = data;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(R.layout.view_rv_item, parent, false);
        return new ViewHolder(v);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.mTv.setText(mData.get(position));
    }

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

    public static class ViewHolder extends RecyclerView.ViewHolder {

        TextView mTv;

        public ViewHolder(View itemView) {
            super(itemView);
            mTv = itemView.findViewById(R.id.item_tv);
        }
    }
}

二：布局管理器

1. LinearLayoutManager

线性管理器，支持横向、纵向。

（1）竖向

//竖向
mLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
//横向
mLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setAdapter(mAdapter);

LinearLayoutManager.VERTICAL

对应XML

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

    <TextView
        android:id="@+id/item_tv"
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:gravity="center"
        android:textColor="#FFF7F7F7"
        tools:text="item" />
</LinearLayout>

（2）横向

LinearLayoutManager.HORIZONTAL

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

<TextView
    android:layout_gravity="center"
    android:id="@+id/item_tv"
    android:layout_width="50dp"
    android:layout_height="match_parent"
    android:gravity="center"
    android:textColor="#FFF7F7F7"
    tools:text="item" />
</LinearLayout>

2. GridLayoutManager

网格布局管理器

mLayoutManager = new GridLayoutManager(this, 4);
mRecyclerView.setLayoutManager(mLayoutManager);

网格布局管理器

3. StaggeredGridLayoutManager

瀑布就式布局管理器

MyStageAdapter myStageAdapter = new MyStageAdapter(getData());
mLayoutManager = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);
mRecyclerView.setLayoutManager(mLayoutManager);
mRecyclerView.setAdapter(myStageAdapter);

瀑布就式布局管理器

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:layout_margin="5dp"
   android:background="@color/colorAccent">

   <TextView
       android:id="@+id/id_num"
       android:layout_width="100dp"
       android:layout_height="100dp"
       android:layout_gravity="center"
       android:gravity="center"
       android:text="1"
       android:textColor="#FFF7F7F7" />
</FrameLayout>

package com.allens.recyclerdemo;

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;

/**
 * 描述:
 * <p>
 * Created by allens on 2018/1/4.
 */

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

    private ArrayList<String> mData;
    private List<Integer> mHeights;

    public MyStageAdapter(ArrayList<String> mData) {
        this.mData = mData;
        mHeights = new ArrayList();
        for (int i = 0; i < mData.size(); i++) {
            mHeights.add((int) (100 + Math.random() * 300));
        }
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View inflate = LayoutInflater.from(parent.getContext()).inflate(R.layout.item_staggered_home, parent, false);
        return new ViewHolder(inflate);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.mTv.setText(mData.get(position));

        //设置高度
        ViewGroup.LayoutParams lp = holder.mTv.getLayoutParams();
        lp.height = mHeights.get(position);
        holder.mTv.setLayoutParams(lp);
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {

        TextView mTv;

        public ViewHolder(View itemView) {
            super(itemView);
            mTv = itemView.findViewById(R.id.id_num);
        }
    }
}

三：分割线

1. 添加Android自带的分割线

mRcv.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL));

添加Android自带的分割线

2. 自定义分割线

打开DividerItemDecoration看看它的源码

  /**
     * Sets the {@link Drawable} for this divider.
     *
     * @param drawable Drawable that should be used as a divider.
     */
    public void setDrawable(@NonNull Drawable drawable) {
        if (drawable == null) {
            throw new IllegalArgumentException("Drawable cannot be null.");
        }
        mDivider = drawable;
    }

我们只需要调用这个方法，然后传入一个Drawable对象

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">

    <gradient
        android:centerColor="#ff00ff00"
        android:endColor="#ff0000ff"
        android:startColor="#ffff0000"
        android:type="linear" />
    <size android:height="3dp" />

</shape>

 //添加自定义分割线
DividerItemDecoration divider = new DividerItemDecoration(this,DividerItemDecoration.VERTICAL);
divider.setDrawable(ContextCompat.getDrawable(this,R.drawable.rcv_divider));
mRcv.addItemDecoration(divider);

自定义分割线

当然还有一个继承ItemDecoration的方法可以实现，不过我感觉挺麻烦的，具体可以参考
张鸿洋 Android RecyclerView 使用完全解析体验艺术般的控件

这个有很多东西后期我会写一遍专门讲分割线的文章，先欠着，哈哈

四：ItemAnimator

插入删除的动画效果

mRecyclerView.setItemAnimator(new DefaultItemAnimator());