RecyclerView的简单使用-上

RecyclerView


一，为什么叫RecyclerView？


1，不高兴item是否在正确的位置，如何显示


用LayoutManager来显示不同的风格


2，不关心item间如何分割


ItemDecoration


3，不关注item增加与删除动画效果


ItemAnimator


4，仅仅关注如何回收与复用View




二，RecyclerView相关的重要的类


1，Adapter


2，ViewHolder


3，LayoutManager


控制RecyclerView显示的风格


4，ItemDecoration  


控制RecyclerView分割效果


5，ItemAnimator

控制RecyclerView增加与删除动画效果

Dome:

package com.example.administrator.recyclerview;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;


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

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;

    private List<String>mDatas;

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


        initDatas();
        initViews();
        //绑定适配器
        myAdapter=new SimpleAdapter(this,mDatas);
        recyclerView.setAdapter(myAdapter);
        //设置RecyclerView的布局管理
        LinearLayoutManager layoutManager=new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
        recyclerView.setLayoutManager(layoutManager);

        //设置RecyclerView的分割线
        recyclerView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));
    }
    private void initViews(){
        recyclerView= (RecyclerView) findViewById(R.id.id_recyclerView);
    }

    private void initDatas(){
        mDatas=new ArrayList<String>();
        for (int i='A'; i<='z'; i++){
            mDatas.add(""+(char)i);
        }

    }
}

主要布局:

<?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" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

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

SimpleAdapter 

package com.example.administrator.recyclerview;

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.List;

/**
 * Created by Administrator on 2016/11/8 0008.
 */
public class SimpleAdapter extends RecyclerView.Adapter<MyViewHolder> {
    private LayoutInflater layoutInflater;
    private Context context;
    private List<String>mDatas;

    SimpleAdapter(Context context, List<String> datas){
        this.context=context;
        this.mDatas=datas;
        layoutInflater=LayoutInflater.from(context);


    }
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

        View view=layoutInflater.inflate(R.layout.item_main,parent,false);
        MyViewHolder myViewHolder=new MyViewHolder(view);

        return myViewHolder;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {

        holder.tv.setText(mDatas.get(position));

    }

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



}
class MyViewHolder extends RecyclerView.ViewHolder{

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

Iitem布局:

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical"
    android:layout_width="match_parent"
    android:background="#44ff0000"
    android:layout_height="72dp">

    <TextView
        android:id="@+id/text"
        android:gravity="center"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</FrameLayout>

分割线工具类：

package com.example.administrator.recyclerview;

/*
 * Copyright (C) 2014 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.View;

/**
 * This class is from the v7 samples of the Android SDK. It's not by me!
 * <p/>分割线----工具类
 * See the license above for details.
 */
public class DividerItemDecoration extends RecyclerView.ItemDecoration
{

   private static final int[] ATTRS = new int[] { android.R.attr.listDivider };

   public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

   public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
   
   

   private Drawable mDivider;

   private int mOrientation;

   public DividerItemDecoration(Context context, int orientation)
   {
      final TypedArray a = context.obtainStyledAttributes(ATTRS);
      mDivider = a.getDrawable(0);
      a.recycle();
      setOrientation(orientation);
   }

   public void setOrientation(int orientation)
   {
      if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST)
      {
         throw new IllegalArgumentException("invalid orientation");
      }
      mOrientation = orientation;
   }

   @Override
   public void onDraw(Canvas c, RecyclerView parent)
   {

       if (mOrientation == VERTICAL_LIST) {
               drawVertical(c, parent);
           } else {
               drawHorizontal(c, parent);
           }
   }

   public void drawVertical(Canvas c, RecyclerView parent)
   {
      final int left = parent.getPaddingLeft();
      final int right = parent.getWidth() - parent.getPaddingRight();

      final int childCount = parent.getChildCount();

      for (int i = 0; i < childCount; i++)
      {
         final View child = parent.getChildAt(i);
         RecyclerView v = new RecyclerView(
               parent.getContext());
         final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
               .getLayoutParams();
         final int top = child.getBottom() + params.bottomMargin;
         final int bottom = top + mDivider.getIntrinsicHeight();
         mDivider.setBounds(left, top, right, bottom);
         mDivider.draw(c);
      }
   }

   public void drawHorizontal(Canvas c, RecyclerView parent)
   {
      final int top = parent.getPaddingTop();
      final int bottom = parent.getHeight() - parent.getPaddingBottom();

      final int childCount = parent.getChildCount();
      for (int i = 0; i < childCount; i++)
      {
         final View child = parent.getChildAt(i);
         final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child
               .getLayoutParams();
         final int left = child.getRight() + params.rightMargin;
         final int right = left + mDivider.getIntrinsicHeight();
         mDivider.setBounds(left, top, right, bottom);
         mDivider.draw(c);
      }
   }

   @Override
   public void getItemOffsets(Rect outRect, int itemPosition,
         RecyclerView parent)
   {
      if (mOrientation == VERTICAL_LIST)
      {
         outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
      } else
      {
         outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
      }
   }
}