gridview控件增删改查(安卓v7支持包下的ListView替代品————RecyclerView)

RecyclerView这个控件也出来很久了，相信大家也学习的差不多了，如果还没学习的，或许我可以带领大家体验一把这个艺术般的控件。

据官方介绍，该控件是属于之间用的非常多的ListView和GridView的替代品，既然能替代用的如此普遍的它们，这自然有其该有的优势。

1）相对于ListView而言RecyclerView的优势体现在：

①封装了之前ListView的优化，封装了之前ViewHolder的复用，这样在自定义适配器的时候我们面向的不再是View，而是一个ViewHolder.

②提供了插板式的体验，高度解耦，异常灵活，针对每一项的显示抽取出了相应的类来控制每一个item的显示。若想实现网格视图或者瀑布流或者横向的ListView都可以通过制定不一样的LayoutManager来实现高大上的效果，这样就可以针对自己的业务逻辑随意发挥了。

③现在的RecyclerView对增删也有了动画的加入，并且你还可以自定义这些动画。

④对于Adaper适配器，现在刷新也增加了相应的方法，虽然之前的notifyDataSetChanged同样可以实现这样的效果，但是每次刷新整个界面在数据多的时候必然会大大影响用户体验。所以Adapter增加了更新数据的方法notifyItemInserted和notifyItemRemoved，这样就可以在增删数据的时候只刷新被操作的Item,而且还加入了高大上的动画效果呢。

2）基本用法：

相信描述了这么多，你一定对这个神奇的控件迫不及待想尝试一波了。要用到这个RecyclerView很简单，首先在Gradle中添加支持包：

compile 'com.android.support:recyclerview-v7:24.0.0'

下面就先来一个简单的用法，首先来Activity

package com.example.nanchen.recyclerviewdemo;r r import android.os.Bundle;r import android.support.v7.app.AppCompatActivity;r import android.support.v7.widget.DefaultItemAnimator;r import android.support.v7.widget.LinearLayoutManager;r import android.support.v7.widget.RecyclerView;r import android.view.View;r import android.widget.Toast;r r import java.util.ArrayList;r import java.util.List;r import java.util.Locale;r r public class MainActivity extends AppCompatActivity implements MyAdapter.OnRecyclerItemClickListener {r r private MyAdapter adapter;r r @Overrider protected void onCreate(Bundle savedInstanceState) {r super.onCreate(savedInstanceState);r setContentView(R.layout.activity_main);r r RecyclerView recyclerView = (RecyclerView) findViewById(R.id.main_recycler);r List<String> list = new ArrayList<>;r for (int i = 0; i < 100; i++) {r // list.add(String.format(Locale.CHINA, "第%03d条数据%s", i, i % 2 == 0 ? "" : "-----------------------"));r list.add(String.format(Locale.CHINA, "第%03d条数据", i));r }r adapter = new MyAdapter(this, list);r adapter.setOnRecyclerItemClickListener(this);r recyclerView.setAdapter(adapter);r r DefaultItemAnimator animator = new DefaultItemAnimator;r animator.setRemoveDuration(1000);r recyclerView.setItemAnimator(animator);r //recyclerView.addItemDecoration(new MyDividerItemDecoration(this,MyDividerItemDecoration.VERTICAL_LIST));r r //最后一个参数是反转布局一定是false,为true的时候为逆向显示，在聊天记录中可能会有使用r //这个东西在显示后才会加载，不会像ScollView一样一次性加载导致内存溢出r LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);r recyclerView.setLayoutManager(layoutManager);r r // GridLayoutManager gridLayoutManager = new GridLayoutManager(this, 3);r // gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup {r // @Overrider // public int getSpanSize(int position) {r // if (position == 0){r // return 3;r // }r // return 1;r // }r // });r // recyclerView.setLayoutManager(gridLayoutManager);r r // StaggeredGridLayoutManager staggeredGridLayoutManager = new StaggeredGridLayoutManager(3, StaggeredGridLayoutManager.VERTICAL);r // recyclerView.setLayoutManager(staggeredGridLayoutManager);r }r r @Overrider public void OnRecyclerItemClick(RecyclerView parent, View view, int position, String data) {r Toast.makeText(this, data, Toast.LENGTH_SHORT).show;r adapter.remove(position);r }r }r

在上面的Activity代码中，可见，我们需要自己指定LayoutManager，代码中用的是LinearLayoutMagener，你可以试试其他的。

再看看Adapter,有一个对大多数人来说很悲催的是，我们的ListView中一定会有的点击事件，而RecyclerView并没有提供这样的方法，这些点击事件都是需要我们自己学的，我这里Adapter就简单的实现了下，点击就会删除该Item。

package com.example.nanchen.recyclerviewdemo;r r import android.content.Context;r import android.support.v7.widget.RecyclerView;r import android.view.LayoutInflater;r import android.view.View;r import android.view.ViewGroup;r import android.widget.TextView;r r import java.util.List;r r /**r * 自定义RecyclerView的Adapterr * Created by 南尘 on 16-7-15.r */r public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> implements View.OnClickListener {r r private Context context;r private List<String> list;r private OnRecyclerItemClickListener listener;r private RecyclerView recyclerView;r r public void setOnRecyclerItemClickListener(OnRecyclerItemClickListener listener) {r this.listener = listener;r }r r public MyAdapter(Context context, List<String> list) {r this.context = context;r this.list = list;r }r r //在为RecyclerView提供数据的时候调用r @Overrider public void onAttachedToRecyclerView(RecyclerView recyclerView) {r super.onAttachedToRecyclerView(recyclerView);r this.recyclerView = recyclerView;r }r r @Overrider public void onDetachedFromRecyclerView(RecyclerView recyclerView) {r super.onDetachedFromRecyclerView(recyclerView);r this.recyclerView = null;r }r r @Overrider public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {r View view = LayoutInflater.from(context).inflate(R.layout.item,parent,false);r view.setOnClickListener(this);r return new ViewHolder(view);r }r r @Overrider public void onBindViewHolder(ViewHolder holder, int position) {r holder.text.setText(list.get(position));r }r r @Overrider public int getItemCount {r return list.size;r }r r @Overrider public void onClick(View v) {r if (recyclerView != null && listener != null){r int position = recyclerView.getChildAdapterPosition(v);r listener.OnRecyclerItemClick(recyclerView,v,position,list.get(position));r }r }r r /**r * 删除指定数据r * @param position 数据位置r */r public void remove(int position){r list.remove(position);r // notifyDataSetChanged;r notifyItemRemoved(position);//这样就只会删除这一条数据，而不会一直刷r r }r r /**r * 插入数据r * @param position 插入位置r * @param data 插入的数据r */r public void insert(int position,String data){r list.add(position,data);r notifyItemInserted(position);r r }r r public static class ViewHolder extends RecyclerView.ViewHolder{r r private final TextView text;r r public ViewHolder(View itemView) {r super(itemView);r text = (TextView) itemView.findViewById(R.id.item_text);r }r }r r r /**r * 自定义RecyclerView的点击事件r */r interface OnRecyclerItemClickListener{r void OnRecyclerItemClick(RecyclerView parent,View view,int position,String data);r }r r }r

继承这个Adapter需要指定一个ViewHolder的泛型，当然这个ViewHolder通常是由我们作为一个静态类自己写的。其他这个就像我们之前ListView中的BaseAdapter一样。

自己还可以实现其他的点击事件。

下面看下Xml，第一个是主布局，第二个是每一个项的布局，我这里就简单只实现一个TextView了。

<?xml version="1.0" encoding="utf-8"?>r <RelativeLayoutr xmlns:android="http://schemas.android.com/apk/res/android"r xmlns:tools="http://schemas.android.com/tools"r xmlns:app="http://schemas.android.com/apk/res-auto"r android:layout_width="match_parent"r android:layout_height="match_parent"r tools:context="com.example.nanchen.recyclerviewdemo.MainActivity">r r <android.support.v7.widget.RecyclerViewr android:layout_width="match_parent"r android:layout_height="match_parent"r android:id="@+id/main_recycler"/>r r </RelativeLayout>r

<?xml version="1.0" encoding="utf-8"?>r <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"r android:layout_width="match_parent"r android:layout_height="wrap_content"r android:orientation="vertical">r r <TextViewr android:id="@+id/item_text"r android:textSize="30sp"r android:layout_width="match_parent"r android:layout_height="match_parent"/>r </LinearLayout>r

这样运行出来你估计就会看到没有分割线，那么分割线怎么弄呢，看下文档，需要我们自己去写，这个网上有很多。

上一个我看到过很多次的。

package com.example.nanchen.recyclerviewdemo;r r import android.content.Context;r import android.content.res.TypedArray;r import android.graphics.Canvas;r import android.graphics.Rect;r import android.graphics.drawable.Drawable;r import android.support.v7.widget.LinearLayoutManager;r import android.support.v7.widget.RecyclerView;r import android.view.View;r r /**r * Created by 南尘 on 16-7-15.r */r public class MyDividerItemDecoration extends RecyclerView.ItemDecoration {r private static final int ATTRS = new int{r android.R.attr. listDividerr };r r public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;r r public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;r r private Drawable mDivider;r r private int mOrientation;r r public MyDividerItemDecoration(Context context, int orientation) {r final TypedArray a = context.obtainStyledAttributes(ATTRS );r mDivider = a.getDrawable(0);r a.recycle;r setOrientation(orientation);r }r r public void setOrientation( int orientation) {r if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST) {r throw new IllegalArgumentException( "invalid orientation");r }r mOrientation = orientation;r }r r @Overrider public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {r if (mOrientation == VERTICAL_LIST) {r drawVertical(c, parent);r } else {r drawHorizontal(c, parent);r }r }r r r public void drawVertical(Canvas c, RecyclerView parent) {r final int left = parent.getPaddingLeft;r final int right = parent.getWidth - parent.getPaddingRight;r r final int childCount = parent.getChildCount;r for (int i = 0; i < childCount; i++) {r final View child = parent.getChildAt(i);r final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) childr .getLayoutParams;r final int top = child.getBottom + params.bottomMargin;r final int bottom = top + mDivider.getIntrinsicHeight;r mDivider.setBounds(left, top, right, bottom);r mDivider.draw(c);r }r }r r public void drawHorizontal(Canvas c, RecyclerView parent) {r final int top = parent.getPaddingTop;r final int bottom = parent.getHeight - parent.getPaddingBottom;r r final int childCount = parent.getChildCount;r for (int i = 0; i < childCount; i++) {r final View child = parent.getChildAt(i);r final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) childr .getLayoutParams;r final int left = child.getRight + params.rightMargin;r final int right = left + mDivider.getIntrinsicHeight;r mDivider.setBounds(left, top, right, bottom);r mDivider.draw(c);r }r }r r @Overrider public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {r super.getItemOffsets(outRect, view, parent, state);r if (mOrientation == VERTICAL_LIST) {r outRect.set(0, 0, 0, mDivider.getIntrinsicHeight);r }else{r outRect.set(0, 0, mDivider.getIntrinsicWidth, 0);r }r }r }r

这样使用的是系统的分割线。

这样在Style中可以自己更改。

<resources>r r <!-- Base application theme. -->r <style name="AppTheme" parent="Theme.AppCompat.Light.DarkActionBar">r <!-- Customize your theme here. -->r <item name="colorPrimary">@color/colorPrimary</item>r <item name="colorPrimaryDark">@color/colorPrimaryDark</item>r <item name="colorAccent">@color/colorAccent</item>r r <item name="android:listDivider">@drawable/divider_bg</item>r </style>r r r </resources>r

自定义一个Drawble

<?xml version="1.0" encoding="utf-8"?>r <shape xmlns:android="http://schemas.android.com/apk/res/android"r android:shape="rectangle" >r r <gradientr android:centerColor="#ff00ff00"r android:endColor="#ff0000ff"r android:startColor="#ffff0000"r android:type="linear" />r <size android:height="4dp"/>r r </shape>r

别忘了去把之前我给的MainActivity.java中把分割线那句代码解去注释。

//增加分割线r recyclerView.addItemDecoration(new MyDividerItemDecoration(this,MyDividerItemDecoration.VERTICAL_LIST));r

最后上一波简单的运行图吧。

好了，我也说的不是很多，大家可以通过更多搜索出你想要的！