版权声明：本文为HaiyuKing原创文章，转载请注明出处！
前言
VirtualLayout是一个针对RecyclerView的LayoutManager扩展, 主要提供一整套布局方案和布局间的组件复用的问题。
设计思路
通过定制化的LayoutManager，接管整个RecyclerView的布局逻辑；LayoutManager管理了一系列LayoutHelper，LayoutHelper负责具体布局逻辑实现的地方；每一个LayoutHelper负责页面某一个范围内的组件布局；不同的LayoutHelper可以做不同的布局逻辑，因此可以在一个RecyclerView页面里提供异构的布局结构，这就能比系统自带的LinearLayoutManager、GridLayoutManager等提供更加丰富的能力。同时支持扩展LayoutHelper来提供更多的布局能力。
主要功能
- 默认通用布局实现，解耦所有的View和布局之间的关系: Linear, Grid, 吸顶, 浮动, 固定位置等。
- LinearLayoutHelper: 线性布局
- GridLayoutHelper: Grid布局， 支持横向的colspan
- FixLayoutHelper: 固定布局，始终在屏幕固定位置显示
- ScrollFixLayoutHelper: 固定布局，但之后当页面滑动到该图片区域才显示, 可以用来做返回顶部或其他书签等
- FloatLayoutHelper: 浮动布局，可以固定显示在屏幕上，但用户可以拖拽其位置
- ColumnLayoutHelper: 栏格布局，都布局在一排，可以配置不同列之间的宽度比值
- SingleLayoutHelper: 通栏布局，只会显示一个组件View
- OnePlusNLayoutHelper: 一拖N布局，可以配置1-5个子元素
- StickyLayoutHelper: stikcy布局， 可以配置吸顶或者吸底
- StaggeredGridLayoutHelper: 瀑布流布局，可配置间隔高度/宽度
- 上述默认实现里可以大致分为两类：一是非fix类型布局，像线性、Grid、栏格等，它们的特点是布局在整个页面流里，随页面滚动而滚动；另一类就是fix类型的布局，它们的子节点往往不随页面滚动而滚动。
- 所有除布局外的组件复用，VirtualLayout将用来管理大的模块布局组合，扩展了RecyclerView，使得同一RecyclerView内的组件可以复用，减少View的创建和销毁过程。
使用
这个demo只是简单记录下上面黄色标记的几种布局的实现。
注意
vlayout1.2.8版本中使用的recyclerview是23.1.1版本，v4是23.1.1，这个需要注意。如果项目中用到recyclerview和v4包的话，建议依赖新版本的recyclerview和v4。
下面是vlayout的build.gradle文件的部分源码：
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
// compile project(':extension')
if (project.hasProperty('useNewSupportLibrary')) {
compile 'com.android.support:recyclerview-v7:25.2.0@aar'
compile('com.android.support:support-v4:25.2.0@aar')
compile 'com.android.support:support-annotations:25.2.0'
compile 'com.android.support:support-compat:25.2.0'
compile 'com.android.support:support-core-ui:25.2.0'
} else {
compile 'com.android.support:recyclerview-v7:23.1.1@aar'
compile('com.android.support:support-v4:23.1.1@aar') {
exclude group: 'com.android.support', module: 'support-annotations'
}
compile 'com.android.support:support-annotations:23.1.1'
}
androidTestCompile "org.robolectric:robolectric:3.0"
}
所以在项目中app目录的build.gradle中依赖vlayout时，会有这样的提醒：
效果图
使用步骤
一、项目组织结构图
注意事项：
1、 导入类文件后需要change包名以及重新import R文件路径
2、 Values目录下的文件（strings.xml、dimens.xml、colors.xml等），如果项目中存在，则复制里面的内容，不要整个覆盖
二、导入步骤
1、在build.gradle文件中依赖vlayout
apply plugin: 'com.android.application'
android {
compileSdkVersion 28
defaultConfig {
applicationId "com.why.project.vlayoutdemo"
minSdkVersion 16
targetSdkVersion 28
versionCode 1
versionName "1.0"
testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support.constraint:constraint-layout:1.1.3'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.2'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
//Vlayout
implementation ('com.alibaba.android:vlayout:1.2.8@aar') {
transitive = true
}
//下面的代码，根据实际情况添加，如果项目中用到了下面的库，则需要根据项目依赖高版本库，否则就会使用vlayout中的低版本库
//RecyclerView【因为vlayout中的recyclerview版本低，所以需要重新依赖高版本，否则app中使用recyclerview的话会直接使用vlayout中的低版本recyclerview】
implementation "com.android.support:recyclerview-v7:28.0.0"
//v4
implementation 'com.android.support:support-v4:28.0.0'
}
这样就将vlayout集成到项目中了。
三、使用方法
1、先在demo中添加测试数据文件
{ "data": [ { "modelname": "推送新闻", "data": [ { "image": "https://imgsa.baidu.com/news/q%3D100/sign=06d12a2732dbb6fd235be1263925aba6/b151f8198618367a8dbfe10125738bd4b31ce53c.jpg", "url": "http://news.ifeng.com/a/20180120/55302258_0.shtml?_zbs_baidu_news", "title": "安徽合肥：“非遗”进校园", "id": "whyidzhi", "order": "1" } ] }, { "modelname": "焦点新闻", "data": [ { "image": "https://b.bdstatic.com/boxlib/20180120/2018012017100383423448679.jpg", "url": "http://pic.chinadaily.com.cn/2018-01/20/content_35544757.htm", "title": "西昌铁路警方用表情包宣传爱路小知识", "id": "whyidzhi", "order": "1" }, { "image": "https://b.bdstatic.com/boxlib/20180120/2018012017100311270281486.jpg", "url": "http://pic.chinadaily.com.cn/2018-01/20/content_35544758.htm", "title": "成都熊猫基地太阳产房全新升级", "id": "whyidzhi", "order": "2" }, { "image": "https://b.bdstatic.com/boxlib/20180120/2018012017100392134086973.jpg", "url": "http://pic.chinadaily.com.cn/2018-01/20/content_35544759.htm", "title": "长沙“90后”交警用手绘记录交警故事", "id": "whyidzhi", "order": "3" } ] }, { "modelname": "国际人物", "data": [ { "image": "http://t12.baidu.com/it/u=264843290,870648681&fm=173&s=29C043870E531CDC082897A003006015&w=218&h=146&img.JPEG", "url": "http://news.163.com/18/0120/15/D8JS570V00018AOQ_all_mobile.html", "title": "法总统马克龙会见默克尔 强调欧洲改革需要德国（全文..", "id": "whyidzhi", "order": "1" }, { "image": "", "url": "http://www.yidianzixun.com/article/0IBPUBcu", "title": "默克尔组阁能否成功？全等这场党代会", "id": "whyidzhi", "order": "2" }, { "image": "", "url": "http://www.yidianzixun.com/article/0IBMT9yr", "title": "马克龙向默克尔表支持 强调推动欧洲改革需要德国", "id": "whyidzhi", "order": "3" }, { "image": "", "url": "http://news.sina.com.cn/w/2018-01-20/doc-ifyquixe4989529.shtml", "title": "德法首脑在巴黎会晤 默克尔：欧洲需要稳定的德国政府", "id": "whyidzhi", "order": "4" }, { "image": "", "url": "http://news.sina.com.cn/o/2018-01-20/doc-ifyqtycx0664636.shtml", "title": "德国社民党民众支持率创新低", "id": "whyidzhi", "order": "5" } ] }, { "modelname": "图片新闻", "data": [ { "image": "https://t10.baidu.com/it/u=44207055,3448633405&fm=173&s=CFF20CC150452CEC9F9C491103005092&w=218&h=146&img.JPEG", "url": "http://war.163.com/18/0120/11/D8JEFM5D000181KT_mobile.html", "title": "外媒称朝鲜先遣队取消访韩", "id": "whyidzhi", "order": "1" }, { "image": "https://t10.baidu.com/it/u=1625316837,2876937793&fm=173&s=F507703317115D6644753AE80300E036&w=218&h=146&img.JPEG", "url": "http://news.china.com/internationalgd/10000166/20180120/31985304.html", "title": "狂风横扫欧洲多国，致10人", "id": "whyidzhi", "order": "2" }, { "image": "https://t10.baidu.com/it/u=2946973968,4057971581&fm=173&s=2D216D93C2F00B9219A825E703009060&w=218&h=146&img.JPEG", "url": "http://news.sina.com.cn/w/2018-01-20/doc-ifyqtycx0654102.shtml", "title": "津巴布韦反对党要人在美坠", "id": "whyidzhi", "order": "3" }, { "image": "https://t12.baidu.com/it/u=3788697896,2880168169&fm=173&s=D31A38C4D664D55FC29281010300309B&w=218&h=146&img.JPEG", "url": "http://finance.ifeng.com/a/20180120/15937975_0.shtml", "title": "美国政府关门 比特币闻讯", "id": "whyidzhi", "order": "4" }, { "image": "https://t10.baidu.com/it/u=1499851317,895362806&fm=173&s=BD04DF104871339C53A88C870100E0E3&w=218&h=146&img.JPEG", "url": "http://news.sina.com.cn/o/2018-01-20/doc-ifyquixe5136803.shtml", "title": "刚刚，美国政府正式宣告", "id": "whyidzhi", "order": "5" }, { "image": "https://t12.baidu.com/it/u=4229963978,641890755&fm=173&s=74B218D646A08B491AAF3E9903001088&w=218&h=146&img.JPEG", "url": "http://www.chinanews.com/gj/2018/01-20/8428898.shtml", "title": "超三成受访者称中国是“新", "id": "whyidzhi", "order": "6" } ] }, { "modelname": "视频新闻", "data": [ { "image": "http://pic.rmb.bdstatic.com/1f01839d477aa7a3ffa36f07542f8d5b.jpg@h_660,w_370", "url": "http://v.qq.com/x/page/h0527p90e2b.html", "title": "杭州餐馆爆炸，路过公交车20余人受伤", "id": "whyidzhi", "order": "1" }, { "image": "http://pic.rmb.bdstatic.com/1f541422405ab18797795c0adc3318eb.jpg@h_660,w_370", "url": "http://www.iqiyi.com/v_19rr7omigs.html", "title": "中央措辞严厉批祁连山生态问题 8责任人被问责", "id": "whyidzhi", "order": "2" }, { "image": "http://pic.rmb.bdstatic.com/d46f662c1900de051da6de2eef2c485f.jpg@h_660,w_370", "url": "http://v.qq.com/x/page/a0024q7bkg0.html", "title": "吉林永吉 吉林市多地遭暴雨袭击 县城灾后清理正在进行", "id": "whyidzhi", "order": "3" }, { "image": "http://pic.rmb.bdstatic.com/b9cdfca4adeb36ac1a0730f70b9d63f9.jpg@h_660,w_370", "url": "http://www.iqiyi.com/v_19rr7oosfs.html", "title": "40 高温下一出租车行驶中自燃", "id": "whyidzhi", "order": "4" }, { "image": "http://pic.rmb.bdstatic.com/660e5152b144e48bbdffdad5d9fdc088.jpg@h_660,w_370", "url": "http://v.qq.com/x/page/v0527bhjwh3.html", "title": "徐光裕：印度航母只是二流航母", "id": "whyidzhi", "order": "5" } ] } ] }
2、因为Demo中使用到了banner和图片展现，所以还需要依赖banner和glide
参考《BannerDemo【图片轮播图控件】》、《GlideNewDemo【Glide4.7.1版本的简单使用以及圆角功能】》
3、在布局文件声明Recyclerview控件
<?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" android:orientation="vertical"> <android.support.v7.widget.RecyclerView android:id="@+id/vlayout_rv" android:layout_width="match_parent" android:layout_height="match_parent" android:scrollbars="none" android:clipToPadding="true" android:paddingLeft="0dp" android:paddingRight="0dp" android:requiresFadingEdge="none"/> </LinearLayout>
4、在Acitivity中参考下面的代码编写基本框架（也就是逻辑处理）
package com.why.project.vlayoutdemo; import android.content.Context; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.support.v7.widget.RecyclerView; import android.util.Log; import android.widget.Toast; import com.alibaba.android.vlayout.DelegateAdapter; import com.alibaba.android.vlayout.VirtualLayoutManager; import com.alibaba.android.vlayout.layout.GridLayoutHelper; import com.alibaba.android.vlayout.layout.LinearLayoutHelper; import com.alibaba.android.vlayout.layout.SingleLayoutHelper; import com.alibaba.android.vlayout.layout.StickyLayoutHelper; import com.why.project.vlayoutdemo.adapter.BannerLayoutAdapter; import com.why.project.vlayoutdemo.adapter.GridLayoutAdapter; import com.why.project.vlayoutdemo.adapter.HorizontalListLayoutAdapter; import com.why.project.vlayoutdemo.adapter.ListLayoutAdapter; import com.why.project.vlayoutdemo.adapter.StickyTitleAdapter; import com.why.project.vlayoutdemo.bean.ItemBean; import com.why.project.vlayoutdemo.bean.ModelBean; import org.json.JSONArray; import org.json.JSONException; import org.json.JSONObject; import java.io.ByteArrayOutputStream; import java.io.InputStream; import java.util.ArrayList; import java.util.LinkedList; import java.util.List; public class MainActivity extends AppCompatActivity { private static final String TAG = MainActivity.class.getSimpleName(); private List<ModelBean> mModelBeanList;//列表数据集合 private RecyclerView mVLayoutRV; private VirtualLayoutManager layoutManager; private DelegateAdapter delegateAdapter; private List<DelegateAdapter.Adapter> adapters; private RecyclerView.RecycledViewPool viewPool;//设置复用池的大小 private int itemType;//一个Adapter对应一个类型，这里通过自增加1实现唯一性 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initViews(); initDatas(); } private void initViews() { mVLayoutRV = findViewById(R.id.vlayout_rv); } private void initDatas() { //初始化列表数据集合 mModelBeanList = new ArrayList<ModelBean>(); getTestDatas(); Log.e(TAG,"mModelBeanList.size()=" + mModelBeanList.size()); //初始化LayoutManager layoutManager = new VirtualLayoutManager(this); layoutManager.setRecycleOffset(300); mVLayoutRV.setLayoutManager(layoutManager); //设置回收复用池大小，（如果一屏内相同类型的 View 个数比较多，需要设置一个合适的大小，防止来回滚动时重新创建 View） //针对type=0的item设置了复用池的大小，如果你的页面有多种type，需要为每一种类型的分别调整复用池大小参数。 viewPool = new RecyclerView.RecycledViewPool(); mVLayoutRV.setRecycledViewPool(viewPool); //加载数据，通过创建adapter集合实现布局 delegateAdapter = new DelegateAdapter(layoutManager, false);//必须使用false，实现每一个分组的类型不同 mVLayoutRV.setAdapter(delegateAdapter); setVLayoutAdapter(); } /**设置适配器*/ private void setVLayoutAdapter() { itemType = 0;//自增加1 if (adapters != null) { adapters.clear(); } else { adapters = new LinkedList<>(); } //根据类型不同，采用不同的adapter并添加到集合中 for(int i=0; i<mModelBeanList.size(); i++){ String modelName = mModelBeanList.get(i).getModelName(); String type = mModelBeanList.get(i).getType(); ArrayList<ItemBean> itemBeanArrayList = (ArrayList<ItemBean>) mModelBeanList.get(i).getItemDataList(); boolean showModelName = true;//控制是否显示model，也就是吸顶布局 if(showModelName){ //stikcy布局， 可以配置吸顶或者吸底 //设置各个区域的复用池的大小，因为只有一个元素，所以复用池大小就设置为1 viewPool.setMaxRecycledViews(itemType++, 1); StickyLayoutHelper stickyLayoutHelper = new StickyLayoutHelper(); StickyTitleAdapter stickyTitleAdapter = new StickyTitleAdapter(this,stickyLayoutHelper,modelName); adapters.add(stickyTitleAdapter); } //========用来判断分组，展现不同的样式======== //每一个item对应一种样式 switch(type) { case "banner": //通栏布局——轮播图 //设置各个区域的复用池的大小，设置子集合的总个数为复用池大小 viewPool.setMaxRecycledViews(itemType++, itemBeanArrayList.size()); SingleLayoutHelper singleLayoutHelper = new SingleLayoutHelper();//通栏布局，只会显示一个组件View singleLayoutHelper.setMargin(0, 0, 0, dip2px(this, 10));//设置外边距，实现分割效果 BannerLayoutAdapter bannerLayoutAdapter = new BannerLayoutAdapter(this, singleLayoutHelper, itemBeanArrayList); bannerLayoutAdapter.setBannerCallback(new BannerLayoutAdapter.BannerCallback() { @Override public void clickBanner(ItemBean itemBean) { Toast.makeText(MainActivity.this,itemBean.getTitle(),Toast.LENGTH_SHORT).show(); } });//设置自定义回调，用于点击事件监听 adapters.add(bannerLayoutAdapter); break; case "hori": //通栏布局——横向列表 //设置各个区域的复用池的大小，设置子集合的总个数为复用池大小 viewPool.setMaxRecycledViews(itemType++, itemBeanArrayList.size()); SingleLayoutHelper horizontalListLayoutHelper = new SingleLayoutHelper();//不使用LinearLayoutHelper horizontalListLayoutHelper.setMargin(0,0,0,dip2px(this, 10));//设置外边距，实现分割效果 HorizontalListLayoutAdapter horizontalListLayoutAdapter = new HorizontalListLayoutAdapter(this,horizontalListLayoutHelper,itemBeanArrayList); horizontalListLayoutAdapter.setHorizontalListCallback(new HorizontalListLayoutAdapter.HorizontalListCallback() { @Override public void clickHorizontalItem(ItemBean itemBean) { Toast.makeText(MainActivity.this,itemBean.getTitle(),Toast.LENGTH_SHORT).show(); } });//设置自定义回调，用于点击事件监听 adapters.add(horizontalListLayoutAdapter); break; case "grid": //九宫格布局 //设置各个区域的复用池的大小，设置子集合的总个数为复用池大小 viewPool.setMaxRecycledViews(itemType++, itemBeanArrayList.size()); GridLayoutHelper gridlayoutHelper = new GridLayoutHelper(2);//Grid布局， 支持横向的colspan gridlayoutHelper.setAutoExpand(false);//解决单数的时候，最后一张居中显示的问题 gridlayoutHelper.setMargin(0, 0, 0, dip2px(this, 10));//设置外边距，实现分割效果 GridLayoutAdapter gridLayoutAdapter = new GridLayoutAdapter(this, gridlayoutHelper, itemBeanArrayList, itemBeanArrayList.size()); //设置自定义回调，用于点击事件监听 gridLayoutAdapter.setGridCallback(new GridLayoutAdapter.GridCallback() { @Override public void clickGrid(ItemBean itemBean) { Toast.makeText(MainActivity.this,itemBean.getTitle(),Toast.LENGTH_SHORT).show(); } }); adapters.add(gridLayoutAdapter); break; case "list": //列表布局（默认布局） //设置各个区域的复用池的大小，设置子集合的总个数为复用池大小 viewPool.setMaxRecycledViews(itemType++, itemBeanArrayList.size()); LinearLayoutHelper linearLayoutHelper = new LinearLayoutHelper();//线性布局 linearLayoutHelper.setMargin(0, 0, 0, dip2px(this, 10));//设置外边距，实现分割效果 ListLayoutAdapter listLayoutAdapter = new ListLayoutAdapter(this, linearLayoutHelper, itemBeanArrayList, itemBeanArrayList.size()); //设置自定义回调，用于点击事件监听 listLayoutAdapter.setListCallback(new ListLayoutAdapter.ListCallback() { @Override public void clickList(ItemBean itemBean) { Toast.makeText(MainActivity.this,itemBean.getTitle(),Toast.LENGTH_SHORT).show(); } }); adapters.add(listLayoutAdapter); break; default: } } delegateAdapter.setAdapters(adapters); } /** * dp转px * 16dp - 48px * 17dp - 51px*/ public static int dip2px(Context context, float dpValue) { float scale = context.getResources().getDisplayMetrics().density; return (int)((dpValue * scale) + 0.5f); } /*=======================================获取测试数据==============================================*/ private void getTestDatas(){ String listdata = getStringFromAssert(MainActivity.this,"vlayout.txt"); try { JSONObject listObj = new JSONObject(listdata); JSONArray listArray = listObj.getJSONArray("data"); for(int i=0; i< listArray.length(); i++){ JSONObject itemObj = listArray.getJSONObject(i); ModelBean modelBean = new ModelBean(); modelBean.setModelName(itemObj.getString("modelname")); modelBean.setType(itemObj.getString("type")); JSONArray childArray = itemObj.getJSONArray("data"); List<ItemBean> itemBeanList = new ArrayList<ItemBean>(); for(int j=0; j<childArray.length(); j++){ JSONObject childObj = childArray.getJSONObject(j); ItemBean itemBean = new ItemBean(); itemBean.setId(childObj.getString("id")); itemBean.setImageUrl(childObj.getString("image")); itemBean.setOrder(childObj.getString("order")); itemBean.setTitle(childObj.getString("title")); itemBean.setUrlPath(childObj.getString("url")); itemBeanList.add(itemBean); } modelBean.setItemDataList(itemBeanList); mModelBeanList.add(modelBean); } } catch (JSONException e) { e.printStackTrace(); } } /** * 访问assets目录下的资源文件，获取文件中的字符串 * @param assetsFilePath - 文件的相对路径，例如："listitemdata.txt或者"/why/listdata.txt" * @return 内容字符串 * */ public static String getStringFromAssert(Context mContext, String assetsFilePath) { String content = ""; // 结果字符串 try { InputStream is = mContext.getResources().getAssets().open(assetsFilePath);// 打开文件 int ch = 0; ByteArrayOutputStream out = new ByteArrayOutputStream(); // 实现了一个输出流 while ((ch = is.read()) != -1) { out.write(ch); // 将指定的字节写入此 byte 数组输出流 } byte[] buff = out.toByteArray();// 以 byte 数组的形式返回此输出流的当前内容 out.close(); // 关闭流 is.close(); // 关闭流 content = new String(buff, "UTF-8"); // 设置字符串编码 } catch (Exception e) { Toast.makeText(mContext, "对不起，没有找到指定文件！", Toast.LENGTH_SHORT) .show(); } return content; } }
5、添加各种adapter和布局文件
混淆配置
#Vlayout
-keepattributes InnerClasses
-keep class com.alibaba.android.vlayout.ExposeLinearLayoutManagerEx { *; }
-keep class android.support.v7.widget.RecyclerView$LayoutParams { *; }
-keep class android.support.v7.widget.RecyclerView$ViewHolder { *; }
-keep class android.support.v7.widget.ChildHelper { *; }
-keep class android.support.v7.widget.ChildHelper$Bucket { *; }
-keep class android.support.v7.widget.RecyclerView$LayoutManager { *; }