通过Data Binding为RecyclerView打造通用Adapter

我们使用Data Binding库一步步为RecyclerView打造通用的Adapter，今天我们先来编写单一Item时的Adapter：SimpleAdapter。至于如何在项目中添加Data Binding库，在次不再涉及，敬请自行Google或Android DataBinding介绍。

第一步：通用的ViewHolder

package com.dfsebook.myrecycleradapter.view;import android.databinding.ViewDataBinding;import android.support.v7.widget.RecyclerView;import android.view.View;/** * Created by Administrator on 16-7-18. */public class ViewHolder extends RecyclerView.ViewHolder{   private ViewDataBinding binding;    public ViewDataBinding getBinding() {        return binding;    }    public void setBinding(ViewDataBinding binding) {        this.binding = binding;    }    public ViewHolder(View itemView) {        super(itemView);    }}

第二步：通用Adapter

package com.dfsebook.myrecycleradapter.adapter;import android.databinding.DataBindingUtil;import android.databinding.ViewDataBinding;import android.support.v7.widget.RecyclerView;import android.view.LayoutInflater;import android.view.ViewGroup;import com.dfsebook.myrecycleradapter.view.ViewHolder;import java.util.List;/** * Created by Administrator on 16-7-18. */public class SimpleAdapter<T> extends RecyclerView.Adapter<ViewHolder>{    private List<T> mDatas;    private int layoutId;    private int brId;    public SimpleAdapter(List<T> mDatas, int layoutId, int brId) {        this.mDatas = mDatas;        this.layoutId = layoutId;        this.brId = brId;    }    @Override    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {        LayoutInflater inflater = LayoutInflater.from(parent.getContext());        ViewDataBinding binding = DataBindingUtil.inflate(inflater, layoutId, parent, false);        ViewHolder viewHolder = new ViewHolder(binding.getRoot());        viewHolder.setBinding(binding);        return viewHolder;    }    @Override    public void onBindViewHolder(ViewHolder holder, int position) {        holder.getBinding().setVariable(brId,mDatas.get(position));        holder.getBinding().executePendingBindings();    }    @Override    public int getItemCount() {        return mDatas == null ? 0 : mDatas.size();    }}

至此准备工作基本结束，下面我们通过一个例子运用一下SimpleAdapter。

一、准备Bean：Student

package com.dfsebook.myrecycleradapter.bean;/** * Created by Administrator on 16-7-18. */public class Student {    private int resId;    private String name;    public Student(int resId, String name) {        this.resId = resId;        this.name = name;    }    public int getResId() {        return resId;    }    public void setResId(int resId) {        this.resId = resId;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }}

二、Item布局文件 student_item.xml

<?xml version="1.0" encoding="utf-8"?><layout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto">    <data>        <import type="com.dfsebook.myrecycleradapter.bean.Student"/>        <variable name="student" type="Student"/>    </data>    <LinearLayout        android:layout_width="fill_parent"        android:layout_height="fill_parent"        android:gravity="center">        <ImageView            android:layout_width="80dp"            android:layout_height="80dp"            android:layout_margin="10dp"            app:studentAvatar="@{student.resId}"/>        <TextView            android:layout_width="fill_parent"            android:layout_height="wrap_content"            android:layout_marginLeft="40dp"            android:gravity="center"            android:text="@{student.name}"            android:textSize="18sp" />    </LinearLayout></layout>

三、自定义绑定行为 BindingUtil

package com.dfsebook.myrecycleradapter.utils;import android.databinding.BindingAdapter;import android.widget.ImageView;/** * Created by Administrator on 16-7-18. */public class BindingUtil {    @BindingAdapter("bind:studentAvatar")    public static void showImageByUrl(final ImageView imageView,int resId){        imageView.setImageResource(resId);    }}

四、主布局

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="match_parent"    android:layout_height="match_parent">    <android.support.v7.widget.RecyclerView        android:id="@+id/show_list"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:scrollbars="vertical" /></LinearLayout>

五、代码实现：MainActivity.java

package com.dfsebook.myrecycleradapter.activity;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.RecyclerView;import com.dfsebook.myrecycleradapter.BR;import com.dfsebook.myrecycleradapter.utils.InitRecyclerView;import com.dfsebook.myrecycleradapter.R;import com.dfsebook.myrecycleradapter.adapter.CommonAdapter;import com.dfsebook.myrecycleradapter.bean.Student;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        RecyclerView recyclerView = (RecyclerView)findViewById(R.id.show_list);        List<Student> students = new ArrayList<>();        Student student = new Student(R.drawable.tx2,"Kate");        students.add(student);        student = new Student(R.drawable.tx3,"Kate");        students.add(student);        student = new Student(R.drawable.tx4,"Johnson");        students.add(student);        student = new Student(R.drawable.tx5,"Make");        students.add(student);        CommonAdapter<Student> adapter = new CommonAdapter<Student>(students,R.layout.student_item, BR.student);        recyclerView.setAdapter(adapter);    }}

六、辅助工具类InitRecyclerView

package com.dfsebook.myrecycleradapter.utils;import android.content.Context;import android.support.v7.widget.DefaultItemAnimator;import android.support.v7.widget.LinearLayoutManager;import android.support.v7.widget.RecyclerView;import android.support.v7.widget.StaggeredGridLayoutManager;/** * Created by Administrator on 15-9-17. */public class InitRecyclerView {    public static void initLinearLayoutVERTICAL(Context context,RecyclerView recyclerView){        LinearLayoutManager layoutManager = new LinearLayoutManager(context);        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);        recyclerView.setLayoutManager(layoutManager);        recyclerView.setItemAnimator(new DefaultItemAnimator());    }    public static void initLinearLayoutWithoutDivid(Context context,RecyclerView recyclerView){        LinearLayoutManager layoutManager = new LinearLayoutManager(context);        layoutManager.setOrientation(LinearLayoutManager.VERTICAL);        recyclerView.setLayoutManager(layoutManager);        recyclerView.setItemAnimator(new DefaultItemAnimator());    }    public static void initLinearLayoutHorizontal(Context context,RecyclerView recyclerView){        LinearLayoutManager layoutManager = new LinearLayoutManager(context);        layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);        recyclerView.setLayoutManager(layoutManager);        recyclerView.setItemAnimator(new DefaultItemAnimator());    }    public static void initStaggered(Context context,RecyclerView recyclerView){        StaggeredGridLayoutManager sgm = new StaggeredGridLayoutManager(3,StaggeredGridLayoutManager.VERTICAL);        recyclerView.setLayoutManager(sgm);        recyclerView.setItemAnimator(new DefaultItemAnimator());    }}

收工，运行截图如下