Android RecycleView 自定义Item的使用

自定义布局的RecycleView需要自己实现Adapter，ViewHolder和布局；

自定义Adapter继承RecycleView.Adapter，重写getItemCount()，onBindViewHolder()和onCreateViewHolder()；

自定义ViewHolder继承于RecycleView.ViewHolder；

getItemCount()返回RecycleView中Item的个数，onBindViewHolder()主要实现数据和布局的绑定，onCreateViewHolder()加载布局；

效果：

适配器代码：

package com.cloud.recycleviewdemo;

import android.support.annotation.NonNull;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.List;

class RecycleViewAdapter extends RecyclerView.Adapter<RecycleViewAdapter.ItemHolder> {

    private List<Item> mItems;

    RecycleViewAdapter(List<Item> items) {
        mItems = items;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ItemHolder holder, int position) {
        //设置Item图片
        holder.image.setImageResource(mItems.get(position).getImageResId());
        //设置Item文字
        holder.title.setText(mItems.get(position).getTitle());
    }

    @NonNull
    @Override
    public ItemHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new ItemHolder(LayoutInflater
                .from(parent.getContext()).inflate(R.layout.item, parent, false));
    }

    class ItemHolder extends RecyclerView.ViewHolder {

        ImageView image;
        TextView title;

        ItemHolder(View item) {
            super(item);
            image = item.findViewById(R.id.image_view);
            title = item.findViewById(R.id.text_title);
        }
    }
}

Item类：

package com.cloud.recycleviewdemo;

class Item {

    private int mImageResId;
    private String mTitle;

    Item(int imageResId, String title) {
        mImageResId = imageResId;
        mTitle = title;
    }

    public int getImageResId() {
        return mImageResId;
    }

    public void setImageResId(int imageResId) {
        mImageResId = imageResId;
    }

    public String getTitle() {
        return mTitle;
    }

    public void setTitle(String title) {
        mTitle = title;
    }
}

MainActivity代码：

package com.cloud.recycleviewdemo;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.DefaultItemAnimator;
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 mRecyclerView;
    private LinearLayoutManager mLinearLayoutManager;
    private RecycleViewAdapter mRecycleViewAdapter;

    private List<Item> mData;

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

        bindViews();
        initData();
        //初始化线性布局管理器
        mLinearLayoutManager = new LinearLayoutManager(this);
        //设置布局管理器
        mRecyclerView.setLayoutManager(mLinearLayoutManager);
        mRecyclerView.setItemAnimator(new DefaultItemAnimator());
        //初始化适配器
        mRecycleViewAdapter = new RecycleViewAdapter(mData);
        //设置适配器
        mRecyclerView.setAdapter(mRecycleViewAdapter);
    }

    private void bindViews() {
        mRecyclerView = findViewById(R.id.recycle_view);
    }

    private void initData() {
        mData = new ArrayList<>();
        mData.add(new Item(R.drawable.witcher, "The Witcher 3: Wild Hunt"));
        mData.add(new Item(R.drawable.recore, "Recore"));
        mData.add(new Item(R.drawable.origins, "Assassin's Creed Origins"));
        mData.add(new Item(R.drawable.hunter, "theHunter: Call of the Wild"));
    }
}

Item布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
    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:orientation="vertical"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_margin="4dp"
    android:elevation="2dp"
    android:background="@drawable/background_item">

    <ImageView
        android:id="@+id/image_view"
        android:contentDescription="@null"
        android:layout_width="0dp"
        android:layout_height="235dp"
        android:layout_margin="6dp"
        tools:src="@drawable/witcher"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent" />

    <TextView
        android:id="@+id/text_title"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="18sp"
        android:textColor="#000000"
        android:layout_margin="6dp"
        android:paddingBottom="4dp"
        app:layout_constraintTop_toBottomOf="@+id/image_view"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintBottom_toBottomOf="parent"
        tools:text="The Witcher 3: Wild Hunt" />

</android.support.constraint.ConstraintLayout>

MainActivity布局：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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"
    tools:context=".MainActivity">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="48dp"
        android:background="@color/colorPrimary"
        android:elevation="5dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent">

        <ImageView
            android:contentDescription="@null"
            android:layout_width="36dp"
            android:layout_height="36dp"
            android:src="@drawable/icon" />

        <TextView
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:text="@string/app_name"
            android:textColor="#FFFFFF"
            android:textSize="18sp" />

    </android.support.v7.widget.Toolbar>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycle_view"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/toolbar"
        app:layout_constraintVertical_bias="1.0">

    </android.support.v7.widget.RecyclerView>

</android.support.constraint.ConstraintLayout>