RecycleView

[TOC]

---

需要以下依赖：

implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.android.support:recyclerview-v7:28.0.0'
//implementation 'com.android.support:design:28.0.0' 用这一句换上面那句也可以

根据自己android.support 版本去调整recycleView依赖版本

布局

​ 实现布局：

<android.support.v7.widget.RecyclerView
    android:id="@+id/rv"
    android:background="@color/colorPrimary"
    android:layout_margin="10dp"
    android:layout_width="match_parent"
    android:layout_height="match_parent">
</android.support.v7.widget.RecyclerView>

​ 实现子布局：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/cell_bg"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content">
    <RelativeLayout
        android:layout_width="wrap_content"
        android:layout_height="50dp"
        android:layout_margin="10dp"
        android:gravity="center">
        <ImageView
            android:id="@+id/iv_icon"
            android:src="@drawable/icon_computer"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
        <TextView
            android:id="@+id/tv_text"
            android:layout_marginTop="5dp"
            android:gravity="center"
            android:layout_alignParentStart="true"
            android:layout_alignParentLeft="true"
            android:text="computer"
            android:layout_below="@+id/iv_icon"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </RelativeLayout>
</RelativeLayout>

​

自定义类

​ 自定义类记载每个子布局上面的控件的数据信息：

public class MyCellClass {
    String text;
    int image;

    public MyCellClass(String text, int image) {
        this.text = text;
        this.image = image;
    }
}

适配器和ViewHolder

MyViewHolder用来记载每个itemView的控件信息：

class MyViewHolder extends RecyclerView.ViewHolder {
    TextView tv;
    ImageView iv;
    RelativeLayout bg;
    public MyViewHolder(View itemView) {
        super(itemView);
        bg = (RelativeLayout) itemView.findViewById(R.id.cell_bg);
        iv = (ImageView)itemView.findViewById(R.id.iv_icon);
        tv = (TextView)itemView.findViewById(R.id.tv_text);
    }
}

ps ：我将适配器和MyViewHolder写在一个文件中

​ 写一个适配器继承 RecyclerView.Adapter<MyViewHolder>

​ 需要继承三个方法分别是

• onCreateViewHolder
• onBindViewHolder
• getItemCount

使用一个链表记录所有子布局上面的所有数据信息：

private LinkedList<MyCellClass> cellList = new LinkedList<>();

可以在构造函数将其赋值：

public MyRecycleAdapter(Context context) {
    cellList.add(new MyCellClass("1",R.drawable.icon_computer));
    cellList.add(new MyCellClass("1",R.drawable.icon_computer));
    cellList.add(new MyCellClass("1",R.drawable.icon_computer));
    cellList.add(new MyCellClass("1",R.drawable.icon_computer));
    cellList.add(new MyCellClass("1",R.drawable.icon_computer));
    this.context = context;
    mInflater = LayoutInflater.from(context);
}

<a name="onCreateViewHolder">onCreateViewHolder函数</a>，负责承载每个子项的布局,目的是创建viewHolder

@Override
public MyViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    View view = mInflater.inflate(R.layout.ceil_layout,viewGroup,false); //注意要写第三个参数为false
    MyViewHolder myViewHolder = new MyViewHolder(view);
    return myViewHolder;
}

<a name="onBindViewHolder">onBindViewHolder函数</a>，负责将每个子项holder绑定数据。调用时机是item出现（或将要出现）在屏幕上时，这时需要向传入的viewHolder中填充数据等

@Override
public void onBindViewHolder(MyViewHolder myViewHolder, final int i) 
{
    MyCellClass cellClass = cellList.get(i);
    myViewHolder.tv.setText(cellClass.text);
    myViewHolder.iv.setImageResource(cellClass.image);
}

<a name="getItemCount">getItemCount函数</a>getItemCount返回子布局数量 可以给一个cellList.size()的返回值

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

子布局点击事件：

可以通过在onBindViewHolder中使用myViewHolder.itemView.setOnClickListener的方式添加

如果想在onClick中获取点击的子布局的index

• 将onBindViewHolder的参数int i设置为final，这样onClick就可以使用i
• 给MyRecycleAdapter设置接口，再编写逻辑代码

适配器所有代码在末尾

在Activity中设置RecycleView和适配器：

adapter = new MyRecycleAdapter(getApplicationContext());
rv.setAdapter(adapter);
gridLayoutManager = new GridLayoutManager(getApplicationContext(), 4);//(Context,spanCount)
rv.setLayoutManager(gridLayoutManager);

<a name="end"></a>

public class MyRecycleAdapter extends aRecyclerView.Adapter<MyViewHolder>{
    private LinkedList<MyCellClass> cellList = new LinkedList<>();
    private Context context;
    private LayoutInflater mInflater;
    private final static String TAG = "MyRecycleAdapter";
    public MyRecycleAdapter(Context context) {
        cellList.add(new MyCellClass("1",R.drawable.icon_computer));
        cellList.add(new MyCellClass("1",R.drawable.icon_computer));
        cellList.add(new MyCellClass("1",R.drawable.icon_computer));
        cellList.add(new MyCellClass("1",R.drawable.icon_computer));
        cellList.add(new MyCellClass("1",R.drawable.icon_computer));
        
        this.context = context;
        mInflater = LayoutInflater.from(context);
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
        View view = mInflater.inflate(R.layout.ceil_layout,viewGroup,false);
        MyViewHolder myViewHolder = new MyViewHolder(view);
        return myViewHolder;
    }

    @Override
    public void onBindViewHolder(MyViewHolder myViewHolder, final int i) {
        MyCellClass cellClass = cellList.get(i);
        myViewHolder.tv.setText(cellClass.text);
        myViewHolder.iv.setImageResource(cellClass.image);

        myViewHolder.itemView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Log.i(TAG,"  This is :" + i);
            }
        });
    }
    
    @Override
    public int getItemCount() {
        return cellList.size();
    }
}