Android RecyclerView初探

原文:https://github.com/dyguests/RecyclerViewDemo

RecyclerView是用于替换ListView的解决方案，将视图控制和数据绑定做了分离，提供了强大的样式定制能力

使用教程

1.准备工作

在 module 的 build.gradle 中 加入 compile 'com.android.support:recyclerview-v7:23.3.0' 代码:

dependencies {
    ...
    compile 'com.android.support:recyclerview-v7:23.3.0'//1.1
    ...
}

2.使用RecyclerView

2.1.在xml中添加RecyclerView

activity_linear_layout_manager.xml

<RelativeLayout
    ...>
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        tools:listitem="@layout/item_linear"/>
</RelativeLayout>

注:tools:listitem="@layout/item_linear"是用于在Android Studio的Preview中查看效果用的

2.2.在java中添加RecyclerView

LinearLayoutManagerActivity.java

2.2.1.绑定

mRecyclerView = ((RecyclerView) findViewById(R.id.recycler_view));

2.2.2.添加LayoutManager(布局方式)

mRecyclerView.setLayoutManager(new LinearLayoutManager(this,
                LinearLayoutManager.VERTICAL/*方向*/,
                false/*是否反向*/
        ));

注:这里用LinearLayoutManager表示这是使用线性布局,也可以使用GridLayoutManager等.

2.2.3.绑定Adapter(参考 2.3.创建Adapter)

mAdapter = new LinearLayoutManagerAdapter(this);
        mRecyclerView.setAdapter(mAdapter);

2.2.4.添加数据

...
mAdapter.addItem(user);
...

也可以使用

...
mAdapter.addItems(users);
...

注:addItem(),addItems()方法是自定义的,主要是为了把数据添加操作和动画放在一起.

2.3.创建Adapter

2.3.1.创建LinearLayoutManagerAdapter类

public class LinearLayoutManagerAdapter{

}

2.3.2.让类继承RecyclerView.Adapter

public class LinearLayoutManagerAdapter extends RecyclerView.Adapter{

}

2.3.3.注意,RecyclerView.Adapter是泛型类,需要一个继承至RecyclerView.ViewHolder的泛型参数(?),这里我们创建一个ViewHolder的内部类:

public class LinearLayoutManagerAdapter extends RecyclerView.Adapter{

    public class ViewHolder extends RecyclerView.ViewHolder{

    }
}

2.3.4.添加泛型声明

public class LinearLayoutManagerAdapter extends RecyclerView.Adapter<LinearLayoutManagerAdapter.ViewHolder>{

    public class ViewHolder extends RecyclerView.ViewHolder{

    }
}

2.3.5.实现方法

public class LinearLayoutManagerAdapter extends RecyclerView.Adapter<LinearLayoutManagerAdapter.ViewHolder>{

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return null;
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {

    }

    @Override
    public int getItemCount() {
        return 0;
    }

    public class ViewHolder extends RecyclerView.ViewHolder{

        public ViewHolder(View itemView) {
            super(itemView);
        }
    }
}

2.3.6.添加构造器

public class LinearLayoutManagerAdapter extends RecyclerView.Adapter<LinearLayoutManagerAdapter.ViewHolder>{

    private final Context context;

    public LinearLayoutManagerAdapter(Context context) {
        this.context = context;
    }

    ...
}

2.3.7.指定item_view,注意这里与ListView不同,这里不返回View,而是返回ViewHolder(自已定义的).

@Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(context).inflate(R.layout.item_linear, parent, false);
        return new ViewHolder(view);
    }

2.3.8.添加数据源

public class LinearLayoutManagerAdapter extends RecyclerView.Adapter<LinearLayoutManagerAdapter.ViewHolder>{
    ...
    private final ArrayList<User> list;


    public LinearLayoutManagerAdapter(Context context) {
        this.context = context;
        list = new ArrayList<>();
    }
    ...
    @Override
    public int getItemCount() {
        return list.size();
    }
    ...
}

2.3.9.实现list_item与数据的绑定

public class LinearLayoutManagerAdapter extends RecyclerView.Adapter<LinearLayoutManagerAdapter.ViewHolder>{
    ...
    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.bind(list.get(position));
    }
    ...
    public class ViewHolder extends RecyclerView.ViewHolder{
        ...
        public void bind(User data) {
        }
    }
}

2.3.10.在ViewHolder中实现布局元素的绑定与数据的绑定

public class ViewHolder extends RecyclerView.ViewHolder {
        private final TextView mTextView;
        private       User     data;

        public ViewHolder(View itemView) {
            super(itemView);
            mTextView = ((TextView) itemView.findViewById(R.id.text_view));
        }

        public void bind(User data) {
            mTextView.setText(data.getName());

            this.data = data;
        }
    }

这里注意一下,请尽量把ViewHolder相关的布局元素绑定,数据绑定放到ViewHolder中来实现,而不要放到onCreateViewHolder(),onBindViewHolder()中去实现.

2.3.11.其它相关代码

    //-----------------------数据增删相关-------------------------------

    public void addItem(User item) {
        int positionStart = list.size();
        list.add(item);
        notifyItemInserted(positionStart);
    }

    public void addItems(List<User> items) {
        int positionStart = list.size();
        list.addAll(items);
        notifyItemRangeInserted(positionStart, items.size());
    }

    public void clear() {
        int itemCount = list.size();
        list.clear();
        notifyItemRangeRemoved(0, itemCount);
    }

注:这段代码是为了方便把数据增删和动画效果绑定要一起

3.其它几种例子

LinearLayoutManagerActivity

GridLayoutManagerActivity

InContainerActivity