ListView와 같이 데용량의 데이터를 한정된 화면에 보여주기 위한 클래스이다.
- LayoutManager를 사용하여 ChildView를 더욱 자유롭게 배치할 수 있음
- Adapter를 통해 RecyclerView에 데이터를 공급하고 View를 가공
- ChildView를 생성하고 내용을 구성하는 기능을 ViewHolder를 통해 구현
1. 모듈의 dependencies에 recyclerview-v7를 추가
File > Project Structure 선택 후 팝업의 좌측 Modules에서 사용할 모듈 선택
우측에서 Dependencies 탭을 선택한 후 +버튼을 클릭하고 com.android.support:recyclerview를 검색하여 추가
혹은, 모듈의 gradle 파일에 직접 입력해도 됨
dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) compile 'com.android.support:appcompat-v7:24.2.1' compile 'com.android.support:recyclerview-v7:24.2.1' }
2. Layout에 RecyclerView 배치
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/activity_recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="@dimen/activity_horizontal_margin"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
android:orientation="vertical"
tools:context="com.jiyoung.andstudy.activity.RecyclerViewActivity">
....
<android.support.v7.widget.RecyclerView
android:id="@+id/recycler_view"
android:layout_width="match_parent"
android:layout_height="match_parent" />
....
</LinearLayout>
3. ChildView의 Layout 만들기
CardView를 이용해서 이쁘게 만들어 봄 ㅎㅎ (com.android.support:cardview-v7 라이브러리 추가)
CardView는 모서리를 둥글게 하는 속성 (cardCornerRadius), 그림자 속성 (cardElevation) 등을 기능을 지원한다.
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:card_view="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
card_view:cardCornerRadius="12dp"
card_view:cardElevation="5dp"
card_view:contentPadding="10dp">
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<ImageView
android:id="@+id/img_thumb"
android:layout_width="130dp"
android:layout_height="130dp"
android:layout_marginRight="5dp"
android:src="@drawable/sample_0"
android:scaleType="centerCrop"/>
<TextView
android:id="@+id/tv_title"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/img_thumb"
android:layout_marginBottom="5dp"
android:lines="1"
android:ellipsize="end"
android:textSize="18dp"
android:text="Title"
/>
<TextView
android:id="@+id/tv_desc"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_toRightOf="@id/img_thumb"
android:layout_below="@id/tv_title"
android:textSize="13dp"
android:text="description"/>
</RelativeLayout>
</android.support.v7.widget.CardView>
4. ViewHolder 구현
위의 ChildView를 생성하고, 데이터를 설정할 ViewHolder를 생성한다.
public class CardViewHolder extends RecyclerView.ViewHolder {
ImageView imgThumb;
TextView tvTitle;
TextView tvDesc;
ChapterInfo chapterInfo;
public CardViewHolder(View itemView) {
super(itemView);
imgThumb = (ImageView) itemView.findViewById(R.id.img_thumb);
tvTitle = (TextView) itemView.findViewById(R.id.tv_title);
tvDesc = (TextView) itemView.findViewById(R.id.tv_desc);
}
public void setChapterInfo(ChapterInfo chapterInfo) {
this.chapterInfo = chapterInfo;
imgThumb.setImageDrawable(chapterInfo.getImage());
tvTitle.setText(chapterInfo.getTitle());
tvDesc.setText(chapterInfo.getDescription());
}
}
5. Adapter 구현
데이터를 받아 ViewHolder를 생성하는 Adapter를 구현
public class RecyclerChapterAdapter extends RecyclerView.Adapter<CardViewHolder> {
List<ChapterInfo> items = new ArrayList<ChapterInfo>();
Context mContext;
public RecyclerChapterAdapter(Context context) {
this.mContext = context;
items.add(new ChapterInfo(context.getResources().getDrawable(R.drawable.sample_0), "TEST0", "this is test1. this is test1. this is test1. this is test1."));
items.add(new ChapterInfo(context.getResources().getDrawable(R.drawable.sample_1), "TEST1", "this is test1. this is test1. this is test1. this is test1."));
items.add(new ChapterInfo(context.getResources().getDrawable(R.drawable.sample_2), "TEST2", "this is test1. this is test1. this is test1. this is test1."));
items.add(new ChapterInfo(context.getResources().getDrawable(R.drawable.sample_3), "TEST3", "this is test1. this is test1. this is test1. this is test1."));
}
@Override
public CardViewHolder onCreateViewHolder(ViewGroup viewGroup, int viewType) {
View view = LayoutInflater.from(viewGroup.getContext())
.inflate(R.layout.item_card_view, viewGroup, false);
return new CardViewHolder(view);
}
@Override
public void onBindViewHolder(CardViewHolder holder, int position) {
holder.setChapterInfo(items.get(position));
}
@Override
public int getItemCount() {
return items.size();
}
}
6. RecyclerView에 Adapter 적용
public class RecyclerViewActivity extends AppCompatActivity {
RecyclerView recyclerView;
RecyclerView.LayoutManager layoutManager;
RecyclerView.Adapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recycler_view);
recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
layoutManager = new LinearLayoutManager(this);
recyclerView.setLayoutManager(layoutManager);
adapter = new RecyclerChapterAdapter(this);
recyclerView.setAdapter(adapter);
}
}