RecycleView的實現

實現效果圖:

RecycleView的實現步驟:
1.搭建環境:由於RecycleView是在android5.0之後出來的,用來代替listview,以前的版本能用。需要添加包

選擇recycleview-v7包


2.佈局文件添加recycleview
<android.support.v7.widget.RecyclerView
        android:id="@+id/recycle_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        
    </android.support.v7.widget.RecyclerView>
3.實例化RecycleView控件


4.創建DataBean類,存放bean屬性

5.創建LoadListData()方法,給RecycleView填充數據
    private void LoadListData() {
        //集合對象
        ArrayList<DataBean> list = new ArrayList<>();
        //給Bean類放數據,最後把裝好數據的Bean類放到集合裏
        for(int i=0;i<35;i++){
            //創建Bean類對象,
            DataBean bean = new DataBean();
            bean.icon = R.drawable.animal01;
            bean.name = "dog"+i;
            //把Bean類放入集合裏
            list.add(bean);
        }
    }
6.在主方法中調用LoadListData()方法;

7.創建MyRecycleAdapter適配器,並配置
(1)創建適配器Myadapter繼承自RecyclerView.Adapter<Myadapter.listViewHolder>,並實現內部的方法;

(2)在適配器中創建構造方法:

(3)在實現的public MyRecycleAdapter.ListViewHolder onCreateViewHolder(ViewGroup parent, int viewType) 方法中創建ViewHolder,並把ViewHolder返回出去,
①先轉換一個View佈局,決定了item的樣子, 參數:1.上下文 2.Xml佈局資源 3.爲null,
View view = View.inflate(mContext, R.layout.item, null);
②創建item佈局

item佈局代碼:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:layout_width="match_parent"
              android:layout_height="match_parent">
    <ImageView
        android:id="@+id/item_iv_icon"
        android:layout_width="75dp"
        android:layout_height="75dp"/>
    <TextView
        android:layout_centerVertical="true"
        android:layout_toRightOf="@+id/item_iv_icon"
        android:textSize="30sp"
        android:id="@+id/item_tv_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"/>
</RelativeLayout>
③創建ViewHolder,並把ViewHolder返回出去
代碼:public MyRecycleAdapter.ListViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //轉換一個View佈局,決定了item的樣子, 參數:1.上下文 2.Xml佈局資源 3.爲null
        View view = View.inflate(mContext, R.layout.item, null);
        //創建一個ViewHolder對象
        ListViewHolder listViewHolder = new ListViewHolder(view);
        //把VIewHolder對象傳出去
        return listViewHolder;
    }
(4)當VIewHolder和數據綁定時回調
代碼:public void onBindViewHolder(ListViewHolder holder, int position) {
        //從集合裏拿對應item數據對象
        DataBean dataBean = mDataBeen.get(position);
        //給holder裏面的控件對象設置數據
        holder.setData(dataBean);
    }
(5)決定RecycleView有多少條item
代碼:public int getItemCount() {
        //數據不爲空,有幾條數據就顯示幾條數據
        if(list!=null&&list.size()>0){
return list.size();
        }
        return 0;


(6)配置自動幫我們寫的ViewHolder,參數View佈局對象
代碼:
public class ListViewHolder extends RecyclerView.ViewHolder {


        private final ImageView mIcon;
        private final TextView mTextView;


        public ListViewHolder(View itemView) {
            super(itemView);
            mIcon = (ImageView)itemView.findViewById(R.id.item_iv_icon);
            mTextView = (TextView) itemView.findViewById(R.id.item_tv_text);
        }


        public void setData(DataBean data) {
            //給ImageView設置圖片數據
            mIcon.setImageResource(data.icon);
            //給TextView設置文本數據
            mTextView.setText(data.name);
        }
    } 
8.創建適配器MyRecycleAdapter對象 參數:1.上下文2.數據加載集合;
 MyRecycleAdapter adapter = new MyRecycleAdapter(this,list);
9.設置適配器
        recyclerView.setAdapter(adapter);
10.佈局管理器所需參數, 上下文
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
11.設置佈局管理器,參數linearLayoutManager對象

        recyclerView.setLayoutManager(linearLayoutManager);

MainAcitivity代碼:

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        recyclerView = (RecyclerView) findViewById(R.id.recycle_view);
 LoadListData();
    }

    private void LoadListData() {
        //集合對象
        ArrayList<DataBean> list = new ArrayList<>();
        //給Bean類放數據,最後把裝好數據的Bean類放到集合裏
        for(int i=0;i<35;i++){
            //創建Bean類對象,
            DataBean bean = new DataBean();
            bean.icon = R.drawable.animal01;
            bean.name = "dog"+i;
            //把Bean類放入集合裏
            list.add(bean);
        }
        //創建適配器Adapter對象  參數:1.上下文2.數據加載集合
        MyRecycleAdapter adapter = new MyRecycleAdapter(this,list);
        //設置適配器
        recyclerView.setAdapter(adapter);
        //佈局管理器所需參數, 上下文
        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(this);
        //設置佈局管理器,參數linearLayoutManager對象
        recyclerView.setLayoutManager(linearLayoutManager);
    }
}
MyRecycleAdapterdaima :
//RecycleView的適配器,要注意指定的泛型,一般我們就是類名的ViewHolder繼承ViewHolder(內部已經實現了複用優化機制)
public class MyRecycleAdapter extends RecyclerView.Adapter<MyRecycleAdapter.ListViewHolder>{
    private Context mContext;
    //泛型是RecycleView所需的bean類
    private List<DataBean>list;
    //創建構造方法;一個需要接受兩個參數,上下文,集合對象(包含了我們所需要的數據)
    public MyRecycleAdapter(Context context, List<DataBean> list) {
        mContext = context;
        this.list = list;
    }

    @Override
    //創建ViewHolder,並把ViewHolder返回出去
    public MyRecycleAdapter.ListViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        //轉換一個View佈局,決定了item的樣子, 參數:1.上下文 2.Xml佈局資源 3.爲null
        View view = View.inflate(mContext, R.layout.item, null);
        //創建一個ViewHolder對象
        ListViewHolder listViewHolder = new ListViewHolder(view);
        //把VIewHolder對象傳出去
        return listViewHolder;
    }

    @Override
    //當VIewHolder和數據綁定時回調
    public void onBindViewHolder(MyRecycleAdapter.ListViewHolder holder, int position) {
        //從集合裏拿對應item數據對象
        DataBean dataBean = list.get(position);
        //給Holder裏面的控件對象設置數據
        holder.setData(dataBean);
    }

    @Override
    //決定RecycleView有多少條item
    public int getItemCount() {
        if(list!=null&&list.size()>0){
            return list.size();
        }
        return 0;
    }

    public class ListViewHolder extends RecyclerView.ViewHolder {

        private final ImageView mIcon;
        private final TextView mTextView;

        public ListViewHolder(View itemView) {
            super(itemView);
            mIcon = (ImageView)itemView.findViewById(R.id.item_iv_icon);
            mTextView = (TextView) itemView.findViewById(R.id.item_tv_text);
        }

        public void setData(DataBean data) {
            //給ImageView設置圖片數據
            mIcon.setImageResource(data.icon);
            //給TextView設置文本數據
            mTextView.setText(data.name);
        }
    }
}


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