[Android]RecyclerView基本使用+adapter回撥介面實現點選事件
阿新 • • 發佈：2018-12-24
一、概述
RrcyclerView是ListView的加強版，不僅可以輕鬆實現和ListView同樣的效果，還優化了ListView中存在的各種不同之處。
Android官方推薦我們使用RecyclerView。
二、基本用法
1.首先需要在專案的build.gradle中新增相應的依賴庫：
implementation 'com.android.support:recyclerview-v7:27.1.1'2.在layout佈局中新增RecyclerView空間：activity_list_view.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <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> </LinearLayout>
3.新建Adapter介面卡：FruitRecyclerAdapter.java
public class FruitRecyclerAdapter extends RecyclerView.Adapter<FruitRecyclerAdapter.ViewHolder> { //資料來源 private List<Fruit> mFruitList; public FruitRecyclerAdapter(List<Fruit> mFruitList) { this.mFruitList = mFruitList; } //自定義內部類 ViewHolder public static class ViewHolder extends RecyclerView.ViewHolder { ImageView fruitImage; TextView fruitName; Button button; LinearLayout itemDetail; public ViewHolder(View itemView) { super(itemView); fruitImage = (ImageView) itemView.findViewById(R.id.fruit_image); fruitName = (TextView) itemView.findViewById(R.id.fruit_name); button = (Button) itemView.findViewById(R.id.fruit_button); itemDetail = (LinearLayout) itemView.findViewById(R.id.item_detail); } } //用於建立ViewHolder例項，並載入佈局 @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit_item, parent, false); ViewHolder holder = new ViewHolder(view); return holder; } //對RecyclerView子項資料進行賦值 @Override public void onBindViewHolder(ViewHolder holder, final int position) { Fruit fruit = mFruitList.get(position); holder.fruitImage.setImageResource(fruit.getImageId()); holder.fruitName.setText(fruit.getName()); } //RecyclerView子項的個數 @Override public int getItemCount() { return mFruitList.size(); } }
4. 新建item子佈局layout：fruit_item.xml
- 新建介面卡類要繼承RecyclerView.Adapter<...>，繼承的泛型ViewHolder需要我們自己新建內部類ViewHolder。
- 內部類ViewHolder,繼承RecyclerView.ViewHolder。
- 新建建構函式，初始化資料來源list。
- 因為繼承了RecyclerView.Adapter,所以要重寫onCreateViewHolder()、onBindViewHolder()、getItemCount()三個方法。
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/item_detail" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_margin="5dp" android:background="@drawable/border" android:orientation="vertical"> <ImageView android:id="@+id/fruit_image" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" /> <Button android:id="@+id/fruit_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:text="點選" /> <TextView android:id="@+id/fruit_name" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_gravity="center_horizontal" android:layout_marginStart="10dp" /> </LinearLayout>
5.activity對RecyclerView的處理：
recyclerView = (RecyclerView) findViewById(R.id.recycle_view);
LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
recyclerView.setLayoutManager(layoutManager);
adapter = new FruitRecyclerAdapter(fruitList);
recyclerView.setAdapter(adapter);layoutmanager用於指定RecyclerView的佈局方式：
- LinearLayoutManager.VERTICAL ：線性垂直
- LinearLayoutManager.HORIZONTAL：線性水平
- GridLayoutManager.VERTICAL ：網格垂直
- GridLayoutManager.HORIZONTAL：網格水平
- StaggeredGridLayoutManager.VERTICAL：瀑布流
獲取adapter例項，並傳入資料來源list。最後呼叫RecyclerView的setAdapter()方法。
到此RecyclerView和資料之間的關聯就建立好了。
三、新增點選事件
大多數情況下，我們需要實現每個item本身或者item中的button等控制元件的點選事件。就需要在adapter中用到介面回撥，
添加了介面回撥的adapter程式碼如下：
public class FruitRecyclerAdapter extends RecyclerView.Adapter<FruitRecyclerAdapter.ViewHolder> {
//資料來源
private List<Fruit> mFruitList;
//介面
private ClickInterface clickInterface;
public FruitRecyclerAdapter(List<Fruit> mFruitList) {
this.mFruitList = mFruitList;
}
//--------------------點選事件-------------------------------------------//
public void setOnclick(ClickInterface clickInterface) {
this.clickInterface = clickInterface;
}
//回撥介面
public interface ClickInterface {
void onButtonClick(View view, int position);
void onItemClick(View view, int position);
}
//--------------------點選事件-------------------------------------------//
//自定義內部類 ViewHolder
public static class ViewHolder extends RecyclerView.ViewHolder {
ImageView fruitImage;
TextView fruitName;
Button button;
LinearLayout itemDetail;
public ViewHolder(View itemView) {
super(itemView);
fruitImage = (ImageView) itemView.findViewById(R.id.fruit_image);
fruitName = (TextView) itemView.findViewById(R.id.fruit_name);
button = (Button) itemView.findViewById(R.id.fruit_button);
itemDetail = (LinearLayout) itemView.findViewById(R.id.item_detail);
}
}
//用於建立ViewHolder例項，並載入佈局
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.fruit_item, parent, false);
ViewHolder holder = new ViewHolder(view);
return holder;
}
//對RecyclerView子項資料進行賦值
@Override
public void onBindViewHolder(ViewHolder holder, final int position) {
Fruit fruit = mFruitList.get(position);
holder.fruitImage.setImageResource(fruit.getImageId());
holder.fruitName.setText(fruit.getName());
//--------------------點選事件-------------------------------------------//
//Button點選事件
holder.button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clickInterface != null) {
clickInterface.onButtonClick(v, position);
}
}
});
//item點選事件
holder.itemDetail.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clickInterface != null) {
clickInterface.onItemClick(v, position);
}
}
});
//--------------------點選事件-------------------------------------------//
}
//RecyclerView子項的個數
@Override
public int getItemCount() {
return mFruitList.size();
}
}
Activity程式碼中的點選事件處理：
recyclerView = (RecyclerView) findViewById(R.id.recycle_view);
LinearLayoutManager layoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
recyclerView.setLayoutManager(layoutManager);
adapter = new FruitRecyclerAdapter(fruitList);
recyclerView.setAdapter(adapter);
//新增點選事件
recyclerView.post(new Runnable() {
@Override
public void run() {
adapter.setOnclick(new FruitRecyclerAdapter.ClickInterface() {
@Override
public void onButtonClick(View view, int position) {
Toast.makeText(view.getContext(), "Click Button - position: " + position + " name: " + fruitList.get(position).getName(), Toast.LENGTH_SHORT).show();
}
@Override
public void onItemClick(View view, int position) {
Toast.makeText(view.getContext(), "Click Item Detail - position: " + position + " name: " + fruitList.get(position).getName(), Toast.LENGTH_SHORT).show();
}
});
}
});這裡實現了item和button的兩個點選事件。
END.