RecyclerView的使用

Recyclerview

RecyclerView是ListView的升级版，不仅可以轻松实现Listview同样的效果，还优化了ListView中的各种不足；
打开build.gradle

compile 'com.android.support:recyclerview-v7:25.3.1'

main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:layout_height="wrap_content">
    <android.support.v7.widget.RecyclerView
        android:id="@+id/recycler_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</LinearLayout>
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recyelerview_item.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="100dp"
    android:layout_height="wrap_content"
    android:orientation="vertical">
    <ImageView
        android:id="@+id/fruit_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <TextView
        android:layout_marginTop="10dp"
        android:id="@+id/fruit_name"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

布局文件其实都跟我们的ListView的文件差不多，重要的是适配器，以及它的拓展性强，下面来看我们的Java代码

public class FruitAdapter extends RecyclerView.Adapter<FruitAdapter.ViewHolder>{
    private List<Fruit> mFruitList;
    static class ViewHolder extends RecyclerView.ViewHolder {
        View fruitView;
        ImageView fruitImage;
        TextView fruitName;
        public ViewHolder(View view) {
            super(view);
            fruitView = view;
            fruitImage = (ImageView) view.findViewById(R.id.fruit_image);
            fruitName = (TextView) view.findViewById(R.id.fruit_name);
        }
    }
    public FruitAdapter(List<Fruit> fruitList){
        mFruitList = fruitList;
    }
    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.recycler_item,parent,false);
        final RecyclerView.ViewHolder holder = new ViewHolder(view);
        return (ViewHolder) holder;
    }
    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        final Fruit fruit = mFruitList.get(position);
        holder.fruitImage.setImageResource(fruit.getImageId());
        holder.fruitName.setText(fruit.getName());
        holder.fruitView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int position = holder.getAdapterPosition();
                Fruit fruit1 = mFruitList.get(position);
                Toast.makeText(v.getContext(),"you click view"+fruit.getName(),Toast.LENGTH_SHORT).show();
            }
        });
        holder.fruitImage.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                int position = holder.getAdapterPosition();
                Fruit fruit1 = mFruitList.get(position);
                Toast.makeText(v.getContext(),"you click view"+fruit.getName(),Toast.LENGTH_SHORT).show();
            }
        });
    }
    @Override
    public int getItemCount() {
        return mFruitList.size();
    }
}

你们可能会说这那里简单，比我们的ListView的代码多多了。但是仔细看，你会发现它的代码逻辑通俗易懂。

MainActivity.java
public class MainActivity extends AppCompatActivity {
    private List<Fruit> fruitList = new ArrayList<>();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initFruit();
        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        //设置RecyclerView的滑动方向
        layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
        recyclerView.setLayoutManager(layoutManager);
        FruitAdapter adapter = new FruitAdapter(fruitList);
        recyclerView.setAdapter(adapter);
    }
    private void initFruit() {
        Fruit fruit1 = new Fruit("1",R.mipmap.ic_launcher);
        Fruit fruit2 = new Fruit("2",R.mipmap.ic_launcher);
        Fruit fruit3 = new Fruit("3",R.mipmap.ic_launcher);
        Fruit fruit4 = new Fruit("4",R.mipmap.ic_launcher);
        Fruit fruit5 = new Fruit("5",R.mipmap.ic_launcher);
        Fruit fruit6 = new Fruit("6",R.mipmap.ic_launcher);
        Fruit fruit7 = new Fruit("7",R.mipmap.ic_launcher);
        Fruit fruit8 = new Fruit("9",R.mipmap.ic_launcher);
        fruitList.add(fruit1);
        fruitList.add(fruit2);
        fruitList.add(fruit3);
        fruitList.add(fruit4);
        fruitList.add(fruit5);
        fruitList.add(fruit6);
        fruitList.add(fruit7);
        fruitList.add(fruit8);
    }


细心的你可能发现
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL);
跟我们的ListView的中的差别很大
这就是RecyclerView的神奇之处，它能根据我们的需要，来横向滑动或者纵向活动；
还可以设置成GridView的模式，是不是很神奇。
下次再具体讲讲，RecyclerView设置成Gridview

源码下载