Android RecyclerView的使用（四）——点击事件

前言： RecyclerView提供了一种插拔式的体验，高度的解耦，异常的灵活，通过设置它提供的不同LayoutManager，ItemDecoration , ItemAnimator实现绚丽的效果。

• 通过布局管理器LayoutManager，可以控制其显示的方式；
• 通过ItemDecoration，可以控制Item间的间隔（可定制）；
• 通过ItemAnimator，可以控制Item增删的动画；
• 至于点击、长按事件，RecyclerView并没有给我们提供相应的方法接口，需要我们自己实现。

上一节我们了解了如何通过RecyclerView 实现瀑布流，本节我们将学习如何为我们的Item添加点击事件。

效果图：

1、布局文件

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout 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:layout_height="match_parent">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>

</android.support.constraint.ConstraintLayout>
           

2、定义item的样式

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:background="@drawable/item_bg"
    android:layout_margin="3dp"
    android:layout_height="72dp">

    <ImageView
        android:id="@+id/imageView"
        android:layout_margin="20dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

    <TextView
        android:id="@+id/textView"
        android:layout_gravity="center_vertical"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />

</LinearLayout>
           

3、自定义的Adapter适配器，添加item click接口，设置item的点击事件。

public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {

    private LayoutInflater mInflater;
    private Context mContext;
    private List<String> mDatas;
    private int[] imgIds;

    private OnItemClickListener mOnItemClickListener;

    public MyAdapter(Context context, List<String> datas, int[] imgIds) {
        this.mContext = context;
        this.mDatas = datas;
        this.imgIds = imgIds;
        mInflater = LayoutInflater.from(context);
    }

    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.item_single_textview, parent, false);
        MyViewHolder viewHolder = new MyViewHolder(view);
        return viewHolder;
    }

    @Override
    public void onBindViewHolder(final MyViewHolder holder, final int position) {
        holder.textView.setText(mDatas.get(position));
        holder.imageView.setBackgroundResource(imgIds[ position % imgIds.length]);

        // item click
        if (mOnItemClickListener != null) {
            holder.itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    mOnItemClickListener.onItemClick(holder.itemView, position);
                }
            });
        }

        // item long click
        holder.itemView.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
                mOnItemClickListener.onItemLongClick(holder.itemView, position);
                return true;
            }
        });
    }

    @Override
    public int getItemCount() {
        return mDatas.size();
    }

    public void setOnItemClickListener(OnItemClickListener listener) {
        this.mOnItemClickListener = listener;
    }

    public void addData(int pos) {
        mDatas.add(pos, "Add one");
        notifyItemInserted(pos);
    }

    public void deleteData(int pos) {
        mDatas.remove(pos);
        notifyItemRemoved(pos);
    }

    public interface OnItemClickListener {
        void onItemClick(View view, int position);
        void onItemLongClick(View view, int position);
    }
}
class MyViewHolder extends RecyclerView.ViewHolder {

    ImageView imageView;
    TextView textView;

    public MyViewHolder(View itemView) {
        super(itemView);
        textView = itemView.findViewById(R.id.textView);
        imageView = itemView.findViewById(R.id.imageView);
    }
}
           

4、MainActivity.java

public class MainActivity extends AppCompatActivity {

    private RecyclerView recyclerView;

    private List<String> mDatas;
    private int[] imgIds;
    private MyAdapter mAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        initDatas();

        recyclerView = (RecyclerView) findViewById(R.id.recyclerView);

        mAdapter = new MyAdapter(this, mDatas, imgIds);
        recyclerView.setAdapter(mAdapter);

        //设置RecyclerView的布局管理
        LinearLayoutManager manager = new LinearLayoutManager(this,
                LinearLayoutManager.VERTICAL, false);
        recyclerView.setLayoutManager(manager);

        recyclerView.setItemAnimator(new DefaultItemAnimator());

        mAdapter.setOnItemClickListener(new MyAdapter.OnItemClickListener() {
            @Override
            public void onItemClick(View view, int position) {
                Toast.makeText(MainActivity.this, "clicked " + position,
                        Toast.LENGTH_SHORT).show();
            }

            @Override
            public void onItemLongClick(View view, int position) {
                Toast.makeText(MainActivity.this, "long clicked " + position,
                        Toast.LENGTH_SHORT).show();
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case R.id.add:
                mAdapter.addData();
                break;
            case R.id.delete:
                mAdapter.deleteData();
                break;
            case R.id.listView:
                recyclerView.setLayoutManager(new LinearLayoutManager(MainActivity.this));
                break;
            case R.id.gridView:
                recyclerView.setLayoutManager(new GridLayoutManager(MainActivity.this, ));
                break;
            case R.id.gridView_hor:
                recyclerView.setLayoutManager(new StaggeredGridLayoutManager(,
                        StaggeredGridLayoutManager.HORIZONTAL));
                break;
            case R.id.staggered:
                Intent intent = new Intent(this, StaggeredActivity.class);
                startActivity(intent);
                break;
            default:
                break;
        }
        return super.onOptionsItemSelected(item);
    }

    private void initDatas() {
        imgIds = new int[]{R.mipmap.pic01, R.mipmap.pic02, R.mipmap.pic03, R.mipmap.pic04,
                R.mipmap.pic05, R.mipmap.pic06, R.mipmap.pic07};
        mDatas = new ArrayList<>();
        mDatas.add("亳州"); 
        mDatas.add("大娃");
        mDatas.add("二娃");
        mDatas.add("三娃");
        mDatas.add("四娃");
        mDatas.add("五娃");
        mDatas.add("六娃");
        mDatas.add("七娃");
        mDatas.add("喜羊羊");
        mDatas.add("美羊羊");
        mDatas.add("懒羊羊");
        mDatas.add("沸羊羊");
        mDatas.add("暖羊羊");
        mDatas.add("慢羊羊");
        mDatas.add("灰太狼");
        mDatas.add("红太狼");
        mDatas.add("孙悟空");
        mDatas.add("黑猫警长");
        mDatas.add("舒克");
        mDatas.add("贝塔");
        mDatas.add("海尔");
        mDatas.add("阿凡提");
        mDatas.add("邋遢大王");
        mDatas.add("哪吒");
        mDatas.add("没头脑");
        mDatas.add("不高兴");
        mDatas.add("蓝皮鼠");
        mDatas.add("大脸猫");
        mDatas.add("大头儿子");
        mDatas.add("小头爸爸");
        mDatas.add("蓝猫");
        mDatas.add("淘气");
        mDatas.add("叶峰");
        mDatas.add("楚天歌");
        mDatas.add("江流儿");
        mDatas.add("Tom");
        mDatas.add("Jerry");
        mDatas.add("12345");
        mDatas.add("54321");
        mDatas.add("_(:з」∠)_");
        mDatas.add("……%￥#￥%#");
    }
}