RecyclerView是如何不同于Listview?

一个区别是有一个LayoutManager类和RecyclerView，通过它你可以像-一样管理你的RecyclerView

水平或垂直滚动线性layoutmanager GridLayout by GridLayoutManager 交错网格布局由StaggeredGridLayoutManager

就像水平滚动的RecyclerView-

LinearLayoutManager llm = new LinearLayoutManager(context);
llm.setOrientation(LinearLayoutManager.HORIZONTAL);
recyclerView.setLayoutManager(llm);

RecyclerView没有一个onItemClickListener，因为RecyclerView负责回收视图(惊讶!)，所以回收视图的责任是处理它接收到的点击事件。

这实际上使它更容易使用，特别是如果你有可以在多个地方点击的项目。

无论如何，检测点击一个RecyclerView项目是非常容易的。你所需要做的就是定义一个接口(如果你不使用Kotlin，在这种情况下你只需要传入一个lambda):

public class MyAdapter extends RecyclerView.Adapter<MyViewHolder> {
    private final Clicks clicks;

    public MyAdapter(Clicks clicks) {
        this.clicks = clicks;
    }

    private List<MyObject> items = Collections.emptyList();

    public void updateData(List<MyObject> items) {
        this.items = items;
        notifyDataSetChanged(); // TODO: use ListAdapter for diffing instead if you need animations
    }

    public interface Clicks {
        void onItemSelected(MyObject myObject, int position);
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {
        private MyObject myObject;    

        public MyViewHolder(View view) {
            super(view);
            // bind views
            view.setOnClickListener((v) -> {
                int adapterPosition = getBindingAdapterPosition();
                if(adapterPosition >= 0) {
                    clicks.onItemSelected(myObject, adapterPosition);
                }
            });
        }

        public void bind(MyObject myObject) {
            this.myObject = myObject;
            // bind data to views
        }
    }
}

Kotlin中的代码相同:

class MyAdapter(val itemClicks: (MyObject, Int) -> Unit): RecyclerView.Adapter<MyViewHolder>() {
    private var items: List<MyObject> = Collections.emptyList()

    fun updateData(items: List<MyObject>) {
        this.items = items
        notifyDataSetChanged() // TODO: use ListAdapter for diffing instead if you need animations
    }

    inner class MyViewHolder(val myView: View): RecyclerView.ViewHolder(myView) {
        private lateinit var myObject: MyObject

        init {
            // binds views
            myView.onClick {
                val adapterPosition = getBindingAdapterPosition()
                if(adapterPosition >= 0) {
                    itemClicks.invoke(myObject, adapterPosition)
                }
            }
        }

        fun bind(myObject: MyObject) {
            this.myObject = myObject
            // bind data to views
        }
    }
}

你不需要做的事情:

1)你不需要手动拦截触摸事件

2.)您不需要在子附加状态更改侦听器上添乱

3)你不需要RxJava中的PublishSubject/PublishRelay

只需使用点击侦听器。

Android Recyclerview与onItemClickListener， 为什么我们不能尝试这是工作像ListView。

来源:Link

public class RecyclerItemClickListener implements RecyclerView.OnItemTouchListener {

private OnItemClickListener mListener;
public interface OnItemClickListener {
    public void onItemClick(View view, int position);
}
GestureDetector mGestureDetector;
public RecyclerItemClickListener(Context context, OnItemClickListener listener) {
    mListener = listener;
    mGestureDetector = new GestureDetector(context, new GestureDetector.SimpleOnGestureListener() {
        @Override
        public boolean onSingleTapUp(MotionEvent e) {
            return true;
        }
    });
}
@Override
public boolean onInterceptTouchEvent(RecyclerView view, MotionEvent e) {
    View childView = view.findChildViewUnder(e.getX(), e.getY());
    if (childView != null && mListener != null && mGestureDetector.onTouchEvent(e)) {
        mListener.onItemClick(childView, view.getChildAdapterPosition(childView));
    }
    return false;
}

@Override
public void onTouchEvent(RecyclerView view, MotionEvent motionEvent) {
}

@Override
public void onRequestDisallowInterceptTouchEvent(boolean disallowIntercept) {

  }
}

并设置这个为RecyclerView:

    recyclerView = (RecyclerView)rootView. findViewById(R.id.recyclerView);
    RecyclerView.LayoutManager mLayoutManager = new            LinearLayoutManager(getActivity());
    recyclerView.setLayoutManager(mLayoutManager);
    recyclerView.addOnItemTouchListener(
            new RecyclerItemClickListener(getActivity(), new   RecyclerItemClickListener.OnItemClickListener() {
                @Override
                public void onItemClick(View view, int position) {
                    // TODO Handle item click
                    Log.e("@@@@@",""+position);
                }
            })
    );

跟进MLProgrammer-CiM的优秀RxJava解决方案

消费/观察点击

Consumer<String> mClickConsumer = new Consumer<String>() {
        @Override
        public void accept(@NonNull String element) throws Exception {
            Toast.makeText(getApplicationContext(), element +" was clicked", Toast.LENGTH_LONG).show();
        }
    };

ReactiveAdapter rxAdapter = new ReactiveAdapter();
rxAdapter.getPositionClicks().subscribe(mClickConsumer);

RxJava 2.+

将原tl;dr修改为:

public Observable<String> getPositionClicks(){
    return onClickSubject;
}

PublishSubject#asObservable()被移除。只需要返回PublishSubject，它是一个可观察对象。

我发现了使用androidx生命周期可变实时数据的最短方法之一

适配器:

private val onItemClickListener = MutableLiveData<YourAdapterItem>()


override fun onBindViewHolder(holder: GifsViewHolder, position: Int) {
    holder.itemView.setOnClickListener { onItemClickListener.value = gifs[position] }
}
fun getOnItemClickListener(): MutableLiveData<Gif> {
    return onItemClickListener
}

MainActivity的任何地方

    yourFancyAdapter.getOnItemClickListener().observe(this, Observer {
        println(it)
    })

这招对我很管用:

@Override
public void onBindViewHolder(PlacesListViewAdapter.ViewHolder holder, int position) {
    ----
    ----
    ----
    // Set setOnClickListener(holder);
}


@Override
public class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {

    ----
    ----
    ----

    @Override
    public void onClick(View view) {
        // Use to get the item clicked getAdapterPosition()
    }
}