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);

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)
    })

而不是实现接口视图。OnClickListener内部视图持有人或创建和接口和实现接口在您的活动.. 我使用这段代码简单的OnClickListener实现。

public static class SimpleStringRecyclerViewAdapter
            extends RecyclerView.Adapter<SimpleStringRecyclerViewAdapter.ViewHolder> {

        // Your initializations goes here...
        private List<String> mValues;

        public static class ViewHolder extends RecyclerView.ViewHolder {

            //create a variable mView
            public final View mView;

            /*All your row widgets goes here
            public final ImageView mImageView;
            public final TextView mTextView;*/

            public ViewHolder(View view) {
                super(view);
                //Initialize it here
                mView = view;

                /* your row widgets initializations goes here
                mImageView = (ImageView) view.findViewById(R.id.avatar);
                mTextView = (TextView) view.findViewById(android.R.id.text1);*/
            }
        }

        public String getValueAt(int position) {
            return mValues.get(position);
        }

        public SimpleStringRecyclerViewAdapter(Context context, List<String> items) {

            mBackground = mTypedValue.resourceId;
            mValues = items;
        }

        @Override
        public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.list_item, parent, false);
            view.setBackgroundResource(mBackground);
            return new ViewHolder(view);
        }

        @Override
        public void onBindViewHolder(final ViewHolder holder, int position) {
            holder.mBoundString = mValues.get(position);
            holder.mTextView.setText(mValues.get(position));

            //Here it is simply write onItemClick listener here
            holder.mView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Context context = v.getContext();
                    Intent intent = new Intent(context, ExampleActivity.class);

                    context.startActivity(intent);
                }
            });
        }

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

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()
    }
}

最简单的方法如下:

在Adapter类开始时声明全局变量:

// Store out here so we can resuse
private View yourItemView;

然后在onBindViewHolder方法中设置OnClickListener:

@Override
public void onBindViewHolder(BusinessAdapter.ViewHolder holder, int position) {

    // Set up the on click listener
    yourItemView.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            Toast.makeText(mContext,Integer.toString(position),Toast.LENGTH_SHORT).show();
        }
    });

}

其他答案都不正确。

如果您有一个pojo列表，并且希望从适配器外部单击检索一个pojo，那么这里有一种非常容易实现它的方法。

在你的适配器中，为点击事件创建一个监听器和一个方法来设置它:

public class MyAdapter extends RecyclerView.Adapter<SitesListAdapter.ViewHolder> {
...
private List<MyPojo> mMyPojos;
private static OnItemClickListener mOnItemClickListener;

...
public interface OnItemClickListener {
    public void onItemClick(MyPojo pojo);
}

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

}

在你的ViewHolder中，实现onClickListener并创建一个类成员来临时存储视图所呈现的POJO(这是一个例子，创建一个setter会更好):

public static class ViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
    public MyPojo mCurrentPojo;
    ...
    public ViewHolder(View view) {
        super(v);
        ...
        view.setOnClickListener(this); //You could set this on part of the layout too
    }

    ...
    @Override
    public void onClick(View view) {
        if(mOnItemClickListener != null && mCurrentPojo != null){
            mOnItemClickListener.onItemClick(mCurrentPojo);
        }
    }

回到你的适配器，当ViewHolder被绑定时设置当前POJO(如果当前视图没有，则设置为null):

@Override
public void onBindViewHolder(final ViewHolder holder, final int position) {
    final MyPojo currentPojo = mMyPojos.get(position); 
    holder.mCurrentPojo = currentPojo;
    ...

就是这样，现在你可以在你的fragment/activity中这样使用它:

    mMyAdapter.setOnItemClickListener(new mMyAdapter.OnItemClickListener() {
        @Override
        public void onItemClick(MyPojo pojo) {
            //Do whatever you want with your pojo here
        }
    });