RecyClerview加载更多最短和简单的方法？

Question

我想加载更多数据以显示10个数据加载后的回收视图。下面的示例。我很累。我无法理解解决方案。我想要一个简单的解决方案。

示例：

commentpost.java

 public void showData(){
    //view Comment
    progressDoalog = new ProgressDialog(CommentPost.this);
    progressDoalog.setMessage("Loading....");
    progressDoalog.show();
    /*Create handle for the RetrofitInstance interface*/
    Call<List<Comments>> call = service.getComment(audioPath);
    call.enqueue(new Callback<List<Comments>>() {
        @Override
        public void onResponse(Call<List<Comments>> call, Response<List<Comments>> response) {
            progressDoalog.dismiss();
            generateDataList(response.body());
        }
        @Override
        public void onFailure(Call<List<Comments>> call, Throwable t) {
            progressDoalog.dismiss();
            Toast.makeText(CommentPost.this, "Something went wrong...Please try later!", Toast.LENGTH_SHORT).show();
        }
    });
}
/*Method to generate List of data using RecyclerView with custom adapter*/
private void generateDataList(List<Comments> CommentsList) {
    recyclerView = findViewById(R.id.recyclerView);
    adapter = new CommentAdapter(this,CommentsList);
    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(CommentPost.this);
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setAdapter(adapter);
    //latest message
    recyclerView.scrollToPosition(adapter.getItemCount() - 1);
}

适配器：

@SuppressLint("RecyclerView")
@Override
public void onBindViewHolder(CommentAdapter.CustomViewHolder holder, int position) {
    holder.txtTitle.setText(dataList.get(position).getComment());
    holder.txttime.setText(dataList.get(position).getUpdated_at());
    holder.userNametitle.setText(dataList.get(position).getuser_name());

    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            //Toast.makeText(view.getContext(), "" + dataList.get(position).getId(), Toast.LENGTH_SHORT).show();
        }
    });

}

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

Answer 1

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Answer 2

第一件事函数生成的atatalist 必须仅首次致电
因此，我将从 onCreat 中调用它，

@Override
protected void onCreate(Bundle savedInstanceState){
     ...
     generateDataList();
}
private void generateDataList() {
    recyclerView = findViewById(R.id.recyclerView);
    adapter = new CommentAdapter(this,new ArrayList<>());
    RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(CommentPost.this);
    recyclerView.setLayoutManager(layoutManager);
    recyclerView.setAdapter(adapter);
}

您可以这样创建您的布局：

<androidx.core.widget.NestedScrollView 
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/nestedSV"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">
  
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
          
        <androidx.recyclerview.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:nestedScrollingEnabled="false"
            tools:listitem="@layout/user_rv_item" />
          
        <ProgressBar
            android:id="@+id/progressBar"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />
    </LinearLayout>
      
</androidx.core.widget.NestedScrollView>

我们将为 nestedscrollview 设置滚动侦听器

@Override
protected void onCreate(Bundle savedInstanceState){
    ...
    progressBar = findViewById(R.id.progressBar);
    nestedSV = findViewById(R.id.nestedSV);
    nestedSV.setOnScrollChangeListener(new NestedScrollView.OnScrollChangeListener() {
        @Override
        public void onScrollChange(NestedScrollView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
            // When the Scroll of NestedScrollView in bottom
            if (scrollY == v.getChildAt(0).getMeasuredHeight() - v.getMeasuredHeight()) {
                // show the progressbar and then get more data to the recyclerview
                progressBar.setVisibility(View.VISIBLE);
                showData();
            }
        }
    });
    generateDataList();
}

，然后我们将更改 showdata（）：

public void showData(){
    Call<List<Comments>> call = service.getComment(audioPath);
    call.enqueue(new Callback<List<Comments>>() {
        @Override
        public void onResponse(Call<List<Comments>> call, Response<List<Comments>> response) {
            // here instead of generateDataList we going to add the data with addToList
            addToList(response.body());
            progressBar.setVisibility(View.GONE);
        }
        @Override
        public void onFailure(Call<List<Comments>> call, Throwable t) {
            progressBar.setVisibility(View.GONE);
            Toast.makeText(CommentPost.this, "Something went wrong...Please try later!", Toast.LENGTH_SHORT).show();
        }
    });
}


private void addToList(List<Comments> commentsList) {
     // this is add commentsList data to the adapter list
     adapter. dataList.addAll(commentsList);
     adapter.notifyDataSetChanged();
}