RecyclerView滑動監聽與加載更多

在Android中，為RecyclerView實現滑動監聽和加載更多功能，可以通過以下步驟來完成：

1. 創建一個自定義的RecyclerView類：這個類將用于監聽滑動事件并觸發加載更多的操作。

public class CustomRecyclerView extends RecyclerView {
    private OnLoadMoreListener onLoadMoreListener;
    private boolean isLoading = false;

    public CustomRecyclerView(Context context) {
        super(context);
    }

    public CustomRecyclerView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public CustomRecyclerView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    public void setOnLoadMoreListener(OnLoadMoreListener listener) {
        this.onLoadMoreListener = listener;
    }

    public void setLoading(boolean loading) {
        isLoading = loading;
    }

    @Override
    protected void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
        super.onScrolled(recyclerView, dx, dy);
        int visibleItemCount = recyclerView.getChildCount();
        int totalItemCount = recyclerView.getAdapter().getItemCount();
        int firstVisibleItemPosition = ((LinearLayoutManager) recyclerView.getLayoutManager()).findFirstVisibleItemPosition();

        if (!isLoading && !recyclerView.canScrollVertically()) {
            if ((visibleItemCount + firstVisibleItemPosition) >= totalItemCount && firstVisibleItemPosition >= 0) {
                onLoadMoreListener.onLoadMore();
            }
        }
    }

    public interface OnLoadMoreListener {
        void onLoadMore();
    }
}

2. 在你的Activity或Fragment中使用這個自定義的RecyclerView：

public class MainActivity extends AppCompatActivity {
    private CustomRecyclerView customRecyclerView;
    private MyAdapter adapter;
    private List<MyData> dataList = new ArrayList<>();

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

        customRecyclerView = findViewById(R.id.custom_recycler_view);
        customRecyclerView.setLayoutManager(new LinearLayoutManager(this));
        adapter = new MyAdapter(dataList);
        customRecyclerView.setAdapter(adapter);

        customRecyclerView.setOnLoadMoreListener(new CustomRecyclerView.OnLoadMoreListener() {
            @Override
            public void onLoadMore() {
                loadMoreData();
            }
        });

        // 初始加載數據
        loadInitialData();
    }

    private void loadInitialData() {
        // 模擬網絡請求加載數據
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i < 20; i++) {
                    dataList.add(new MyData("Item " + (dataList.size() + 1)));
                }
                adapter.notifyDataSetChanged();
            }
        }, 1000);
    }

    private void loadMoreData() {
        customRecyclerView.setLoading(true);
        // 模擬網絡請求加載更多數據
        new Handler().postDelayed(new Runnable() {
            @Override
            public void run() {
                for (int i = 0; i < 20; i++) {
                    dataList.add(new MyData("Item " + (dataList.size() + 1)));
                }
                adapter.notifyDataSetChanged();
                customRecyclerView.setLoading(false);
            }
        }, 1000);
    }
}

3. 創建一個RecyclerView.Adapter來管理數據：

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {
    private List<MyData> dataList;

    public MyAdapter(List<MyData> dataList) {
        this.dataList = dataList;
    }

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

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
        holder.textView.setText(dataList.get(position).getText());
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {
        public TextView textView;

        public ViewHolder(View itemView) {
            super(itemView);
            textView = itemView.findViewById(R.id.text_view);
        }
    }
}

4. 在布局文件中添加CustomRecyclerView：

<com.example.myapplication.CustomRecyclerView
    android:id="@+id/custom_recycler_view"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

這樣，當用戶滾動到RecyclerView的底部時，就會觸發加載更多的操作。