PinnedSectionItemDecoration

To ensure headers occupy the full width (span count) of the RecyclerView, your adapter must process the span count using FullSpanUtil. Override onAttachedToRecyclerView and onViewAttachedToWindow in your adapter to call FullSpanUtil.onAttachedToRecyclerView and FullSpanUtil.onViewAttachedToWindow respectively, passing the RecyclerView, the adapter instance, and the specific header type constant.

    @Override
    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
        super.onAttachedToRecyclerView(recyclerView);
        FullSpanUtil.onAttachedToRecyclerView(recyclerView, this, StockEntity.StockInfo.TYPE_HEADER);
    }

    @Override
    public void onViewAttachedToWindow(RecyclerView.ViewHolder holder) {
        super.onViewAttachedToWindow(holder);
        FullSpanUtil.onViewAttachedToWindow(holder, this, StockEntity.StockInfo.TYPE_HEADER);
    }

Large pinned headers are used when the header is a separate item in the adapter. Use PinnedHeaderItemDecoration.Builder to configure the decoration.

Key configuration options:

• new PinnedHeaderItemDecoration.Builder(headerType): Constructor requires the header type constant.
• .setDividerId(resId): Sets the drawable resource for the separator line.
• .enableDivider(true): Enables drawing the separator line (disabled by default).
• .setClickIds(resId): Specifies which child view IDs within the header should trigger click events.
• .disableHeaderClick(boolean): Enables or disables the header click event (defaults to false, meaning enabled).
• .setHeaderClickListener(OnHeaderClickAdapter): Sets the listener for header click events.

Note: The top layer of the header cannot have a marginTop set in its layout.

```java
      OnHeaderClickAdapter clickAdapter = new OnHeaderClickAdapter() {

          @Override
          public void onHeaderClick(View view, int id, int position) {
              switch (id) {
                  case R.id.fl:
                       // case OnItemTouchListener.HEADER_ID:
                       Toast.makeText(StockActivity.this, "click, tag: " + mAdapter.getData().get(position).pinnedHeaderName, Toast.LENGTH_SHORT).show();
                       break;
                   case R.id.iv_more:
                       Toast.makeText(StockActivity.this, "click " + mAdapter.getData().get(position).pinnedHeaderName + "'s more button", Toast.LENGTH_SHORT)
                             .show();
                       break;
                   case R.id.checkbox:
                       final CheckBox checkBox = (CheckBox) view;
                       checkBox.setChecked(!checkBox.isChecked());
                       // invalidate ItemDecorations to draw the header
                       mRecyclerView.invalidateItemDecorations();

                       mAdapter.getData().get(position).check = checkBox.isChecked();
                       mAdapter.notifyItemChanged(position + mHeaderItemDecoration.getDataPositionOffset());

                       break;
               }
           }

       };

    mRecyclerView.addItemDecoration(
             // Set the type of pinned header
             new PinnedHeaderItemDecoration.Builder(StockEntity.StockInfo.TYPE_HEADER)
             // Set separator line resources id.
             .setDividerId(R.drawable.divider)
             // Enable draw the separator line, by default it's disable.
             .enableDivider(true)
             // Set click event for the header and its internal child view.
             .setClickIds(R.id.iv_more)
             // Disable header click event， by default it's enable.
             .disableHeaderClick(false)
             // Set the listener. If the listener is not null but disable the header click event(eg. disableHeaderClick(true)), then the callback don't return.
             .setHeaderClickListener(clickAdapter)
             .create());
    ```

Small pinned headers are implemented by overlaying a small header view onto an existing item layout. To use this, your item layout (Layout B) should contain an additional view (e.g., an ImageView) that serves as the small header.

Implementation Steps:

1. Design your item layout to include the small header view (e.g., R.id.iv_small_pinned_header).
2. Use SmallPinnedHeaderItemDecoration.Builder to register the header view ID and the header item type.
3. Important: The small header view must not have a marginTop.

Key Builder Methods:

• SmallPinnedHeaderItemDecoration.Builder(int headerViewId, int headerType): Constructor specifying the ID of the small header view within the item and the item type.
• .enableDivider(boolean): Enables/disables dividers.
• .setDividerId(int resId): Sets the divider drawable.
• .setClickIds(int... ids): Specifies which sub-view IDs respond to clicks.
• .disableHeaderClick(boolean): Disables header click events.
• .setHeaderClickListener(OnHeaderClickAdapter listener): Sets the click listener.
• .create(): Finalizes the builder.

mRecyclerView.addItemDecoration(
    new SmallPinnedHeaderItemDecoration.Builder(R.id.iv_small_pinned_header, BaseHeaderAdapter.TYPE_HEADER)
    .enableDivider(true)
    .setDividerId(R.drawable.divider)
    .setClickIds(R.id.iv_small_pinned_header)
    .disableHeaderClick(true)
    .setHeaderClickListener(clickAdapter)
    .create());

Small pinned headers are used when the header is a child view embedded within a regular item layout (e.g., a small overlay).

To implement this:

1. Design your item layout (Layout B) to include the view that will act as the header (e.g., an ImageView with ID R.id.iv_small_pinned_header).
2. Use SmallPinnedHeaderItemDecoration.Builder to configure the decoration.

Key configuration options:

• new SmallPinnedHeaderItemDecoration.Builder(headerViewId, headerType): Constructor requires the ID of the view within the item that acts as the header and the header type constant.
• .enableDivider(true): Enables the separator line.
• .setDividerId(resId): Sets the divider drawable.
• .setClickIds(resId): Specifies the ID of the view within the item that should trigger click events.
• .disableHeaderClick(boolean): Enables or disables the header click event.
• .setHeaderClickListener(OnHeaderClickAdapter): Sets the listener for header click events.

Note: Like large headers, the top layer of the header cannot have marginTop set in its layout.

```java
     OnHeaderClickAdapter headerClickAdapter = new OnHeaderClickAdapter() {

          @Override
          public void onHeaderClick(View view, int id, int position) {
              if (id == R.id.iv_small_pinned_header) {
                  Toast.makeText(SecondActivity.this, "click tag: " + mAdapter.getData().get(position).getPinnedHeaderName(), Toast.LENGTH_SHORT).show();
              }
          }
     };
     mRecyclerView.addItemDecoration(
             // Constructor need to set the id and type of the header 
             new SmallPinnedHeaderItemDecoration.Builder(R.id.tv_small_pinned_header,BaseHeaderAdapter.TYPE_HEADER)
             // Enable draw the separator line, by default it's disable.
             .enableDivider(true)
             // Set separator line resources id.
             .setDividerId(R.drawable.divider)
             // Set click event for the header and its internal child view.
             .setClickIds(R.id.tv_small_pinned_header)
             // Disable header click event， by default it's enable.
             .disableHeaderClick(false)
             // Set the listener. If the listener is not null but disable the header click event(eg. disableHeaderClick(true)), then the callback don't return.
             .setHeaderClickListener(clickAdapter)
             .create());
    ```

Big pinned headers (headers that act as distinct sections) are implemented using PinnedHeaderItemDecoration.Builder. This requires a builder pattern to configure parameters like the header type, divider settings, and click listeners.

Important: The outermost layout containing the header must not have a marginTop, otherwise, the header may not properly cover the content when scrolling up.

Key Builder Methods:

• PinnedHeaderItemDecoration.Builder(int headerType): Constructor specifying the item type that represents a header.
• .setDividerId(int resId): Sets the drawable resource for the divider.
• .enableDivider(boolean): Enables or disables divider drawing (default is false).
• .setClickIds(int... ids): Specifies the IDs of the header or its sub-views that should trigger click events.
• .disableHeaderClick(boolean): Disables click events for the header (default is false).
• .setHeaderClickListener(OnHeaderClickAdapter listener): Sets the listener for click, double-click, and long-press events.
• .create(): Finalizes the builder.

mRecyclerView.addItemDecoration(
    new PinnedHeaderItemDecoration.Builder(StockEntity.StockInfo.TYPE_HEADER)
    .setDividerId(R.drawable.divider)
    .enableDivider(true)
    .setClickIds(R.id.iv_more)
    .disableHeaderClick(false)
    .setHeaderClickListener(clickAdapter)
    .create());