RecyclerView消除底部分割线的方法

最近遇到一个问题，用RecyclerView显示数据，纵向列表显示，添加默认分割线。

问题是：底部也会显示分割线，这很影响美观。

怎么解决这个问题呢？我想了很多办法，毫无头绪。。。

最后，查看默认分割线的类DividerItemDecoration的源码：

public class DividerItemDecoration extends ItemDecoration {
private static final int[] ATTRS = new int[]{16843284};
public static final int HORIZONTAL_LIST = 0;
public static final int VERTICAL_LIST = 1;
private Drawable mDivider;
private int mOrientation;

public DividerItemDecoration(Context context, int orientation) {
 TypedArray a = context.obtainStyledAttributes(ATTRS);
 this.mDivider = a.getDrawable(0);
 a.recycle();
 this.setOrientation(orientation);
}

public void setOrientation(int orientation) {
 if(orientation != 0 && orientation != 1) {
  throw new IllegalArgumentException("invalid orientation");
 } else {
  this.mOrientation = orientation;
 }
}

public void onDraw(Canvas c, RecyclerView parent) {
 if(this.mOrientation == 1) {
  this.drawVertical(c, parent);
 } else {
  this.drawHorizontal(c, parent);
 }

}

public void drawVertical(Canvas c, RecyclerView parent) {
 int left = parent.getPaddingLeft();
 int right = parent.getWidth() - parent.getPaddingRight();
 int childCount = parent.getChildCount();

for(int i = 0; i < childCount; ++i) {
  View child = parent.getChildAt(i);
  LayoutParams params = (LayoutParams)child.getLayoutParams();
  int top = child.getBottom() + params.bottomMargin;
  int bottom = top + this.mDivider.getIntrinsicHeight();
  this.mDivider.setBounds(left, top, right, bottom);
  this.mDivider.draw(c);
 }

}

public void drawHorizontal(Canvas c, RecyclerView parent) {
 int top = parent.getPaddingTop();
 int bottom = parent.getHeight() - parent.getPaddingBottom();
 int childCount = parent.getChildCount();

for(int i = 0; i < childCount; ++i) {
  View child = parent.getChildAt(i);
  LayoutParams params = (LayoutParams)child.getLayoutParams();
  int left = child.getRight() + params.rightMargin;
  int right = left + this.mDivider.getIntrinsicHeight();
  this.mDivider.setBounds(left, top, right, bottom);
  this.mDivider.draw(c);
 }

}

public void getItemOffsets(Rect outRect, int itemPosition, RecyclerView parent) {
 if(this.mOrientation == 1) {
  outRect.set(0, 0, 0, this.mDivider.getIntrinsicHeight());
 } else {
  outRect.set(0, 0, this.mDivider.getIntrinsicWidth(), 0);
 }

}
}

因为我用到的是垂直列表，用到的是红色字体处的代码：

public void drawVertical(Canvas c, RecyclerView parent) {
 int left = parent.getPaddingLeft();
 int right = parent.getWidth() - parent.getPaddingRight();
 int childCount = parent.getChildCount();

for(int i = 0; i < childCount; ++i) {
  View child = parent.getChildAt(i);
  LayoutParams params = (LayoutParams)child.getLayoutParams();
  int top = child.getBottom() + params.bottomMargin;
  int bottom = top + this.mDivider.getIntrinsicHeight();
  this.mDivider.setBounds(left, top, right, bottom);
  this.mDivider.draw(c);
 }

}

从代码中很容易看出只要修改for循环中的内容就可去掉底部的分割线：

public void drawVertical(Canvas c, RecyclerView parent) {
 int left = parent.getPaddingLeft();
 int right = parent.getWidth() - parent.getPaddingRight();
 int childCount = parent.getChildCount();

for(int i = 0; i < childCount-1; ++i) {
  View child = parent.getChildAt(i);
  LayoutParams params = (LayoutParams)child.getLayoutParams();
  int top = child.getBottom() + params.bottomMargin;
  int bottom = top + this.mDivider.getIntrinsicHeight();
  this.mDivider.setBounds(left, top, right, bottom);
  this.mDivider.draw(c);
 }

}

因为这个类我们不能直接修改，所以我们可以自定义一个类，修改相应内容，添加分割线的时候，使用自定义类。