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[操作系统]RecyclerView如何消除底部的分割线


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。
 
大功告成!!!