给Recyclerview添加自定义分割线

用mRecyclerView.addItemDecoration()来加入分割线，谷歌没有提供默认的分割线需要我们继承RecyclerView.ItemDecoration来自定义分割线：

public class DividerItemDecoration extends RecyclerView.ItemDecoration {

private static final int[] ATTRS = new int[]{android.R.attr.listDivider};

public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;

public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;

private Drawable mDivider;

private int mOrientation;

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

public void setOrientation(int orientation){
    if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST){
        throw new IllegalArgumentException("invalid orientation");
    }
    mOrientation = orientation;
}

@Override
public void onDraw(Canvas c,RecyclerView parent){
    if (mOrientation == VERTICAL_LIST){
        drawVertical(c,parent);
    }else if (mOrientation == HORIZONTAL_LIST){
        drawHorizontal(c,parent);
    }
}

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

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

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

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

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

}

使用方式：

rlView.addItemDecoration(new DividerItemDecoration(this,DividerItemDecoration.VERTICAL_LIST));

style里加入：

<item name="android:listDivider">@drawable/line_drawable</item>

line_deawable.xml代码如下：

<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >

<solid android:color="@color/color_000000"/>
<size android:height="0.5dp"
    android:width="0.5dp"/>

</shape>