RecyclerView调用addItemDecoration添加自定义分割线

最近在做项目中使用RecyclerView的addItemDecoration方法添加分割线，出现了分割线在有些手机（比如魅蓝和小米手机）显示不出来的问题。

后来在网上找了一些资料，还是无法修改分割线颜色，最后找到了正确的方法，实现了修改分割线颜色和高度。

自定义RecyclerView.ItemDecoration类的子类SimpleDividerItemDecoration类，代码如下：

public class SimpleDividerItemDecoration extends RecyclerView.ItemDecoration {
    private Drawable mDivider;

    public SimpleDividerItemDecoration(Context context) {
        mDivider = context.getResources().getDrawable(R.drawable.line_divider);
    }

    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        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);

            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();

            int top = child.getBottom() + params.bottomMargin;
            int bottom = top + mDivider.getIntrinsicHeight();

            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }
}

说明：context.getResources().getDrawable(R.drawable.line_divider);

line_divider.xml:

说明：通过修改android:color和android:height可以修改分割线颜色和宽度。

最后，RecyclerView对象使用addItemDecoration方法添加分割线，代码如下：

recyclerView.addItemDecoration(new SimpleDividerItemDecoration(this));

原文地址：http://stackoverflow.com/questions/31242812/how-can-a-divider-line-be-added-in-an-android-recyclerview

上面方式定义的公共类SimpleDividerItemDecoration类可以被许多页面的RecyclerView共用，分割线的宽度和颜色统一，缺点是无法实现不同页面使用不同颜色和高度的分割线。

以下对SimpleDividerItemDecoration进行了修正，实现了自定义颜色和高度的分割线效果。

public class SimpleDividerItemDecoration extends RecyclerView.ItemDecoration {

    private Drawable mDivider;     //分割线Drawable
    private int mDividerHeight;  //分割线高度

    /**
     * 使用line_divider中定义好的颜色
     * @param context
     * @param dividerHeight 分割线高度
     */
    public SimpleDividerItemDecoration(Context context, int dividerHeight) {
        mDivider = ContextCompat.getDrawable(context, R.drawable.line_divider);
        mDividerHeight = dividerHeight;
    }

    /**
     *
     * @param context
     * @param divider 分割线Drawable
     * @param dividerHeight 分割线高度
     */
    public SimpleDividerItemDecoration(Context context, Drawable divider, int dividerHeight){
        if(divider == null){
            mDivider = ContextCompat.getDrawable(context, R.drawable.line_divider);
        }else{
            mDivider = divider;
        }
        mDividerHeight = dividerHeight;
    }

    //获取分割线尺寸
    @Override
    public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
        super.getItemOffsets(outRect, view, parent, state);
        outRect.set(0, 0, 0, mDividerHeight);
    }

    @Override
    public void onDrawOver(Canvas c, RecyclerView parent, RecyclerView.State state) {
        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);

            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();

            int top = child.getBottom() + params.bottomMargin;
            int bottom = top + mDividerHeight;
            mDivider.setBounds(left, top, right, bottom);
            mDivider.draw(c);
        }
    }

使用方法：

Drawable drawable = ContextCompat.getDrawable(getActivity(), R.drawable.line_divider_red);
recyclerView.addItemDecoration(new SimpleDividerItemDecoration(this,drawable, 5));