最近在做專案中使用RecyclerView的addItemDecoration方法新增分割線，出現了分割線在有些手機（比如魅藍和小米手機）顯示不出來的問題。

後來在網上找了一些資料，還是無法修改分割線顏色，最後找到了正確的方法，實現了修改分割線顏色和高度。

自定義RecyclerView.ItemDecoration類的子類SimpleDividerItemDecoration類，程式碼如下：

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);
        }
    }
}
 

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

line_divider.xml:

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <size
        android:width="1dp"
        android:height="1dp" />
    <solid android:color="@color/dark_gray" />

</shape>
 

說明：通過修改android:color和android:height可以修改分割線顏色和寬度。

recyclerView.addItemDecoration(new SimpleDividerItemDecoration(this));

上面方式定義的公共類SimpleDividerItemDecoration類可以被許多頁面的RecyclerView共用，分割線的寬度和顏色統一，缺點是無法實現不同頁面使用不同顏色和高度的分割線。

以下對SimpleDividerItemDecoration進行了修正，實現了自定義顏色和高度的分割線效果。

public class SimpleDividerItemDecoration extends RecyclerView.ItemDecoration {

    private Drawable mDivider;     //分割線Drawable
    private int mDividerHeight;  //分割線高度

    /**
     * 使用line_divider中定義好的顏色
     * @param context
     * @param dividerHeight 分割線高度
     */
    public SimpleDividerItemDecoration(Context context, int dividerHeight) {
        mDivider = ContextCompat.getDrawable(context, R.drawable.line_divider);
        mDividerHeight = dividerHeight;
    }

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

    //獲取分割線尺寸
    @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);
        }
    }

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