java - 在 RecyclerView 项目之间设置自定义分隔线

Question

我正在尝试在 Recyclerview 项目之间设置一条自定义分隔虚线，如下所示:

XML:

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

    <stroke
        android:width="1dp"
        android:color="#000"
        android:dashWidth="20px"
        android:dashGap="50px" />
</shape>

Java:

DividerItemDecoration itemDecorator = new DividerItemDecoration(getContext(), DividerItemDecoration.VERTICAL);
itemDecorator.setDrawable(ContextCompat.getDrawable(getContext(), R.drawable.dashedline));

上面的代码不能代替虚线我得到这个:

Answer 1

DividerItemDecoration 假定您提供的可绘制对象是实心矩形，并且恼人​​地忽略了您的行 XML 定义。我发现的解决方法是手动创建平铺 BitmapDrawable，例如:

    // get pixel count for 1 dip
    float dip1 = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 1f, getContext().getResources().getDisplayMetrics());

    // create a bitmap to draw our dash
    Bitmap bitmap = Bitmap.createBitmap((int)(15f * dip1) , (int)dip1, Bitmap.Config.ARGB_8888);
    Canvas canvas = new Canvas(bitmap);
    Paint paint = new Paint();

    // fill the bitmap with the background colour of the list items
    canvas.drawColor(listItemBackgroundColour);

    // create a dash effect dash with = 10 dip, dash gap = 5 dip
    paint.setPathEffect(new DashPathEffect(new float [] { 10f * dip1, 5f * dip1 }, 0));

    // draw a single pixel wide line across the bitmap
    paint.setStrokeWidth(dip1);
    paint.setColor(lineColour);
    paint.setStyle(Paint.Style.STROKE);
    canvas.drawLine(0f, dip1 / 2f, 15f * dip1, dip1 / 2f, paint);

    // now create a tiled drawable using the bitmap
    BitmapDrawable drawable = new BitmapDrawable(context.getResources(), bitmap);
    drawable.setTileModeX(Shader.TileMode.REPEAT);

    // pass the drawable to the item decorator
    DividerItemDecoration itemDecorator = new DividerItemDecoration(getContext(), layoutManager.getOrientation());
    itemDecorator.setDrawable(drawable);
    addItemDecoration(itemDecorator);

虽然不像 XML 形状资源定义那样整洁，但它可以解决问题。

请注意，您需要知道回收站项目背景的颜色才能混合到虚线中，否则您将通过虚线的间隙显示主题背景颜色。

希望这对您有所帮助。