Android可以支持小于1dp的dp吗? [英] Can Android support dp's less than 1dp?
问题描述
我正在制作日历，我需要一个网格.问题是边界，或者说是每个网格之间的空间(1 dp)是我用来模拟网格的方式.但是它比较厚.我正在查看具有边框的其他日历应用程序，它们非常薄.即使我使用drawable形状并将其设置为1dp，它仍然具有该厚度.我尝试使用.5，但这似乎不起作用.那不可能吗?
I am making a calendar and I need a grid. Problem is the borders, or rather the space between each grid, which is what I am using to kind of simulate a grid, is 1 dp. But its rather thick. I am looking at other calendar apps that have the borders, and they are very thin. Even if I were to use a drawable shape and make it 1dp, it still has that thickness. I tried using .5, but that did not seem to work. Is that not possible?
推荐答案
Android确实允许您将dp的分数值输入XML，尽管我不确定我会推荐这样做，因为结果变得难以预测/计算.设备使用以下公式(基本上)将dp值转换为像素:
Android does allow you to enter fractional values for dp into XML, though I'm not sure I would recommend it because the results become less easy to predict/compute. Devices convert dp values into pixels using (basically) the following formula:
px = (int)(scale * dp + 0.5)
(即设备密度标度四舍五入到最接近的整个像素值)
(i.e. the device density scale rounded to the nearest whole pixel value)
scale值将基于设备的屏幕密度:
The scale value would be based on the screen density of the device:
- MDPI = 1
- HDPI = 1.5
- XHDPI = 2
- XXHDPI = 3
因此，0.5dp将导致上述密度的{1px，1px，1px，2px}，而1dp将是{1px，2px，2px，3px}.像0.1dp这样的微小值将解析为{1px，1px，1px，1px}，因为除非公式中小于c7的值，否则上述公式中小于1的任何内容都会解析为单个像素(无法绘制比单个像素宽度).
So 0.5dp would result in {1px, 1px, 1px, 2px} for the above densities, whereas 1dp would be {1px, 2px, 2px, 3px}. A tiny value like 0.1dp would resolve to {1px, 1px, 1px, 1px} because anything less than 1 in the above formula resolves to a single pixel unless the value was explicitly 0dp (it's not possible to draw something thinner than a single pixel width).
如果要确保使用尽可能薄的宽度，最好使用px而不是像dp这样的缩放单位明确定义宽度.设置1px的值将在所有设备上绘制一个像素，并且比希望0.5dp或0.1dp做相同的操作更具可读性.
If you want to ensure that thinnest possible width is used, probably best to define the width explicitly with px instead of a scaled unit like dp. Setting a value of 1px will draw with a single pixel on all devices, and is much more readable than hoping 0.5dp or 0.1dp does the same.
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