理解 android values/dimens
Understanding android values/dimens
所以我在 values/dimens & values/dimens-mdpi
<dimen name="rv_height">220dp</dimen>
<dimen name="rv_width">280dp</dimen>
以及 values-xxhdpi/dimens
中的以下内容
<dimen name="rv_height">260dp</dimen>
<dimen name="rv_width">320dp</dimen>
我的问题是，当我在 480 x 800 hdpi API 17 模拟器上 运行 这个时，为什么它从 xxhdpi 文件夹而不是常规的 dimen 或 dimens-mdpi 文件夹？
To simplify the way that you design your user interfaces for multiple
screens, Android divides the range of actual screen sizes and
densities into:
ldpi (low) ~120dpi
mdpi (medium) ~160dpi
hdpi (high) ~240dpi
xhdpi (extra-high) ~320dpi
xxhdpi (extra-extra-high) ~480dpi
xxxhdpi (extra-extra-extra-high) ~640dpi
编辑：
我会尽力向您解释：
hdpi 上 480 像素的设备具有 320 dp，因为来自文档，"on a 240 dpi screen, 1 dp equals 1.5 physical pixels"。表示 400 px /1.5 = 320 dp.
现在，你有 values/dimens & values/dimens-mdpi && values-xxhdpi/dimens
再次根据文档
However, when the system is looking for a density-specific resource
and does not find it in the density-specific directory, it won't
always use the default resources. The system may instead use one of
the other density-specific resources in order to provide better
results when scaling. For example, when looking for a low-density
resource and it is not available, the system prefers to scale-down the
high-density version of the resource, because the system can easily
scale a high-density resource down to low-density by a factor of 0.5,
with fewer artifacts, compared to scaling a medium-density resource by
a factor of 0.75.
结论：不保证在缺少 res 目录的情况下始终使用默认目录。在您的情况下，它已将高密度资源缩小到低密度。
我希望现在清楚了。
所以我在 values/dimens & values/dimens-mdpi
<dimen name="rv_height">220dp</dimen>
<dimen name="rv_width">280dp</dimen>
以及 values-xxhdpi/dimens
中的以下内容<dimen name="rv_height">260dp</dimen>
<dimen name="rv_width">320dp</dimen>
我的问题是，当我在 480 x 800 hdpi API 17 模拟器上 运行 这个时，为什么它从 xxhdpi 文件夹而不是常规的 dimen 或 dimens-mdpi 文件夹？
To simplify the way that you design your user interfaces for multiple screens, Android divides the range of actual screen sizes and densities into:
ldpi (low) ~120dpi
mdpi (medium) ~160dpi
hdpi (high) ~240dpi
xhdpi (extra-high) ~320dpi
xxhdpi (extra-extra-high) ~480dpi
xxxhdpi (extra-extra-extra-high) ~640dpi
编辑：
我会尽力向您解释：
hdpi 上 480 像素的设备具有 320 dp，因为来自文档，"on a 240 dpi screen, 1 dp equals 1.5 physical pixels"。表示 400 px /1.5 = 320 dp.
现在，你有 values/dimens & values/dimens-mdpi && values-xxhdpi/dimens
再次根据文档
However, when the system is looking for a density-specific resource and does not find it in the density-specific directory, it won't always use the default resources. The system may instead use one of the other density-specific resources in order to provide better results when scaling. For example, when looking for a low-density resource and it is not available, the system prefers to scale-down the high-density version of the resource, because the system can easily scale a high-density resource down to low-density by a factor of 0.5, with fewer artifacts, compared to scaling a medium-density resource by a factor of 0.75.
结论：不保证在缺少 res 目录的情况下始终使用默认目录。在您的情况下，它已将高密度资源缩小到低密度。
我希望现在清楚了。