在谷歌I / O 2012 Android应用程序的动作条的标志来代替正常的应用程序图标。在开源项目中，我能找到的是340x72和present只有在这个层面的形象。我搜索如果在动作条使用商标某些指定大小，但我没有发现任何东西。你对此有所了解？

In the Google I/O 2012 Android App an actionbar logo is used instead of the normal app icon. In the open source project I could find the image which is 340x72 and present only in this dimension. I searched if there is some specified size for using a logo in the actionbar, but I did not find anything. Do you know something about this?

推荐答案

我看着YouTube应用程序的资源，因为这似乎是唯一的官方谷歌的应用程序（除了I / O），它使用了操作栏徽标的时刻。

I looked into the resources of the YouTube app, since that seems to be the only official Google app (besides I/O) that uses an action bar logo at the moment.

它包含三个可绘制的标志：

It contains three drawables for the logo:

drawable- MDPI /ic_logo_wide.png（75× 32 PX） drawable- 华电国际 /ic_logo_wide.png（112 x 48 PX） drawable- xhdpi /ic_logo_wide.png（149× 64 PX） drawable-mdpi/ic_logo_wide.png (75 x 32 px) drawable-hdpi/ic_logo_wide.png (112 x 48 px) drawable-xhdpi/ic_logo_wide.png (149 x 64 px)

据从Android的设计指南影像学，这些图像的高度匹配规范的操作栏的图标，这是 32×32 DP 。

According to Iconography from the Android design guidelines, those images' heights match the specification for the action bar icons, which is 32 x 32 dp.

32 DP = 32 PX（MDPI） 在32个DP * 1.5 = 48 PX（华电国际） 在32个DP * 2 = 64 PX（XHDPI） 32 dp = 32 px (MDPI) 32 dp * 1.5 = 48 px (HDPI) 32 dp * 2 = 64 px (XHDPI)

您会发现，在 72 从I / O的应用程序PX（XHDPI）显示不出来。我想，他们只是想增加标志的高度位。

You'll notice that the 72 px (XHDPI) from the I/O app don't show up. I guess, they just wanted to increase the logo's height a bit.

如果一个绘制在XHDPI只提供Android的扩展下来，这比提供的图片，在适当的尺寸少高性能。我想，这只是接受了I / O应用程序的开发者。

If a drawable is only provided in XHDPI, Android scales it down, which is a little less performant than providing the images in the proper sizes. I guess, this was just accepted by the developers of the I/O app.