谷歌推荐我们，在开发安卓系统应用程序的时候，要把资源从代码中分离出来，这样便于我们单独维护它们。采取分离的资源设计，我们还可以提供可选资源，支持特定的设备配置譬如不同的语言或屏幕尺寸，随着越来越多的Android设备可选用不同的配置，这变得越来越重要。为了提供不同配置的兼容性，你必须在你的项目的res/目录中组织资源。按类型和配置，使用不同的子目录。
对于任何类型的资源，你可以为你的应用程序提供一个默认和多个可选资源：
- 默认资源就是不管你什么配置我都强制使用或者没有满足配置的可选资源时使用的资源。
- 可选资源是提供给特定配置使用的资源。我们给res的自文件夹名提供一个配置限定符，从而把特定配置和特定可选资源关联起来。（【注】所以，这是一种高度分立的资源配置，我们不是在代码中通过if...else等条件语句来判断使用哪个可选资源，而是由系统的某个服务自动判断当前配置和资源文件夹名来加载合适的资源）
1、资源类型：
| Directory | Resource Type |
|---|---|
animator/ |
XML files that define property animations. |
anim/ |
XML files that define tween animations. (Property animations can also be saved in this directory, but the animator/ directory is preferred for property animations to distinguish between the two types.) |
color/ |
XML files that define a state list of colors. See Color State List Resource |
drawable/ |
Bitmap files ( .png, .9.png, .jpg, .gif) or XML files that are compiled into the following drawable resource subtypes:
See Drawable Resources. |
mipmap/ |
Drawable files for different launcher icon densities. For more information on managing launcher icons with mipmap/ folders, see Managing Projects Overview. |
layout/ |
XML files that define a user interface layout. See Layout Resource. |
menu/ |
XML files that define application menus, such as an Options Menu, Context Menu, or Sub Menu. See Menu Resource. |
raw/ |
Arbitrary files to save in their raw form. To open these resources with a raw InputStream, call Resources.openRawResource() with the resource ID, which is R.raw.filename.
However, if you need access to original file names and file hierarchy, you might consider saving some resources in the |
values/ |
XML files that contain simple values, such as strings, integers, and colors. Whereas XML resource files in other Because each resource is defined with its own XML element, you can name the file whatever you want and place different resource types in one file. However, for clarity, you might want to place unique resource types in different files. For example, here are some filename conventions for resources you can create in this directory:
See String Resources, Style Resource, and More Resource Types. |
xml/ |
Arbitrary XML files that can be read at runtime by calling Resources.getXML(). Various XML configuration files must be saved here, such as a searchable configuration. |