接觸過Android開發的同學們都知道在Android中訪問程序資源基本都是通過資源ID來訪問。這樣開發起來很簡單，并且可以不去考慮各種分辨率，語言等不同資源顯式指定。
但是，有時候也會有一些問題，比如我們根據服務器端的值取圖片，但是服務器端絕對不會返回給我們的是資源id，最多是一種和文件名相關聯的值，操作資源少的時候，可以維護一個容器進行值與資源ID的映射，但是多的話，就需要另想辦法了。
Resources res = getResources();
final String packageName = getPackageName();
int imageResId = res.getIdentifier("ic_launcher", "drawable", packageName);
int imageResIdByAnotherForm = res.getIdentifier(packageName + ":drawable/ic_launcher", null, null);
int musicResId = res.getIdentifier("test", "raw", packageName);
int notFoundResId = res.getIdentifier("activity_main", "drawable", packageName);
Log.i(LOGTAG, "testGetResourceIds imageResId = " + imageResId
+ ";imageResIdByAnotherForm = " + imageResIdByAnotherForm
+ ";musicResId=" + musicResId
+ ";notFoundResId =" + notFoundResId);
**
* Return a resource identifier for the given resource name. A fully
* qualified resource name is of the form "package:type/entry". The first
* two components (package and type) are optional if defType and
* defPackage, respectively, are specified here.
*
* <p>Note: use of this function is discouraged. It is much more
* efficient to retrieve resources by identifier than by name.
*
* @param name The name of the desired resource.
* @param defType Optional default resource type to find, if "type/" is
* not included in the name. Can be null to require an
* explicit type.
* @param defPackage Optional default package to find, if "package:" is
* not included in the name. Can be null to require an
* explicit package.
*
* @return int The associated resource identifier. Returns 0 if no such
* resource was found. (0 is not a valid resource ID.)
*/
public int getIdentifier(String name, String defType, String defPackage) {
try {
return Integer.parseInt(name);
} catch (Exception e) {
// Ignore
}
return mAssets.getResourceIdentifier(name, defType, defPackage);
}
