Android中实现根据资源名获取资源ID

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);

I/MainActivity( 4537): testGetResourceIds imageResId = 2130837504;imageResIdByAnotherForm = 2130837504;musicResId=2130968576;notFoundResId =0

**
     * 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.
     *
     *

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);
    }

/**
     * Retrieve the resource identifier for the given resource name.
     */
    /*package*/ native final int getResourceIdentifier(String type,
                                                       String name,
                                                       String defPackage);