è possibile eseguire la scansione del classpath android per le annotazioni?

Question

Desidero eseguire la scansione del classpath per alcune annotazioni in Android.

ho trovato solo una soluzione a questo problema: http://mindtherobot.com/blog/737/android-hacks-scan-android-classpath/

E come scrive l'autore questa soluzione funziona, ma ha diverse limitazioni. Ci sono dei modi a prova di futuro per fare questo in Android? Qualsiasi libreria che fornisce questa funzionalità?

Answer 1

Questo funziona per me usando Android 3,0

public static <T extends Annotation> List<Class> getClassesAnnotatedWith(Class<T> theAnnotation){ 

    // In theory, the class loader is not required to be a PathClassLoader 
    PathClassLoader classLoader = (PathClassLoader) Thread.currentThread().getContextClassLoader(); 
    Field field = null; 
    ArrayList<Class> candidates = new ArrayList<Class>(); 

    try { 
     field = PathClassLoader.class.getDeclaredField("mDexs"); 
     field.setAccessible(true); 
    } catch (Exception e) { 
     // nobody promised that this field will always be there 
     Log.e(TAG, "Failed to get mDexs field", e); 
    } 

    DexFile[] dexFile = null; 
    try { 
     dexFile = (DexFile[]) field.get(classLoader); 
    } catch (Exception e) { 
     Log.e(TAG, "Failed to get DexFile", e); 
    } 

    for (DexFile dex : dexFile) { 
     Enumeration<String> entries = dex.entries(); 
     while (entries.hasMoreElements()) { 
     // Each entry is a class name, like "foo.bar.MyClass" 
     String entry = entries.nextElement(); 

     // Load the class 
     Class<?> entryClass = dex.loadClass(entry, classLoader); 
     if (entryClass != null && entryClass.getAnnotation(theAnnotation) != null) { 
      Log.d(TAG, "Found: " + entryClass.getName()); 
      candidates.add(entryClass); 
     } 
     } 
    } 

    return candidates; 
}  

Ho anche creato uno al determin se una classe è stata derivata da X

public static List<Class> getClassesSuperclassedOf(Class theClass){ 

    // In theory, the class loader is not required to be a PathClassLoader 
    PathClassLoader classLoader = (PathClassLoader) Thread.currentThread().getContextClassLoader(); 
    Field field = null; 
    ArrayList<Class> candidates = new ArrayList<Class>(); 

    try { 
     field = PathClassLoader.class.getDeclaredField("mDexs"); 
     field.setAccessible(true); 
    } catch (Exception e) { 
     // nobody promised that this field will always be there 
     Log.e(TAG, "Failed to get mDexs field", e); 
    } 

    DexFile[] dexFile = null; 
    try { 
     dexFile = (DexFile[]) field.get(classLoader); 
    } catch (Exception e) { 
     Log.e(TAG, "Failed to get DexFile", e); 
    } 

    for (DexFile dex : dexFile) { 
     Enumeration<String> entries = dex.entries(); 
     while (entries.hasMoreElements()) { 
     // Each entry is a class name, like "foo.bar.MyClass" 
     String entry = entries.nextElement(); 

     // Load the class 
     Class<?> entryClass = dex.loadClass(entry, classLoader); 
     if (entryClass != null && entryClass.getSuperclass() == theClass) { 
      Log.d(TAG, "Found: " + entryClass.getName()); 
      candidates.add(entryClass); 
     } 
     } 
    } 

    return candidates; 
} 

godere - B