android Class.forName jette l'exception

Question

Je joue avec la réflexion Java dans un projet Android.

code source:

Log.d("LOG", "begin"); 
try { 
    final android.view.View.OnSystemUiVisibilityChangeListener unusedVar = new android.view.View.OnSystemUiVisibilityChangeListener() { 

     @Override 
     public void onSystemUiVisibilityChange(int visibility) { 
      // TODO Auto-generated method stub 

     } 
    }; 
    Log.d("LOG", "unusedVar is null = " + (unusedVar == null? "Yes": "No")); 
    Class newClass = Class.forName("android.view.View.OnSystemUiVisibilityChangeListener"); 
    Log.d("LOG", "newClass created"); 
} catch (Exception ex) { 
    Log.d("LOG", "Failed to create newClass", ex); 
} 
Log.d("LOG", "end"); 

• Le code ci-dessus est en onCreate() de mon activité.
• La cible de génération du projet est Android 4.0.
• Je l'utilise sur un appareil avec Android 4.0.4.

Résultat: La unusedVar variable n'est pas null, mais Class.forName jette un ClassNotFoundException.

Log:

D/LOG(13205): begin 
D/LOG(13205): unusedVar is null = No 
D/LOG(13205): Failed to create newClass 
D/LOG(13205): java.lang.ClassNotFoundException: android.view.View.OnSystemUiVisibilityChangeListener 
D/LOG(13205): at java.lang.Class.classForName(Native Method) 
D/LOG(13205): at java.lang.Class.forName(Class.java:217) 
D/LOG(13205): at java.lang.Class.forName(Class.java:172) 
D/LOG(13205): at com.MyActivity.onCreate(VideoPlayerActivity.java:100) 
D/LOG(13205): at android.app.Activity.performCreate(Activity.java:4465) 
D/LOG(13205): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049) 
D/LOG(13205): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920) 
D/LOG(13205): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981) 
D/LOG(13205): at android.app.ActivityThread.access$600(ActivityThread.java:123) 
D/LOG(13205): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147) 
D/LOG(13205): at android.os.Handler.dispatchMessage(Handler.java:99) 
D/LOG(13205): at android.os.Looper.loop(Looper.java:137) 
D/LOG(13205): at android.app.ActivityThread.main(ActivityThread.java:4424) 
D/LOG(13205): at java.lang.reflect.Method.invokeNative(Native Method) 
D/LOG(13205): at java.lang.reflect.Method.invoke(Method.java:511) 
D/LOG(13205): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784) 
D/LOG(13205): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551) 
D/LOG(13205): at dalvik.system.NativeStart.main(Native Method) 
D/LOG(13205): Caused by: java.lang.NoClassDefFoundError: android/view/View/OnSystemUiVisibilityChangeListener 
D/LOG(13205): ... 18 more 
D/LOG(13205): Caused by: java.lang.ClassNotFoundException: android.view.View.OnSystemUiVisibilityChangeListener 
D/LOG(13205): at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:61) 
D/LOG(13205): at java.lang.ClassLoader.loadClass(ClassLoader.java:501) 
D/LOG(13205): at java.lang.ClassLoader.loadClass(ClassLoader.java:461) 
D/LOG(13205): ... 18 more 
D/LOG(13205): end 

Pourquoi? Est-ce parce que android.view.View.OnSystemUiVisibilityChangeListener est une interface plutôt qu'une classe?

Answer 1

L'interface OnSystemUiVisibilityChangeListener est imbriquée dans la classe View, donc je crois que vous devriez faire Class.forName("android.view.View$OnSystemUiVisibilityChangeListener"); (notez le '$').

Références:

• http://developer.android.com/reference/android/view/View.html
• http://developer.android.com/reference/android/view/View.OnSystemUiVisibilityChangeListener.html