Android判断包名和类名是否存在的方法

1.对包名的判断,异常则说明不存在:

try {
PackageManager pm = getPackageManager();
pm.getPackageInfo("com.org", PackageManager.GET_ACTIVITIES);
} catch (NameNotFoundException e) {
     // TODO Auto-generated catch block
     e.printStackTrace();
}

2.对类名的判断,异常则说明不存在:

try {
     Class.forName("com.org.MainActivity");
     } catch (ClassNotFoundException e) {
     // TODO Auto-generated catch block    
return;
     }