imageview的内容不会传递给mainactivity的imageview

Question

我想将图像从一个活动转移到另一个活动。我尝试将图像转换为发送方活动（PhotoActivity）中的字节数组，并在点击按钮'btdn'时解码数组以在接收方（MainActivity）上形成原始位图图像，但这不起作用。图像在发件人活动的图像视图中可见，但在单击按钮时会停止。这是我的代码： -

PhotoActivity.java

data Stack a = Stack [a]
               deriving (Eq,Show,Ord)

printelems :: (Show a) => [a] -> String
printelems [] = ""
printelems x = show x
printelems (x:xs) = show x ++ "->" ++ (printelems xs)



instance (Show a) => Show (Stack a)
 where
 show (Stack l) = printelems l

empty :: Stack a
empty = []

push :: a -> Stack a -> Stack a
push x s = x:s

MainActivity.java

 [-sum(g[j]*w[i-j]*dz for j in range(i)) for i in range(len(g))]