RuntimeError: You must compile your model before using it.

RuntimeError: You must compile your model before using it.
出现这个问题是因为程序检测到你模型还未编译，解决方法就是在你搭建model的起始行，手动指定 input_shape 参数的维度。

models.add(Conv2D(6, (5, 5), activation='relu', input_shape=(28, 28, 1)))
models.add(AveragePooling2D(pool_size=(2, 2), strides=2))
models.add(Conv2D(16, (5, 5), activation='relu'))
models.add(AveragePooling2D(pool_size=(2, 2), strides=2))
models.add(Flatten())
models.add(Dense(120, activation='relu'))
models.add(Dense(84, activation='relu'))
models.add(Dense(num_class, activation='softmax'))