错误：包 R 不存在。 我必须添加这些包吗？

Question

I have added some java functions from Project A into Project B. Then, when I try to run Project B, I received the error. When I compare the xml file from both projects, they have different packages.

So do I need to add the packages from Project A into Project B as well ? If yes, how do I do that ?

Please help, I am very new to this

Code for Project B is as below

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="org.tensorflow.demo"
>

Code for Project A is as below

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.google.android.gms.samples.vision.ocrreader"
android:installLocation="auto" >

These are the files that I added from Project A to Project B Files from Project A ,

Added into Project B

the new error

Answer 1

This is one of the most common errors you get when you copy-paste Java classes from one project to another.

What you need to do is: You need to copy those three classes right? So, in Project B, make three new classes of the same name and each time copy paste the code of those three classes from Project A, just excluding the name of the package, which is in the first line of every class. Then compile the project B. Your errors should be resolved.