[Android Q&A, Help & Troubleshooting] RealWelder:
You will need some tools. Apk files are similar to zip files, but there are some things that are hidden. You will need apktool, adb, Notepad++, and java jdk installed. Adb and apktool are simple files that I can provide for you. They run on the command line in windows. What I do is put the files associated with adb and apktool in the C:\Windows directory so that they are installed system wide, meaning you can open the command prompt from anywhere and use the tools. Java jdk you will have to download and install.

I'm pretty sure on remix it will be framework-res.apk and it will be located in /system/framework/ directory. Apktool you will use to decompile and recompile the app. Adb is just to make things faster. You can use it to push or pull files from computer to phone and vice versa, reboot the phone, etc. You will have to enable USB Debugging in the developer options. You can also use adb to open a shell. (Like terminal in linux) but for our purposes we probably won't get into that.

Here is a link to my basic modding tools. Extract the files out and copy them to C:\Windows\.

https://drive.google.com/file/d/1Ywa3SWd_420uO-nyi2-iqVWp1vu0V_D9/view?usp=drivesdk

You'll need to copy any app that might be in /system/framework. I'm not super familiar with remix but we will get through it. Most likely it will be framework-res.apk unless remix uses something like RRframework-res or something. You can check that out with a root file manager. You may also need your SystemUI.apk located in /system/priv-app/. This is just to install the frameworks into the apktool.

Once you get all of your tools in place, create a folder named workspace on your desktop or somewhere easy to get to. Copy the above mentioned apk files into that folder. Next hold shift and right click the mouse. You want to open a command window here. In the command window type

apktool if framework-res.apk (then hit enter)

This is how you install the frameworks for apktool the if means install framework. You may also have to do this with SystemUI.apk.

Now were ready to decompile our framework! Lol. In cmd type

apktool d framework-res.apk

This will decompile the app. After you make your edits, you will use

apktool b framework-res

To build the app. (If you have any errors decompiling/recompiling report here)

At this point hopefully your app is decompiled and we can make our edit. Open /res/values/styles.xml with Notepad++ (a great computer program for coding) You will want to scroll down to Theme.Material.Light and find the TimePickerDialog. Then scroll down to Theme.Holo.Light and find TimePickerDialog. Copy the attribute from Holo theme to Material theme. Save. Recompile app. The new app will be located in the "dist" folder. Open the app with 7zip and add in the AndroidManfiest.xml and meta folder from the originals folder to retain the app's stock signature. Now we need to move our new apk to the phone. Type

adb push (drag and drop apk into cmd window) /sdcard/

This should push the app to the phone.

You can also use

adb pull (path and file)

to pull files from the phone to your workspace.

Once you get your new apk file ready and pushed onto the /sdcard/, open root file explorer and rename it to framework-res1.apk. This is so we can copy it into /system/framework/ without immediately overwriting the original. Next use root file explorer to change app's permissions to 0644. Once the permissions are changed correctly you can rename it to framework-res.apk and overwrite the original. Then reboot and enjoy.