Android Question Android Information for Newbies - Like me

[AlexOfOz]

I post information as I bump into it for people who are so new, they are too timid to ask the question. I understand entirely and have no shame ..... If I don't know, I'll ask.

This is to do with Android not differentiating between upper and lower case.

I am currently working on an app for an Android phone that has lots and lots of mp3 files that I have obtained from GITHUB. Their names contain both upper and lower case and worked beautifully with B4J.

However, when I came across to build a similar app on my Android phone, I ran into all sorts of frustration associated with DirAssets. Even after renaming every file to remove all upper case, the problem continued to happen.

Eventually I eliminated all possible sources of continuing problems, but was still facing the same frustration. That's when it occurred to me that the phone might be holding on to the existing files in DirAssets and, because it doesn't recognise the difference between upper and lower case, wasn't replacing them, no matter how hard I tried.

The answer was to turn the phone off, then restart it. In doing so I must have cleared DirAssets, allowing the next run of the program to reload the now all lower case mp3 files. And it worked.

I hope this has helped a silent person out there.

Alex

 

[teddybear]

I wonder which folder mp3 files you obtained are put into, DirAssets?

 

[DonManfred]

DirAssets?

He wrote it already. Yes.

 

[teddybear]

He wrote it already. Yes.

The name of all files in DirAsset it seems to have been converted to lowercase by B4A, so I asked that

 

[AlexOfOz]

The name of all files in DirAsset it seems to have been converted to lowercase by B4A, so I asked that

No, it appears that the names of the files weren't converted to lower case. I did a ListFiles on DirAssests and the mp3's were all there in upper and lower. That was one of the things confusing me, because when I tried to load new, lowercase file names, Android said they were already there and didn't replace them. Very confusing.

 

[DonManfred]

converted to lowercase by B4A

The resource compiler converts names to lower case before processing to avoid problems on case-insensitive file systems
Use only lower cased files names.

https://developer.android.com/guide/topics/resources/providing-resources

So i guess the convert to lowercase is part of the Android SDK itself. Not B4A.

 

[teddybear]

No, it appears that the names of the files weren't converted to lower case. I did a ListFiles on DirAssests and the mp3's were all there in upper and lower. That was one of the things confusing me, because when I tried to load new, lowercase file names, Android said they were already there and didn't replace them. Very confusing.

It's weird, I don't think they are case sensitive in DirAssests, do you play mp3 that is in DirAssets?

 

[AlexOfOz]

It's weird, I don't think they are case sensitive in DirAssests, do you play mp3 that is in DirAssets?

Yes. The action of the program is working fine. A button which activates an mp3 from DirAssets

 

[teddybear]

when I tried to load new, lowercase file names, Android said they were already there and didn't replace them.

I don't understand what you mean, why said they were already there and didn't replace them.

 

[AlexOfOz]

I don't understand what you mean, why said they were already there and didn't replace them.

They were already in DirAssets as upper and lower case, but when I renamed them in the program to be all lower case, then reran the program, Android saw the names in DirAssets - the upper and lower case ones - as being the same as those in the program - the lower case ones. And because it thought they were the same it didn't bother replacing the ones in DirAssets. That is the final point of my original post; in order to clear them out of DirAssets, I needed to turn the phone off then back on. That cleared DirAssets of the upper and lower case mp3's, allowing the new lower case ones to be written to DirAssets when I ran the program again.

 

[teddybear]

Rename, how do you do rename?

 

[AlexOfOz]

Rename, how do you do rename?

The mp3 modules are hard coded in the program. Button 32 uses abc.mp3. The name of the modules was a tad convoluted when I downloaded them, but the module's use was coded into the name, so I didn't change it. The only change I made was to change all upper case to lower case .... in the program files and in the program. The final step was to remove them from DirAssets, as discussed above.

This journey of identifying the root cause of the problem, then determining the numerous steps I needed to take to over come it was long, frustrating, but ultimately fruitful. I've learned a lot and hopefully this post can remove some of the time and angst for others. I have seen that I'm not the first to bump into this situation, and I have read some joyful accounts of "clever" ways of getting past it. I always prefer the simple approach if there is one, and having everything lower case for Android is the simple solution, but it only works if the DirAssets is cleared of the earlier upper and lower case ones.

 

[Computersmith64]

I think cleaning the project in the B4A IDE before you compile will also force the assets to be re-copied (but I could be wrong).

Fyi - Android filenames *are* case sensitive but the OS will ignore case when handling files from case insensitive file systems.

- Colin.

 

[teddybear]

The mp3 modules are hard coded in the program. Button 32 uses abc.mp3. The name of the modules was a tad convoluted when I downloaded them, but the module's use was coded into the name, so I didn't change it. The only change I made was to change all upper case to lower case .... in the program files and in the program. The final step was to remove them from DirAssets, as discussed above.

Thank you for sharing the solution.
I couldn't find rename method in File, so I was curious to ask you how do rename, after read this, I guess it is that copy mp3 to another folder then delete it from assets, is that?

 

[AlexOfOz]

Thank you for sharing the solution.
I couldn't find rename method in File, so I was curious to ask you how do rename, after read this, I guess it is that copy mp3 to another folder then delete it from assets, is that?

In simple words, yes. The rename of the mp3 modules was done on the laptop, not within the program. Of course, all references to them in the program needed to be made lower case, but that wasn't how I changed the names. It was simply a case of renaming every one in the laptop folder, then adding them to the program in the standard way.

 

[RodM]

They were already in DirAssets as upper and lower case, but when I renamed them in the program to be all lower case, then reran the program, Android saw the names in DirAssets - the upper and lower case ones - as being the same as those in the program - the lower case ones. And because it thought they were the same it didn't bother replacing the ones in DirAssets. That is the final point of my original post; in order to clear them out of DirAssets, I needed to turn the phone off then back on. That cleared DirAssets of the upper and lower case mp3's, allowing the new lower case ones to be written to DirAssets when I ran the program again.

You know that DirAssets is read only, don't you? You can't rename, or change any files there, within the app.

 

[AlexOfOz]

You know that DirAssets is read only, don't you? You can't rename, or change any files there, within the app.

I certainly do now, that's for sure. Now it is clear that also includes replacing existing files in there, or deleting files from there, hence the need to turn off the phone to clear it. The main point of this post was to highlight the confusion that can come from Android not accepting upper and lower case and the weird way it handles it. So long as people know about this potentially confusing situation, they'll know what to do if their files aren't working. Rename them on the laptop to all lower case, then turn the phone off and back on. Run the program again from the laptop and it will reload the renamed files and Android will handle them correctly.

 

[josejad]

I had a similar problem here

Signature Capturing with jSignature and WebViewExtras

Hi everyone: After several test, now I can use the jSignature javascript plugin I was using in my web, in my B4A app, in order to update my database from b4a the same way I'm doing in my web. I know there are some solutions to do this in B4A, but I need to do it this way because I was using it...

www.b4x.com

 

[Adrian Jansen]

Not directly related, but you might find its better to put the names of all files you want to use in a list, adjusting cases as needed. Put the file list in DirAssets too, and then read that first. That way you dont have to hard-code filenames in your code. Much more flexible.

 

[AlexOfOz]

Not directly related, but you might find its better to put the names of all files you want to use in a list, adjusting cases as needed. Put the file list in DirAssets too, and then read that first. That way you dont have to hard-code filenames in your code. Much more flexible.

Excellent idea. Thanks for the suggestion. I did a similar trick for my home-grown WORDLE program. Not DirAssets, but a place that makes it very convenient.