I came across what seemed to me like an oddity in the Files app on iPad OS and wanted to check if others had seen the same and if it was in fact expected behaviour.
If I restart my iPad, open the files app and tap on a text file in iCloud Drive then it opens in the default text viewer, which is what I would expect.
If I then long press on the file and use the Share option to open the file in Textastic then it opens that file in Textastic as you would expect, however, it also seems to set something in the files app so that any other text file you open also opens in Textastic rather than the default viewer.
If I then use the share option to open a text file in IA Writer then it starts opening all subsequent text files in IA Writer.
So basically it seems that the last app you use to open a text file in place becomes the default for opening subsequent text files.
Re-starting the iPad reverts to the original behaviour.
I can’t answer your question, but I’m grateful you posted this. I have never done the systematic testing you have, so Files’s default app has always been a mystery to me. Now I know how to get it to default to the app I want—assuming Apple doesn’t change the behavior.
Yes, that’s the behavior I see as well. It’s not intuitive, but it is, at least, predictable.
It gets especially weird when I do something like open a .docx in iA Writer (which converts the .docx to markdown). After that, tapping on a .docx in Files will open it in iA Writer until I “share” the file and choose to open it in Word.
I just found a wrinkle in this behavior. I opened an SVG file in Graphic (a vector drawing program like Affinity Designer) by starting in Files and choosing Share -> Copy to Graphic. This did not make Graphic the default app for SVG files. The next time I tapped on that same SVG file, it opened for viewing within Files.
I thought maybe there was a difference between “Open in …” and “Copy to …” So I long-pressed on that same SVG file and chose Share -> Open in Textastic. It opened in Textastic, as expected. But when I closed it in Textastic, went back to Files, and tapped on it, it opened for viewing within Files.
So maybe certain types of file are hard-wired to use the Files QuickLook feature no matter what we want.
I think that’s right as well. PDF files are another example where, most (all?) of the time, I have to “share” them to have them open in another app.
Perhaps its just files that you could annotate with the built-in markup tools that always open in Quicklook?
Thanks for the responses and confirming that this does indeed seem to be the current “normal” behaviour.
I also tried a few different file types and agree it only seems to work this way for some of them.
I suspect it won’t stay this way for too long as it has the feel of something that’s half implemented.
In the meantime it is quite a handy trick. I used it this afternoon to force Files to open a bunch .json file in the Jayson app.
I just wish I could find a way to force it back to the default viewer without the need to restart the device (I did try just restarting the Files app, but that doesn’t break the association).