Fallback URL (or other behaviour) for links where URI not supported

[Mark Carter]

In my template I have links like `<a href="myappscheme:path/to/uri">Click Me</a>`. However these links will obviously not work if my app is not installed. Is there a way to take the user to the app install page on Google Play, for example?

[Flavio Lerda]

Hello,

As far as I know, there is no way to specify a fallback for a URI.

I would suggest trying out using either:

  http://developer.android.com/reference/android/content/Intent.html#URI_ANDROID_APP_SCHEME

or:

  http://developer.android.com/reference/android/content/Intent.html#URI_INTENT_SCHEME

instead of a custom scheme.

These should be guarantee to open your app and not another app, and should open the Google Play Store if the app is not installed.

I have not checked in a while, so cannot speak in details to the exact behavior, but should help in your case.

Hope this helps,

Flavio

On Wed, 20 Apr 2016 at 06:24 Mark Carter <ma...@marcardar.com> wrote:

In my template I have links like `<a href="myappscheme:path/to/uri">Click Me</a>`. However these links will obviously not work if my app is not installed. Is there a way to take the user to the app install page on Google Play, for example?

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[Mark Carter]

Thanks Flavio, that's really useful. I'd totally forgotten about Dianne Hackborn reminding devs (6 years ago) not to use custom schemes!

I've tested out both the intent: and android-app: schemes and they work-ish (but I don't think as intended).

AnkiDroid (I'm using the version on Play Store) kicks off an "android.intent.action.VIEW" intent with the "intent:" or "android-app:" uri as the data.  I was expecting AnkiDroid to resolve it using Intent.parseUri() and then start an activity using that.

So, to get this working, I needed to add the following to my intent-filter (this feels wrong):

<action android:name="android.intent.action.VIEW" />

<data android:scheme="intent"/> or <data android:scheme="android-app" android:host="com.mycompany.myapp"/>

The "intent:" one is particularly bad because that would catch all "intent:" uris.  The fact that no other apps on my device support this "intent:" uri (no Intent chooser comes up) suggests that AnkiDroid is not handing the intent uri properly. The "android-app:" scheme is handled by the Google App which presumably is responsible for choosing whether forward the uri to the app or Play Store app.  Curiously if I let Google App handle the uri then the Play Store opens but with a blank screen.

Any pointers as to which part of the AnkiDroid code handles such intents, so I can take a look?

[Mark Carter]

I found the relevant code in AnkiDroid, and made a new PR.