Recommended approach for handling errors across process using AIDL (Android)
aidl, android, android-binder, java
Solution
Your remote method can return a `Parcel` that contains the result data or an Exception if there is an error. See the `Parcel#writeException` method. I believe that this is how Android exceptions make it back when performing actions on a `ContentProvider` that lives in another process. There are many ways to return the result data including using the `Bundle` class.
Your manager class can hide the implementation details by unparcelling and returning the data or throwing the unparcelled exception so users never interact with the `Parcel`.
Here is a link to the source for `Parcel#writeException`.
Problem
I have a binder service and a client that live in different processes. Using AIDL, when the client calls into my remote binder service, there are times that I need to relay an error (exception) back to the client. However, from my understanding, this is not possible. I tried throwing a "RemoteException" from my binder service to see what will happen, and I get Uncaught remote exception! (Exceptions are not yet supported across processes.) in my logcat. Since it looks like this is not possible, what is the best approach for informing the client of an error? I was thinking I can just convert my AIDLs to use C-style interfaces in which I just return an error code (and 0 on success), but this looks ugly. Is there a better approach?