Android autofill: dispatchProvideAutofillStructure() not laid out

Question

I have configured my app to support Android Oreo with compileSdkVersion 26. I've also set up android:autofillHints="phone" for my phone number input field. When I tap on the field, I can see "Autofill" popping up. However, when I tap on "Autofill", "Contents can't be autofilled" toast appears and I see the following trace in logcat:

RemoteFillService  Not handling { when=-3ms what=3 target=com.android.internal.os.HandlerCaller$MyHandler } as service for ComponentInfo{com.google.android.gms/com.google.android.gms.autofill.service.AutofillService} is already destroyed
View               dispatchProvideAutofillStructure(): not laid out, ignoring

How should I fix this? I've confirmed that I have the phone number configured in Settings > System > Languages & input > Advanced > Input assistance > Autofill service.

UPDATE with a sample XML: In API 26 emulator settings, I can select "Autofill with Google". Using the Design tab of Android Studio, I added a "Phone" type EditText, and then manually inserted android:autofillHints="phone" in the XML element:

<EditText
    android:id="@+id/editText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:ems="10"
    android:inputType="phone"
    android:autofillHints="phone" />

Logcat peculiarities described above can be observed using this XML.

Answer 1

I'm the Android Frameworks engineer leading the Autofill Framework project, so I'll answer some questions:

• The "Contents can't be autofilled" message typically means the Autofill Service does not know how to autofill the screen. When you're adding autofill support to your app, it's often easier to use an Autofill Service you can control first, rather than a "real" service like a password manager. As mentioned in a previous reply, we provide a sample service that can be used for this purpose.
• When you long-press a text field and select AUTOFILL, you are in fact "forcing" an autofill request as mentioned in another reply (i.e., behind the scenes the text field is calling AutofillManager.requestAutofill()). If the Autofill Service knows how to autofill your screen, you shouldn't need to do that, as the autofill suggestions would show up right away once you focus the input field.
• You shouldn't need to set importantForAutofill or call AutofillManager.cancel() in your case.

So, my recommendation is to try to use the sample Autofill Service implementation to test your app first. Most likely, the first time you access your app the autofill popup won't be shown because the service does not have data for it. But once your app triggers the save UI (for example, after you manually enter the phone number and the activity finishes) and you tap save, that data should be available the next time you launch the activity.

Hope that helps,

-- Felipe