Android P displaying API compatibility error message

Question

Running an app built against SDK level 27 on Android P somewhat unpredictably displays the following dialog (the dialog title is the name of the application):

Detected problems with API compatibility (visit g.co/dev/appcompat for more info)

The URL leads to this page about restrictions on non-SDK interfaces. My application doesn't use reflection itself, but it does use Gson.

There are no immediately obvious log messages in Logcat, except may messages such as:

Accessing hidden field Landroid/widget/AbsListView;->mIsChildViewEnabled:Z (light greylist, reflection)

When you are using SDK 27 and targeting <= 27, do you get this message on an actual device (Pixel) or just in the emulator? TIA — OferR, Aug 20 '18 at 03:19
I got this on an actual device (Pixel 2016) running at the time a preview version of Android P. — Paul Lammertsma, Aug 20 '18 at 09:04

score 12 · Accepted Answer · answered Jul 06 '18 at 12:36

Turns out that one of my Gson models exposed a getter that returned File. Gson uses reflection to recursively inspect the fields of classes, and in doing so, violates the reflection of disallowed SDK interfaces.

Reading the restriction document linked in the question got me to take a closer look at the log messages, and sure enough, one caught my attention:

Accessing hidden field [...] (dark greylist, reflection)

I don't recall exactly the message, but the point here is that it was in the dark greylist.

I discovered this by targeting SDK level 28 and enabling the new StrictMode feature detectNonSdkApiUsage(), upon which my application would crash with a stack trace:

if (BuildConfig.DEBUG && Build.VERSION.SDK_INT >= Build.VERSION_CODES.P) {
    StrictMode.setVmPolicy(new StrictMode.VmPolicy.Builder()
            .detectNonSdkApiUsage()
            .penaltyLog()
            .build());
}

The stack trace wasn't immediately insightful, but it pointed me in the right direction.

where did you put this code at? in the activity that failed? — Nigel Brown, Nov 22 '18 at 13:37
In my case, I put it in the Application's `onCreate()`, but you may also invoke it in the Activity's creation. — Paul Lammertsma, Nov 22 '18 at 13:38
cool thanks man the fix for me was just targeting android sdk 28 and then changing my build tools to the latest 28.0.2 — Nigel Brown, Nov 22 '18 at 14:44

score 2 · Answer 2 · answered Jan 15 '19 at 01:30

in you application class in the method onCreate() init this method can be close this dialog.

private void closeAndroidPDialog(){
    try {
        Class aClass = Class.forName("android.content.pm.PackageParser$Package");
        Constructor declaredConstructor = aClass.getDeclaredConstructor(String.class);
        declaredConstructor.setAccessible(true);
    } catch (Exception e) {
        e.printStackTrace();
    }
    try {
        Class cls = Class.forName("android.app.ActivityThread");
        Method declaredMethod = cls.getDeclaredMethod("currentActivityThread");
        declaredMethod.setAccessible(true);
        Object activityThread = declaredMethod.invoke(null);
        Field mHiddenApiWarningShown = cls.getDeclaredField("mHiddenApiWarningShown");
        mHiddenApiWarningShown.setAccessible(true);
        mHiddenApiWarningShown.setBoolean(activityThread, true);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

but this is dangerous this way is just make you can't see the dialog.

"mHiddenApiWarningShown" reflection working, but why add "android.content.pm.PackageParser$Package" reflection? What is the purpose? — codezjx, Jun 19 '20 at 04:31

Android P displaying API compatibility error message

2 Answers2