Android P (API 28) - What does the StrictMode policy violation "SmartSelectionEventTracker$SelectionEvent;->selectionAction" mean?

android reflection android-strictmode
hamena314 picture hamena314 · Aug 23, 2018 · Viewed 22.9k times · Source

I am using the StrictMode in order to find non-SDK usages:

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

Now I am getting a policy violation:

D/StrictMode: StrictMode policy violation: android.os.strictmode.NonSdkApiUsedViolation: Landroid/view/textclassifier/logging/    SmartSelectionEventTracker$SelectionEvent;->selectionAction(IIILandroid/view/textclassifier/TextClassification;)Landroid/view/textclassifier/logging/    SmartSelectionEventTracker$SelectionEvent;
        at android.os.StrictMode.lambda$static$1(StrictMode.java:428)
        at android.os.-$$Lambda$StrictMode$lu9ekkHJ2HMz0jd3F8K8MnhenxQ.accept(Unknown Source:2)
        at java.lang.Class.getDeclaredMethodInternal(Native Method)
        at java.lang.Class.getPublicMethodRecursive(Class.java:2075)
        at java.lang.Class.getMethod(Class.java:2063)
        at java.lang.Class.getMethod(Class.java:1690)
        at bzi.a(SourceFile:11)
        at bzq.a(SourceFile:12)
        at org.chromium.content.browser.selection.SmartSelectionClient.<init>(SourceFile:5)
        at bzZ.a(Unknown Source:7)
        at org.chromium.android_webview.AwContents.e(SourceFile:193)
        at org.chromium.android_webview.AwContents.d(SourceFile:153)
        at org.chromium.android_webview.AwContents.<init>(SourceFile:81)
        at uY.run(SourceFile:15)
        at ahv.a(SourceFile:13)
        at ahw.run(SourceFile:2)
        at org.chromium.base.ThreadUtils.b(SourceFile:31)
        at ahv.a(SourceFile:7)
        at com.android.webview.chromium.WebViewChromiumFactoryProvider.b(SourceFile:6)
        at com.android.webview.chromium.WebViewChromium.init(SourceFile:111)
        at android.webkit.WebView.<init>(WebView.java:678)
        at android.webkit.WebView.<init>(WebView.java:604)
        at android.webkit.WebView.<init>(WebView.java:587)
        at android.webkit.WebView.<init>(WebView.java:574)
        at java.lang.reflect.Constructor.newInstance0(Native Method)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:343)
        at android.view.LayoutInflater.createView(LayoutInflater.java:647)
        at com.android.internal.policy.PhoneLayoutInflater.onCreateView(PhoneLayoutInflater.java:58)
        at android.view.LayoutInflater.onCreateView(LayoutInflater.java:720)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:788)
        at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
        at android.view.LayoutInflater.rInflate(LayoutInflater.java:863)
        at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
        at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
        at com.mine.ui.events.EventScreen.onCreateView(EventScreen.java:70)
        at android.support.v4.app.Fragment.performCreateView(Fragment.java:2354)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1419)
        at android.support.v4.app.FragmentManagerImpl.moveFragmentToExpectedState(FragmentManager.java:1740)
        at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1809)
        at android.support.v4.app.BackStackRecord.executeOps(BackStackRecord.java:799)
        at android.support.v4.app.FragmentManagerImpl.executeOps(FragmentManager.java:2580)
        at android.support.v4.app.FragmentManagerImpl.executeOpsTogether(FragmentManager.java:2367)
        at android.support.v4.app.FragmentManagerImpl.removeRedundantOperationsAndExecute(FragmentManager.java:2322)
        at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:2229)
        at android.support.v4.app.FragmentManagerImpl.executePendingTransactions(FragmentManager.java:781)
        (... shortened ...)

The important line is:

at com.mine.ui.events.EventScreen.onCreateView(EventScreen.java:70)

Examining the mentioned line:

public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
{
// This is the important line:
ViewGroup content = (ViewGroup) inflater.inflate(R.layout.mine_event, container, false);
WebView webView = (WebView) content.findViewById(R.id.container);
webView.loadUrl(event.getWebViewUrl());
webView.getSettings().setJavaScriptEnabled(true);
(...)

So I get the violation while the inflation happens, which I dont quite understand.

As you can see shortly after the mentioned line a WebView comes into play. I have looked at the source-code for the SmartSelectionEventTracker here and it seems like a generic class for Widgets like TextViews, WebViews, .... WebViews seem to be related to MockViews which are related to TextViews.

But apart from that finding I do not understand how / why the violation is happening and what I can do against it.

Can someome explain this to me?

Answer

Kevin Coppock picture Kevin Coppock · Aug 23, 2018

In Android P, restrictions have been added to private APIs (that is, APIs that are not part of the public SDK and are accessed via reflection). See Restrictions on non-SDK interfaces:

Android 9 (API level 28) introduces new restrictions on the use of non-SDK interfaces, whether directly, via reflection, or via JNI. These restrictions are applied whenever an app references a non-SDK interface or attempts to obtain its handle using reflection or JNI. For more information about this decision, see Improving Stability by Reducing Usage of non-SDK Interfaces.

So that's what you're seeing -- it's a warning that something is accessing one of those private APIs that may be removed in the future. However, the stack trace shows, as you mentioned, that this is coming from the WebView. In particular, during the initialization of SmartSelectionClient. That initializes a native library that implicitly is accessing SmartSelectionEventTracker, which is marked with @hide in its Javadoc statement, which indicates it is not part of the public SDK.

In short, there's likely nothing you can do about this particular warning, so I wouldn't worry about it. It's happening in the device's Chromium WebView implementation, so it's outside of your application's control. As both Android and Chromium are published by Google, if there is a legitimate issue in a future release, an update will be published to the WebView implementation before it becomes a problem.

Related questions

Is it possible to dynamically load a library at runtime from an Android application?

Is there any way to make an Android application to download and use a Java library at runtime? Here is an example: Imagine that the application needs to make some calculations depending on the input values. The application asks for …

Read More
The setMobileDataEnabled method is no longer callable as of Android L and later

I have logged Issue 78084 with Google regarding the setMobileDataEnabled() method being no longer callable via reflection. It was callable since Android 2.1 (API 7) to Android 4.4 (API 19) via reflection, but as of Android L and later, even with root, the setMobileDataEnabled() method …

Read More
Proguard and reflection in Android

I have just used proguard, but classes I am trying to instantiate via reflection are not working. I have an interface Algorithm I pass classes like this AlgorithmFactory.SomeClassThatExtendsAlgorithmImpl.class The class is instantiated like this public ArrayList<Algorithm&…

Read More