Activity theme not applied into child views

[gumil]

Activity theme not applied into child views Child views does not inherit activity theme might be because setContentView is not called.

To Reproduce I have created all views programmatically and does not depend on XML. Issues found so far:

1. Child views did not inherit colors from theme
2. selectableItemBackground does not resolve ripple animation since it does not get the right theme.

Expected behavior Activity theme should be applied into child views

Environmental info (please complete the following information):

• Library version: 1.0.0
• Device: Pixel 3 x86 emulator
• OS: Android 10

[nhaarman]

Could you provide some sample code of how you're creating the views?

Note that views should be created using the Activity context which contains the proper theme, and when not created from XML you should pass the proper defStyleAttr to the View's constructor (e.g. android.R.attr.textViewStyle for TextView).

Whether or not setContentView is used should not play any role here.

[gumil]

Views are created using ViewProvidingScene's createViewController parent context parameter. The colors were not inherited like colorPrimary when Acorn was used. But setting the view directly to setContentView it got the right colors.

[nhaarman]

Are you using AcornAppCompatActivity?

[gumil]

Yes, and I am relying to the colorPrimary etc.

[nhaarman]

Hm, this should work actually. The parent: ViewGroup provided in ViewProvidingScene is derived from the FrameLayout provided by the system through android.R.id.content, which obviously contains the theme info as necessary.

Activity.setContentView delegates to PhoneWindow.setContentView, which uses the same Activity context instance as provided through the parent instance, so there's no further magic happening there to make themes work.

Without a reproducible example there's not really much to go on from here. Would it be possible to create a sample project that consistently reproduces the issue?

[gumil]

With Acorn Scenes:

class MainActivity : AcornAppCompatActivity() {
    override fun provideNavigatorProvider(): NavigatorProvider {
        return DemoNavigatorProvider
    }
}

setContentView:

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(HomeView(this, DemoModel.values().toList()))
    }
}

The whole code is here https://github.com/gumil/acorn-demo

[nhaarman]

Thanks! That should help a lot.

[nhaarman]

The issue is more easily reproduced like so:

class MainActivity : AppCompatActivity() {

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        //setContentView(TextView(this).apply { text = "HELLO WORLD" })
        setContentView(TextView(findViewById<ViewGroup>(R.id.content).context).apply { text = "HELLO WORLD" })
    }
}

The assumption I made earlier is that the Context passed was the same instance in both cases seems to be wrong: the second instance (from the android.R.id.content View) is a ContextThemeWrapper. The baseContext of this wrapper is in fact the MainActivity instance, so this 'fixes' the theming issue again:

 val context = (findViewById<ViewGroup>(R.id.content).context as ContextThemeWrapper).baseContext
 setContentView(TextView(context).apply { text = "HELLO WORLD" })

[nhaarman]

It seems AppCompat does some hacky things under the hood, by removing the android.R.id.content id from the original View and applying it to its own view:

https://android.googlesource.com/platform/frameworks/support/+/d25af35/v7/appcompat/src/android/support/v7/app/AppCompatDelegateImplV7.java#390

// Change our content FrameLayout to use the android.R.id.content id.
// Useful for fragments.
decorContent.setId(View.NO_ID);
abcContent.setId(android.R.id.content);

This abcContent View is created using an 'emulated' ContextThemeWrapper:

/**
--
* This needs some explanation. As we can not use the android:theme attribute
* pre-L, we emulate it by manually creating a LayoutInflater using a
* ContextThemeWrapper pointing to actionBarTheme.
*/
TypedValue outValue = new TypedValue();
mContext.getTheme().resolveAttribute(R.attr.actionBarTheme, outValue, true);
themedContext = new ContextThemeWrapper(mContext, outValue.resourceId);

This ContextThemeWrapper is the instance we're seeing in our issue here, which resolves to the ActionBarTheme and not the app's theme..

I'm not sure yet why LayoutInflater.from that ContextThemeWrapper uses proper theming though (which is why I haven't seen this issue before).

[nhaarman]

A quick-and-dirty fix could be to insert a FrameLayout in between with the proper Context instance like so:

class MainActivity : AcornAppCompatActivity() {

    private lateinit var rootView: ViewGroup

    override fun onCreate(savedInstanceState: Bundle?) {
        rootView = FrameLayout(this)
        setContentView(rootView)
        super.onCreate(savedInstanceState)
    }

    override fun provideNavigatorProvider(): NavigatorProvider {
        return DemoNavigatorProvider
    }

    override fun provideRootView(): ViewGroup {
        return rootView
    }
}

I'll see and find if there's a 'proper' fix for this, or if something like this will be included in AcornAppCompatActivity.

[gumil]

Thank you for further investigating this!

I think this workaround works. Seems also like an edge case since I am just experimenting on Acorn and programmatic views with Contour. I just have this idea that when Jetpack Compose is released, programmatic views will be more common.

[nhaarman]

Yeah it's a basic case that really should work though. Thanks again for the repro!

[nhaarman]

An investigative issue on the android tracker: https://issuetracker.google.com/issues/141726320