I am currently learning about the Conductor framework for Android and have a bit of a problem or misunderstanding of how it works.
I was under the impression that the method
setRetainViewMode(RetainViewMode.RETAIN_DETACH);
would save the states of the views in the controller. To test the behaviour, I added EditText views, entered a value in it and rotated the screen. I also added 2 views with onclick listeners attached, changing the background color onclick
The result of the test was that the EditText views maintained the state and preserved the entered values. But the 2 views, changed back to their original background color (none).
This is the behaviour of the views regardless on which RetainViewMode is set
I have this simple MainActivity (note: I'm writing in Kotlin):
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
var router: Router = Conductor.attachRouter(this, controller_container, savedInstanceState)
if (!router.hasRootController()) {
var t : TestController = TestController()
t.retainViewMode = Controller.RetainViewMode.RETAIN_DETACH
router.setRoot(RouterTransaction.with(t))
}
}
companion object doTask {
fun start(activity : Activity) {
val intent = Intent(activity, MainActivity::class.java)
activity.startActivity(intent)
}
}
}
And here is the the TestController:
class TestController : BaseController() {
var i : Int = 0
var h : Int = 0
override fun onViewBound(view: View) {
view.a.setOnClickListener {
i++
if (i % 2 == 0) {
view.a.setBackgroundColor(ContextCompat.getColor(applicationContext, R.color.white))
} else {
view.a.setBackgroundColor(ContextCompat.getColor(applicationContext, R.color.turtle_green))
}
}
view.b.setOnClickListener {
h++
if (h % 2 == 0) {
view.b.setBackgroundColor(ContextCompat.getColor(applicationContext, R.color.white))
} else {
view.b.setBackgroundColor(ContextCompat.getColor(applicationContext, R.color.blue_light))
}
}
}
override fun inflateView(inflater: LayoutInflater, container: ViewGroup): View {
return inflater.inflate(R.layout.controller_layout_test, container, false)
}
}
And xml layout file controller_layout_test:
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<requestFocus></requestFocus>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:src="@drawable/logo_simple"/>
<ScrollView
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout
android:layout_width="300dp"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_margin="30dp"
android:layout_gravity="center"
android:background="@color/transparent50p"
android:padding="20dp">
<EditText
android:id="@+id/gt"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_gravity="center"
android:layout_marginTop="10dp"
android:padding="6dp"
android:background="@color/white_transparent50p"/>
/>
<EditText
android:id="@+id/erergeargf"
android:layout_width="match_parent"
android:layout_height="40dp"
android:layout_gravity="center"
android:layout_marginTop="10dp"
android:padding="6dp"
android:background="@color/white_transparent50p"/>
<View
android:id="@+id/a"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_margin="5dp"
android:layout_gravity="center"></View>
<View
android:id="@+id/b"
android:layout_width="50dp"
android:layout_height="50dp"
android:layout_margin="5dp"
android:layout_gravity="center"></View>
</LinearLayout>
</ScrollView>
</FrameLayout>
activity_main xml layout looks like this:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="dk.minreklame.minetilbud_v2.MainActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:id="@+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
/>
</android.support.design.widget.AppBarLayout>
<com.bluelinelabs.conductor.ChangeHandlerFrameLayout
android:id="@+id/controller_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="@string/appbar_scrolling_view_behavior"
/>
</android.support.design.widget.CoordinatorLayout>
As your views have references to the host Activity, they will never be retained across orientation changes. That would cause a memory leak. The docs on RETAIN_DETACH state:
The Controller will retain its reference to its view when detached, but will still release the reference when a config change occurs.