View Binder Support #1175

pmecho · 2021-04-26T05:41:28Z

Adds an EpoxyViewBinder class inside a new epoxy-viewbinder module that allows for using Epoxy models outside of recycler views. This has been used internally at Airbnb for a few years.

Additional changes:

Updated Robolectric to the latest due to Espresso hangs.
Updated Espresso to stable.
Modified the Model in the integration test module to update the view for Espresso testing.
Added a view binder to the kotlin-sample

Wiki documentation to come in a separate PR.

A special thanks to:

@elihart who was the original creator
@eboudrant for not only helping test and improve this branch but also for the foundation and inspiration for EpoxyViewBinderVisibilityTracker, which built off of the EpoxyVisibilityTracker.
Those who helped maintain this over the years:
- Andreas Rossbacher
- Jamie Ho
- Julia Fu
- Nathanael Silverman
- Sam Zhao
- Sherwin LI
- Tankery Chen
- Vinay Gaba

Add view binder to kotlin sample

…up (#1165) * Add epoxyView shortcut to ViewGroup * Add optionalEpoxyView for activity and view (with a minor refactor for less copy/paste) * switch to `androidx.core.app.ComponentActivity` Co-authored-by: Emmanuel Boudrant <eboudrant@netflix.com>

* Add view binder visibility tests * Add basic unit tests for the view binder * Gradle clean up * Can't use ComponentActivity directly with the current dependency version Co-authored-by: Peter Elliott <peter.elliott@airbnb.com>

* package="com.airbnb.epoxy.viewbinder" * import com.airbnb.epoxy.viewbinder.R

Some documentation tweaks

Add try/catch and fix up dependencies

Add newline

elihart

@pmecho looks pretty great overall! Just have some polish suggestions. Thanks for all your work on this and for adding such great test coverage, super exciting to finally be able to share this!

elihart · 2021-04-26T15:54:40Z

blessedDeps.gradle

@@ -19,6 +19,9 @@ rootProject.ext.ANDROIDX_RECYCLERVIEW = "1.1.0"
 rootProject.ext.ANDROIDX_MATERIAL = "1.0.0"
 rootProject.ext.ANDROIDX_APPCOMPAT = "1.0.0"
 rootProject.ext.ANDROIDX_CARDVIEW = "1.0.0"
+rootProject.ext.ANDROIDX_CORE_KTX = "1.0.0"


I think the latest version is 1.3.2 https://maven.google.com/web/index.html#androidx.core:core-ktx

or could use 1.5.0-rc01

This would probably bump up the app compat version though. Should we just increase the versions across the board for AndroidX?

Going to leave these as is and bump those versions in a separate PR in case there are issues.

elihart · 2021-04-26T16:01:52Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

+ * 2. You have a predefined view in a layout and you want to update its data functionally with an
+ * EpoxyModel
+ */
+class EpoxyViewBinder : EpoxyController() {


I think it would be much better to implement ModelCollector instead of extending EpoxyController. This removes some hackiness around extending the controller and is also more efficient since we don't need to create extra objects in the controller that are unused.

I meant to do this in our codebase and never got around to it

Would then need to replace all function receivers EpoxyController.() -> with ModelCollector.()

I think that would be pretty simple

Oo nice I'll try that out!

Yeah this is much cleaner now! I added an exception handler. Chose not to use the global one in the EpoxyController as that'd need an API change.

elihart · 2021-04-26T16:11:54Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

+            if (existingHolder == null || !model.hasSameViewType(existingHolder.model)) {
+                val newView = model.buildView(parentView)
+                newView.id = previousView?.id ?: ViewCompat.generateViewId()
+                parentView.addView(newView)


The kdoc seems wrong since it says it does not add the view to the parent [ViewGroup]

Nice catch. I'll figure out which is the intended behavior

Yeah it looks like this was just an error. Removed the line.

elihart · 2021-04-26T16:19:32Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

+fun ComponentActivity.epoxyView(
+    @IdRes viewId: Int,
+    useVisibilityTracking: Boolean = false,
+    initializer: LifecycleAwareEpoxyViewBinder.() -> Unit,


should initializer have a default empty lambda so it can be skipped?

elihart · 2021-04-26T16:20:00Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

+    @IdRes viewId: Int,
+    useVisibilityTracking: Boolean = false,
+    initializer: LifecycleAwareEpoxyViewBinder.() -> Unit,
+    modelProvider: EpoxyController.() -> Unit


it might be nice if we provided a context parameter to the modelProvider lambda

elihart · 2021-04-26T21:28:11Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

+fun Fragment.epoxyView(
+    @IdRes viewId: Int,
+    useVisibilityTracking: Boolean = false,
+    initializer: LifecycleAwareEpoxyViewBinder.() -> Unit,


I believe for completeness fallbackToNameLookup should be in the non optional functions too. I think we just didn't have that use case internally

elihart · 2021-04-26T21:29:46Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

+    initializer: LifecycleAwareEpoxyViewBinder.() -> Unit,
+    modelProvider: EpoxyController.() -> Unit
+) = LifecycleAwareEpoxyViewBinder(
+    (this.context as? LifecycleOwner) ?: error("LifecycleOwner required as view's context "),


I think there are cases where we may need to unwrap the context in case of ContextWrapper. We do this in EpoxyRecyclerView

private fun getContextForSharedViewPool(): Context { var workingContext = this.context while (workingContext is ContextWrapper) { if (workingContext is Activity) { return workingContext } workingContext = workingContext.baseContext } return this.context } ```

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

elihart · 2021-04-26T21:40:52Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

+        viewBinder.addInterceptor(interceptor)
+    }
+
+    /** Replaces the [View] with the model produced by the [modelProvider] lambda. */


is this more accurate?

Suggested change

/** Replaces the [View] with the model produced by the [modelProvider] lambda. */

/** Updates the [View] with the model produced by the [modelProvider] lambda. */

This is probably too simplistic of a kdoc for this function as it could either hide, replace, or update the view depending on the prior and new model. I'll update it.

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinderVisibilityTracker.kt

Co-authored-by: Eli Hart <eli.hart@airbnb.com>

Add exception handler Misc improvements based on PR comments

elihart

@pmecho looks great! thanks for the polish :)

elihart · 2021-05-03T17:06:38Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinder.kt

+ * `context` is a ContextWrapper it will continually unwrap it until it finds the Activity. If
+ * no Activity is found it will return the the view's context.
+ */
+private fun Context.getContextForSharedViewPool(): Context {


could rename this to unwrapContextForLifecycle.

Should the comment be updated since this no longer is used for view pools?

elihart · 2021-05-03T17:08:31Z

epoxy-viewbinder/src/main/java/com/airbnb/epoxy/EpoxyViewBinderVisibilityTracker.kt

+ *  * View binders in scrollable views will only forward the initial visibility state. New events
+ *  will not be emitted on scroll actions. This is due to not knowing when the outer view scrolls.
+ */
+class EpoxyViewBinderVisibilityTracker {


I suppose it's not feasible or worthwhile to share more of this code with the original visibility tracker?

Yeah unfortunately I think they're different enough that it'd be challenging to refactor them to share code. The original one is tightly coupled to working with a recycler view. Some methods are the same/close to the same but I don't think we gain much with the effort to consolidate with compose on the horizon.

Peter Elliott and others added 8 commits April 3, 2021 10:10

Initial addition of view binder classes

69458ae

Hook up visibility tracking

2e0f199

Add view binder to kotlin sample

Set packageid to com.airbnb.epoxy.viewbinder (#1172)

8a6e416

* package="com.airbnb.epoxy.viewbinder" * import com.airbnb.epoxy.viewbinder.R

Doc cleanup and refactors for line length

012336b

Move some extension functions to new file

94de08f

Some documentation tweaks

Add tests

fb06cc4

Add try/catch and fix up dependencies

pmecho requested a review from elihart April 26, 2021 05:41

Peter Elliott added 2 commits April 25, 2021 23:43

Fix dependency mismatch

ff6b603

Add newline

Add model update test

be5be08

elihart approved these changes Apr 26, 2021

View reviewed changes

pmecho and others added 2 commits April 27, 2021 09:35

Apply suggestions from code review

cf5b39d

Co-authored-by: Eli Hart <eli.hart@airbnb.com>

Convert to ModelCollector

ef6c0af

Add exception handler Misc improvements based on PR comments

elihart approved these changes May 3, 2021

View reviewed changes

Peter Elliott added 3 commits May 3, 2021 23:40

Fix comment and lint failures

5b35f6e

Don't use debugImplementation as CI runs release tests

2e4c429

Fix tests due to model collector swap

651d695

pmecho merged commit 35d3f77 into master May 8, 2021

elihart mentioned this pull request May 12, 2021

Release 4.6.0 #1184

Merged

elihart mentioned this pull request Jul 25, 2021

Is it possible to render fixed top or bottom views? #1213

Closed

elihart deleted the pmecho-view-binder branch May 19, 2023 19:32

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	/** Replaces the [View] with the model produced by the [modelProvider] lambda. */
	/** Updates the [View] with the model produced by the [modelProvider] lambda. */

View Binder Support #1175

View Binder Support #1175

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pmecho commented Apr 26, 2021

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