86 lines
2.7 KiB
Kotlin
86 lines
2.7 KiB
Kotlin
package org.mozilla.fenix.components
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import android.view.View
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import android.view.ViewStub
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import androidx.annotation.UiThread
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import mozilla.components.support.base.feature.UserInteractionHandler
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import mozilla.components.support.base.feature.LifecycleAwareFeature
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import java.lang.ref.WeakReference
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/**
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* A base feature class that enables lazy inflation of a view needed by a feature.
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*
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* When a feature needs to be launched (e.g. by user interaction) calling [launch]
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* will inflate the view only then, start the feature, and then executes [onLaunch]
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* for any feature-specific startup needs.
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*/
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abstract class InflationAwareFeature(
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private val stub: ViewStub
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) : LifecycleAwareFeature, UserInteractionHandler {
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internal lateinit var view: WeakReference<View>
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internal var feature: LifecycleAwareFeature? = null
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private val stubListener = ViewStub.OnInflateListener { _, inflated ->
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view = WeakReference(inflated)
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feature = onViewInflated(inflated).also {
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it.start()
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onLaunch(inflated, it)
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}
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}
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/**
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* Invoked when a view-dependent feature needs to be started along with the feature itself.
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*/
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@UiThread
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fun launch() {
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// If we have a feature and view, we can launch immediately.
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if (feature != null && view.get() != null) {
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onLaunch(view.get()!!, feature!!)
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} else {
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stub.apply {
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setOnInflateListener(stubListener)
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inflate()
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}
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}
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}
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/**
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* Implementation notes: This implemented method does nothing since we only start the feature
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* when the view is inflated.
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*/
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override fun start() {
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feature?.start()
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}
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override fun stop() {
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feature?.stop()
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}
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/**
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* Called when the feature gets the option to handle the user pressing the back key.
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*
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* @return true if the feature also implements [UserInteractionHandler] and the feature has
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* been initiated.
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*/
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override fun onBackPressed(): Boolean {
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return (feature as? UserInteractionHandler)?.onBackPressed() ?: false
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}
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/**
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* Invoked when the view has been inflated for the feature to be created with it.
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*
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* @param view The newly created view.
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* @return The feature initiated with the view.
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*/
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abstract fun onViewInflated(view: View): LifecycleAwareFeature
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/**
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* Invoked after the feature is instantiated. If the feature already exists,
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* this is invoked immediately.
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*
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* @param view The view that is attached to the feature.
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* @param feature The feature that was instantiated.
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*/
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abstract fun onLaunch(view: View, feature: LifecycleAwareFeature)
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}
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