Split ImagePreviewView into an interface and an implementation

As a preparation step for an alternative image preview UI, introduce a
generic interface for the image preview widget.

Flag: IntentResolver package entirely behind the CHOOSER_UNBUNDLED which
is in teamfood

Bug: 262280076
Test: manual testing
Change-Id: Ia7ddeb0c48790195e854af1d4b9a7376fa5e3421

3 files changed, 180 insertions, 144 deletions

diff --git a/java/src/com/android/intentresolver/ChooserContentPreviewUi.java b/java/src/com/android/intentresolver/ChooserContentPreviewUi.java
index 88f9006f..27645da4 100644
--- a/java/src/com/android/intentresolver/ChooserContentPreviewUi.java
+++ b/java/src/com/android/intentresolver/ChooserContentPreviewUi.java
@@ -358,7 +358,7 @@ public final class ChooserContentPreviewUi {
         if (imageUris.size() == 0) {
             Log.i(TAG, "Attempted to display image preview area with zero"
                     + " available images detected in EXTRA_STREAM list");
-            imagePreview.setVisibility(View.GONE);
+            ((View) imagePreview).setVisibility(View.GONE);
             onTransitionTargetReady.accept(false);
             return contentPreviewLayout;
         }
diff --git a/java/src/com/android/intentresolver/widget/ChooserImagePreviewView.kt b/java/src/com/android/intentresolver/widget/ChooserImagePreviewView.kt
new file mode 100644
index 00000000..dd1dd286
--- /dev/null
+++ b/java/src/com/android/intentresolver/widget/ChooserImagePreviewView.kt
@@ -0,0 +1,175 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.intentresolver.widget
+
+import android.animation.ObjectAnimator
+import android.content.Context
+import android.net.Uri
+import android.util.AttributeSet
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewTreeObserver
+import android.view.animation.DecelerateInterpolator
+import android.widget.RelativeLayout
+import androidx.core.view.isVisible
+import com.android.intentresolver.R
+import kotlinx.coroutines.Job
+import kotlinx.coroutines.MainScope
+import kotlinx.coroutines.coroutineScope
+import kotlinx.coroutines.launch
+import java.util.function.Consumer
+import com.android.internal.R as IntR
+
+private const val IMAGE_FADE_IN_MILLIS = 150L
+
+class ChooserImagePreviewView : RelativeLayout, ImagePreviewView {
+
+    constructor(context: Context) : this(context, null)
+    constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)
+
+    constructor(
+        context: Context, attrs: AttributeSet?, defStyleAttr: Int
+    ) : this(context, attrs, defStyleAttr, 0)
+
+    constructor(
+        context: Context, attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int
+    ) : super(context, attrs, defStyleAttr, defStyleRes)
+
+    private val coroutineScope = MainScope()
+    private lateinit var mainImage: RoundedRectImageView
+    private lateinit var secondLargeImage: RoundedRectImageView
+    private lateinit var secondSmallImage: RoundedRectImageView
+    private lateinit var thirdImage: RoundedRectImageView
+
+    private var loadImageJob: Job? = null
+    private var onTransitionViewReadyCallback: Consumer<Boolean>? = null
+
+    override fun onFinishInflate() {
+        LayoutInflater.from(context).inflate(R.layout.image_preview_view, this, true)
+        mainImage = requireViewById(IntR.id.content_preview_image_1_large)
+        secondLargeImage = requireViewById(IntR.id.content_preview_image_2_large)
+        secondSmallImage = requireViewById(IntR.id.content_preview_image_2_small)
+        thirdImage = requireViewById(IntR.id.content_preview_image_3_small)
+    }
+
+    /**
+     * Specifies a transition animation target name and a readiness callback. The callback will be
+     * invoked once when the view preparation is done i.e. either when an image is loaded into it
+     * and it is laid out (and it is ready to be draw) or image loading has failed.
+     * Should be called before [setImages].
+     * @param name, transition name
+     * @param onViewReady, a callback that will be invoked with `true` if the view is ready to
+     * receive transition animation (the image was loaded successfully) and with `false` otherwise.
+     */
+    override fun setSharedElementTransitionTarget(name: String, onViewReady: Consumer<Boolean>) {
+        mainImage.transitionName = name
+        onTransitionViewReadyCallback = onViewReady
+    }
+
+    override fun setImages(uris: List<Uri>, imageLoader: ImageLoader) {
+        loadImageJob?.cancel()
+        loadImageJob = coroutineScope.launch {
+            when (uris.size) {
+                0 -> hideAllViews()
+                1 -> showOneImage(uris, imageLoader)
+                2 -> showTwoImages(uris, imageLoader)
+                else -> showThreeImages(uris, imageLoader)
+            }
+        }
+    }
+
+    private fun hideAllViews() {
+        mainImage.isVisible = false
+        secondLargeImage.isVisible = false
+        secondSmallImage.isVisible = false
+        thirdImage.isVisible = false
+        invokeTransitionViewReadyCallback(runTransitionAnimation = false)
+    }
+
+    private suspend fun showOneImage(uris: List<Uri>, imageLoader: ImageLoader) {
+        secondLargeImage.isVisible = false
+        secondSmallImage.isVisible = false
+        thirdImage.isVisible = false
+        showImages(uris, imageLoader, mainImage)
+    }
+
+    private suspend fun showTwoImages(uris: List<Uri>, imageLoader: ImageLoader) {
+        secondSmallImage.isVisible = false
+        thirdImage.isVisible = false
+        showImages(uris, imageLoader, mainImage, secondLargeImage)
+    }
+
+    private suspend fun showThreeImages(uris: List<Uri>, imageLoader: ImageLoader) {
+        secondLargeImage.isVisible = false
+        showImages(uris, imageLoader, mainImage, secondSmallImage, thirdImage)
+        thirdImage.setExtraImageCount(uris.size - 3)
+    }
+
+    private suspend fun showImages(
+        uris: List<Uri>, imageLoader: ImageLoader, vararg views: RoundedRectImageView
+    ) = coroutineScope {
+        for (i in views.indices) {
+            launch {
+                loadImageIntoView(views[i], uris[i], imageLoader)
+            }
+        }
+    }
+
+    private suspend fun loadImageIntoView(
+        view: RoundedRectImageView, uri: Uri, imageLoader: ImageLoader
+    ) {
+        val bitmap = runCatching {
+            imageLoader(uri)
+        }.getOrDefault(null)
+        if (bitmap == null) {
+            view.isVisible = false
+            if (view === mainImage) {
+                invokeTransitionViewReadyCallback(runTransitionAnimation = false)
+            }
+        } else {
+            view.isVisible = true
+            view.setImageBitmap(bitmap)
+
+            view.alpha = 0f
+            ObjectAnimator.ofFloat(view, "alpha", 0.0f, 1.0f).apply {
+                interpolator = DecelerateInterpolator(1.0f)
+                duration = IMAGE_FADE_IN_MILLIS
+                start()
+            }
+            if (view === mainImage && onTransitionViewReadyCallback != null) {
+                setupPreDrawListener(mainImage)
+            }
+        }
+    }
+
+    private fun setupPreDrawListener(view: View) {
+        view.viewTreeObserver.addOnPreDrawListener(
+            object : ViewTreeObserver.OnPreDrawListener {
+                override fun onPreDraw(): Boolean {
+                    view.viewTreeObserver.removeOnPreDrawListener(this)
+                    invokeTransitionViewReadyCallback(runTransitionAnimation = true)
+                    return true
+                }
+            }
+        )
+    }
+
+    private fun invokeTransitionViewReadyCallback(runTransitionAnimation: Boolean) {
+        onTransitionViewReadyCallback?.accept(runTransitionAnimation)
+        onTransitionViewReadyCallback = null
+    }
+}
diff --git a/java/src/com/android/intentresolver/widget/ImagePreviewView.kt b/java/src/com/android/intentresolver/widget/ImagePreviewView.kt
index c61c7c72..a5756054 100644
--- a/java/src/com/android/intentresolver/widget/ImagePreviewView.kt
+++ b/java/src/com/android/intentresolver/widget/ImagePreviewView.kt
@@ -16,58 +16,13 @@
 
 package com.android.intentresolver.widget
 
-import android.animation.ObjectAnimator
-import android.content.Context
 import android.graphics.Bitmap
 import android.net.Uri
-import android.util.AttributeSet
-import android.view.LayoutInflater
-import android.view.View
-import android.view.ViewTreeObserver
-import android.view.animation.DecelerateInterpolator
-import android.widget.RelativeLayout
-import androidx.core.view.isVisible
-import com.android.intentresolver.R
-import kotlinx.coroutines.Job
-import kotlinx.coroutines.MainScope
-import kotlinx.coroutines.coroutineScope
-import kotlinx.coroutines.launch
 import java.util.function.Consumer
-import com.android.internal.R as IntR
 
-private typealias ImageLoader = suspend (Uri) -> Bitmap?
+internal typealias ImageLoader = suspend (Uri) -> Bitmap?
 
-private const val IMAGE_FADE_IN_MILLIS = 150L
-
-class ImagePreviewView : RelativeLayout {
-
-    constructor(context: Context) : this(context, null)
-    constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)
-
-    constructor(
-        context: Context, attrs: AttributeSet?, defStyleAttr: Int
-    ) : this(context, attrs, defStyleAttr, 0)
-
-    constructor(
-        context: Context, attrs: AttributeSet?, defStyleAttr: Int, defStyleRes: Int
-    ) : super(context, attrs, defStyleAttr, defStyleRes)
-
-    private val coroutineScope = MainScope()
-    private lateinit var mainImage: RoundedRectImageView
-    private lateinit var secondLargeImage: RoundedRectImageView
-    private lateinit var secondSmallImage: RoundedRectImageView
-    private lateinit var thirdImage: RoundedRectImageView
-
-    private var loadImageJob: Job? = null
-    private var onTransitionViewReadyCallback: Consumer<Boolean>? = null
-
-    override fun onFinishInflate() {
-        LayoutInflater.from(context).inflate(R.layout.image_preview_view, this, true)
-        mainImage = requireViewById(IntR.id.content_preview_image_1_large)
-        secondLargeImage = requireViewById(IntR.id.content_preview_image_2_large)
-        secondSmallImage = requireViewById(IntR.id.content_preview_image_2_small)
-        thirdImage = requireViewById(IntR.id.content_preview_image_3_small)
-    }
+interface ImagePreviewView {
 
     /**
      * Specifies a transition animation target name and a readiness callback. The callback will be
@@ -78,101 +33,7 @@ class ImagePreviewView : RelativeLayout {
      * @param onViewReady, a callback that will be invoked with `true` if the view is ready to
      * receive transition animation (the image was loaded successfully) and with `false` otherwise.
      */
-    fun setSharedElementTransitionTarget(name: String, onViewReady: Consumer<Boolean>) {
-        mainImage.transitionName = name
-        onTransitionViewReadyCallback = onViewReady
-    }
-
-    fun setImages(uris: List<Uri>, imageLoader: ImageLoader) {
-        loadImageJob?.cancel()
-        loadImageJob = coroutineScope.launch {
-            when (uris.size) {
-                0 -> hideAllViews()
-                1 -> showOneImage(uris, imageLoader)
-                2 -> showTwoImages(uris, imageLoader)
-                else -> showThreeImages(uris, imageLoader)
-            }
-        }
-    }
-
-    private fun hideAllViews() {
-        mainImage.isVisible = false
-        secondLargeImage.isVisible = false
-        secondSmallImage.isVisible = false
-        thirdImage.isVisible = false
-        invokeTransitionViewReadyCallback(runTransitionAnimation = false)
-    }
-
-    private suspend fun showOneImage(uris: List<Uri>, imageLoader: ImageLoader) {
-        secondLargeImage.isVisible = false
-        secondSmallImage.isVisible = false
-        thirdImage.isVisible = false
-        showImages(uris, imageLoader, mainImage)
-    }
-
-    private suspend fun showTwoImages(uris: List<Uri>, imageLoader: ImageLoader) {
-        secondSmallImage.isVisible = false
-        thirdImage.isVisible = false
-        showImages(uris, imageLoader, mainImage, secondLargeImage)
-    }
-
-    private suspend fun showThreeImages(uris: List<Uri>, imageLoader: ImageLoader) {
-        secondLargeImage.isVisible = false
-        showImages(uris, imageLoader, mainImage, secondSmallImage, thirdImage)
-        thirdImage.setExtraImageCount(uris.size - 3)
-    }
-
-    private suspend fun showImages(
-        uris: List<Uri>, imageLoader: ImageLoader, vararg views: RoundedRectImageView
-    ) = coroutineScope {
-        for (i in views.indices) {
-            launch {
-                loadImageIntoView(views[i], uris[i], imageLoader)
-            }
-        }
-    }
-
-    private suspend fun loadImageIntoView(
-        view: RoundedRectImageView, uri: Uri, imageLoader: ImageLoader
-    ) {
-        val bitmap = runCatching {
-            imageLoader(uri)
-        }.getOrDefault(null)
-        if (bitmap == null) {
-            view.isVisible = false
-            if (view === mainImage) {
-                invokeTransitionViewReadyCallback(runTransitionAnimation = false)
-            }
-        } else {
-            view.isVisible = true
-            view.setImageBitmap(bitmap)
-
-            view.alpha = 0f
-            ObjectAnimator.ofFloat(view, "alpha", 0.0f, 1.0f).apply {
-                interpolator = DecelerateInterpolator(1.0f)
-                duration = IMAGE_FADE_IN_MILLIS
-                start()
-            }
-            if (view === mainImage && onTransitionViewReadyCallback != null) {
-                setupPreDrawListener(mainImage)
-            }
-        }
-    }
-
-    private fun setupPreDrawListener(view: View) {
-        view.viewTreeObserver.addOnPreDrawListener(
-            object : ViewTreeObserver.OnPreDrawListener {
-                override fun onPreDraw(): Boolean {
-                    view.viewTreeObserver.removeOnPreDrawListener(this)
-                    invokeTransitionViewReadyCallback(runTransitionAnimation = true)
-                    return true
-                }
-            }
-        )
-    }
+    fun setSharedElementTransitionTarget(name: String, onViewReady: Consumer<Boolean>)
 
-    private fun invokeTransitionViewReadyCallback(runTransitionAnimation: Boolean) {
-        onTransitionViewReadyCallback?.accept(runTransitionAnimation)
-        onTransitionViewReadyCallback = null
-    }
+    fun setImages(uris: List<Uri>, imageLoader: ImageLoader)
 }