A base scrollable action row implementation

A base implementation of the new scrollable action row; the view is
added to the codebase but not used.

Bug: 262278109
Test: Tested with some debug code injections (base functionality, a11y,
unit tests).

Change-Id: Ic109440ce9609e73b72fc86c2cd455c42a421103

1 files changed, 120 insertions, 0 deletions

diff --git a/java/src/com/android/intentresolver/widget/ScrollableActionRow.kt b/java/src/com/android/intentresolver/widget/ScrollableActionRow.kt
new file mode 100644
index 00000000..f3a34985
--- /dev/null
+++ b/java/src/com/android/intentresolver/widget/ScrollableActionRow.kt
@@ -0,0 +1,120 @@
+/*
+ * 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.content.Context
+import android.util.AttributeSet
+import android.view.LayoutInflater
+import android.view.View
+import android.view.ViewGroup
+import android.widget.TextView
+import androidx.recyclerview.widget.LinearLayoutManager
+import androidx.recyclerview.widget.RecyclerView
+import com.android.intentresolver.R
+
+class ScrollableActionRow : RecyclerView, ActionRow {
+    constructor(context: Context) : this(context, null)
+    constructor(context: Context, attrs: AttributeSet?) : this(context, attrs, 0)
+    constructor(
+        context: Context, attrs: AttributeSet?, defStyleAttr: Int
+    ) : super(context, attrs, defStyleAttr) {
+        layoutManager = LinearLayoutManager(context, LinearLayoutManager.HORIZONTAL, false)
+        adapter = Adapter(context)
+    }
+
+    private val actionsAdapter get() = adapter as Adapter
+
+    override fun setActions(actions: List<ActionRow.Action>) {
+        actionsAdapter.setActions(actions)
+    }
+
+    override fun onLayout(changed: Boolean, l: Int, t: Int, r: Int, b: Int) {
+        super.onLayout(changed, l, t, r, b)
+        setOverScrollMode(
+            if (areAllChildrenVisible) View.OVER_SCROLL_NEVER else View.OVER_SCROLL_ALWAYS
+        )
+    }
+
+    private val areAllChildrenVisible: Boolean
+        get() {
+            val count = getChildCount()
+            if (count == 0) return true
+            val first = getChildAt(0)
+            val last = getChildAt(count - 1)
+            return getChildAdapterPosition(first) == 0
+                && getChildAdapterPosition(last) == actionsAdapter.itemCount - 1
+                && isFullyVisible(first)
+                && isFullyVisible(last)
+        }
+
+    private fun isFullyVisible(view: View): Boolean =
+        view.left >= paddingLeft && view.right <= width - paddingRight
+
+    private class Adapter(private val context: Context) : RecyclerView.Adapter<ViewHolder>() {
+        private val iconSize: Int =
+            context.resources.getDimensionPixelSize(R.dimen.chooser_action_view_icon_size)
+        private val itemLayout = R.layout.chooser_action_view
+        private var actions: List<ActionRow.Action> = emptyList()
+
+        override fun onCreateViewHolder(parent: ViewGroup, type: Int): ViewHolder =
+            ViewHolder(
+                LayoutInflater.from(context).inflate(itemLayout, null) as TextView,
+                iconSize
+            )
+
+        override fun onBindViewHolder(holder: ViewHolder, position: Int) {
+            holder.bind(actions[position])
+        }
+
+        override fun getItemCount() = actions.size
+
+        override fun onViewRecycled(holder: ViewHolder) {
+            holder.unbind()
+        }
+
+        override fun onFailedToRecycleView(holder: ViewHolder): Boolean {
+            holder.unbind()
+            return super.onFailedToRecycleView(holder)
+        }
+
+        fun setActions(actions: List<ActionRow.Action>) {
+            this.actions = ArrayList(actions)
+            notifyDataSetChanged()
+        }
+    }
+
+    private class ViewHolder(
+        private val view: TextView, private val iconSize: Int
+    ) : RecyclerView.ViewHolder(view) {
+
+        fun bind(action: ActionRow.Action) {
+            if (action.icon != null) {
+                action.icon.setBounds(0, 0, iconSize, iconSize)
+                view.setCompoundDrawablesRelative(null, action.icon, null, null)
+            }
+            view.text = action.label ?: ""
+            view.setOnClickListener {
+                action.onClicked.run()
+            }
+            view.id = action.id
+        }
+
+        fun unbind() {
+            view.setOnClickListener(null)
+        }
+    }
+}