feat: add PageinationUi to indicate if candidates page has prev or next

app/src/main/java/com/osfans/trime/ime/candidates/popup/PagedCandidatesUi.kt

@@ -8,6 +8,7 @@ package com.osfans.trime.ime.candidates.popup
 import android.content.Context
 import android.view.View
 import android.view.ViewGroup
+import androidx.core.view.updateLayoutParams
 import androidx.recyclerview.widget.RecyclerView
 import com.chad.library.adapter4.BaseQuickAdapter
 import com.google.android.flexbox.AlignItems
@@ -25,12 +26,20 @@ class PagedCandidatesUi(
 ) : Ui {
     private var menu = RimeProto.Context.Menu()
 
-    class UiViewHolder(
-        val ui: Ui,
-    ) : RecyclerView.ViewHolder(ui.root)
+    sealed class UiHolder(
+        open val ui: Ui,
+    ) : RecyclerView.ViewHolder(ui.root) {
+        class Candidate(
+            override val ui: LabeledCandidateItemUi,
+        ) : UiHolder(ui)
+
+        class Pagination(
+            override val ui: PaginationUi,
+        ) : UiHolder(ui)
+    }
 
     val candidatesAdapter =
-        object : BaseQuickAdapter<RimeProto.Candidate, UiViewHolder>() {
+        object : BaseQuickAdapter<RimeProto.Candidate, UiHolder>() {
             override fun getItemCount(items: List<RimeProto.Candidate>) =
                 items.size + (if (menu.pageNumber != 0 || !menu.isLastPage) 1 else 0)
 
@@ -43,23 +52,35 @@ class PagedCandidatesUi(
                 context: Context,
                 parent: ViewGroup,
                 viewType: Int,
-            ): UiViewHolder =
+            ): UiHolder =
                 when (viewType) {
-                    0 -> UiViewHolder(LabeledCandidateItemUi(ctx, theme))
-                    else -> UiViewHolder(LabeledCandidateItemUi(ctx, theme))
+                    0 -> UiHolder.Candidate(LabeledCandidateItemUi(ctx, theme))
+                    else ->
+                        UiHolder.Pagination(PaginationUi(ctx, theme)).apply {
+                            val wrap = ViewGroup.LayoutParams.WRAP_CONTENT
+                            ui.root.layoutParams =
+                                FlexboxLayoutManager.LayoutParams(wrap, wrap).apply {
+                                    flexGrow = 1f
+                                }
+                        }
                 }
 
             override fun onBindViewHolder(
-                holder: UiViewHolder,
+                holder: UiHolder,
                 position: Int,
                 item: RimeProto.Candidate?,
             ) {
-                when (getItemViewType(position)) {
-                    0 -> {
-                        holder.ui as LabeledCandidateItemUi
+                when (holder) {
+                    is UiHolder.Candidate -> {
                         val candidate = item ?: return
                         holder.ui.update(candidate, position == menu.highlightedCandidateIndex)
                     }
+                    is UiHolder.Pagination -> {
+                        holder.ui.update(menu)
+                        holder.ui.root.updateLayoutParams<FlexboxLayoutManager.LayoutParams> {
+                            alignSelf = AlignItems.CENTER
+                        }
+                    }
                 }
             }
         }.apply {

app/src/main/java/com/osfans/trime/ime/candidates/popup/PaginationUi.kt

@@ -0,0 +1,70 @@
+/*
+ * SPDX-FileCopyrightText: 2015 - 2024 Rime community
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package com.osfans.trime.ime.candidates.popup
+
+import android.content.Context
+import android.content.res.ColorStateList
+import android.widget.ImageView
+import androidx.annotation.DrawableRes
+import com.osfans.trime.R
+import com.osfans.trime.core.RimeProto
+import com.osfans.trime.data.theme.ColorManager
+import com.osfans.trime.data.theme.Theme
+import com.osfans.trime.util.styledFloat
+import splitties.dimensions.dp
+import splitties.resources.drawable
+import splitties.views.dsl.constraintlayout.before
+import splitties.views.dsl.constraintlayout.centerVertically
+import splitties.views.dsl.constraintlayout.constraintLayout
+import splitties.views.dsl.constraintlayout.endOfParent
+import splitties.views.dsl.constraintlayout.lParams
+import splitties.views.dsl.core.Ui
+import splitties.views.dsl.core.add
+import splitties.views.dsl.core.imageView
+import splitties.views.imageDrawable
+
+class PaginationUi(
+    override val ctx: Context,
+    val theme: Theme,
+) : Ui {
+    private fun createIcon(
+        @DrawableRes icon: Int,
+    ) = imageView {
+        imageTintList = ColorStateList.valueOf(ColorManager.getColor("key_text_color")!!)
+        imageDrawable = drawable(icon)
+        scaleType = ImageView.ScaleType.CENTER_CROP
+    }
+
+    private val prevIcon = createIcon(R.drawable.ic_baseline_arrow_left_24)
+    private val nextIcon = createIcon(R.drawable.ic_baseline_arrow_right_24)
+
+    private val disabledAlpha = ctx.styledFloat(android.R.attr.disabledAlpha)
+
+    override val root =
+        constraintLayout {
+            val w = dp(10)
+            val h = dp(20)
+            add(
+                nextIcon,
+                lParams(w, h) {
+                    centerVertically()
+                    endOfParent()
+                },
+            )
+            add(
+                prevIcon,
+                lParams(w, h) {
+                    centerVertically()
+                    before(nextIcon)
+                },
+            )
+        }
+
+    fun update(menu: RimeProto.Context.Menu) {
+        prevIcon.alpha = if (menu.pageNumber != 0) 1f else disabledAlpha
+        nextIcon.alpha = if (!menu.isLastPage) 1f else disabledAlpha
+    }
+}

app/src/main/java/com/osfans/trime/ime/candidates/unrolled/window/BaseUnrolledCandidateWindow.kt

@@ -24,8 +24,8 @@ import com.osfans.trime.ime.bar.UnrollButtonStateMachine
 import com.osfans.trime.ime.broadcast.InputBroadcastReceiver
 import com.osfans.trime.ime.candidates.CandidateViewHolder
 import com.osfans.trime.ime.candidates.compact.CompactCandidateModule
-import com.osfans.trime.ime.candidates.unrolled.PagingCandidateViewAdapter
 import com.osfans.trime.ime.candidates.unrolled.CandidatesPagingSource
+import com.osfans.trime.ime.candidates.unrolled.PagingCandidateViewAdapter
 import com.osfans.trime.ime.candidates.unrolled.UnrolledCandidateLayout
 import com.osfans.trime.ime.core.TrimeInputMethodService
 import com.osfans.trime.ime.keyboard.KeyboardSwitcher

app/src/main/res/drawable/ic_baseline_arrow_left_24.xml

@@ -0,0 +1,5 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android" android:autoMirrored="true" android:height="24dp" android:tint="#000000" android:viewportHeight="24" android:viewportWidth="24" android:width="24dp">
+
+    <path android:fillColor="@android:color/white" android:pathData="M14,7l-5,5 5,5V7z"/>
+
+</vector>

app/src/main/res/drawable/ic_baseline_arrow_right_24.xml

@@ -0,0 +1,5 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android" android:autoMirrored="true" android:height="24dp" android:tint="#000000" android:viewportHeight="24" android:viewportWidth="24" android:width="24dp">
+
+    <path android:fillColor="@android:color/white" android:pathData="M10,17l5,-5 -5,-5v10z"/>
+
+</vector>