feat: implement horizontal candidate layout styles with flexible widt…

app/src/main/java/com/osfans/trime/data/prefs/AppPrefs.kt

@@ -10,6 +10,7 @@ import android.content.SharedPreferences
 import androidx.annotation.Keep
 import com.osfans.trime.R
 import com.osfans.trime.data.base.DataManager
+import com.osfans.trime.ime.candidates.compact.HorizontalCandidateMode
 import com.osfans.trime.ime.candidates.popup.PopupCandidatesLayout
 import com.osfans.trime.ime.candidates.popup.PopupCandidatesMode
 import com.osfans.trime.ime.composition.PopupPosition
@@ -152,6 +153,9 @@ class AppPrefs(
             const val HOOK_SHIFT_NUM = "hook_shift_num"
             const val HOOK_SHIFT_SYMBOL = "hook_shift_symbol"
             const val HOOK_SHIFT_ARROW = "hook_shift_arrow"
+
+            const val MAX_SPAN_COUNT = "max_span_count"
+            const val MAX_SPAN_COUNT_LANDSCAPE = "max_span_count_landscape"
         }
 
         enum class LandscapeMode(override val stringRes: Int) : PreferenceDelegateEnum {
@@ -292,6 +296,32 @@ class AppPrefs(
             "dp",
         )
 
+        val horizontalCandidateMode = enum(R.string.horizontal_candidate_style, Candidates.HORIZONTAL_CANDIDATE_MODE, HorizontalCandidateMode.AUTO_FILL)
+
+        val maxSpanCount = int(
+            R.string.max_span_count,
+            MAX_SPAN_COUNT,
+            6,
+            1,
+            10,
+            enableUiOn = {
+                shared.getString(Candidates.HORIZONTAL_CANDIDATE_MODE, null) ==
+                    HorizontalCandidateMode.AUTO_FILL.name
+            },
+        )
+
+        val maxSpanCountLandscape = int(
+            R.string.max_span_count_landscape,
+            MAX_SPAN_COUNT_LANDSCAPE,
+            8,
+            4,
+            12,
+            enableUiOn = {
+                shared.getString(Candidates.HORIZONTAL_CANDIDATE_MODE, null) ==
+                    HorizontalCandidateMode.AUTO_FILL.name
+            },
+        )
+
         val hookCtrlA = switch(R.string.hook_ctrl_a, HOOK_CTRL_A, false)
         val hookCtrlCV = switch(R.string.hook_ctrl_cv, HOOK_CTRL_CV, false)
         val hookCtrlLR = switch(R.string.hook_ctrl_lr, HOOK_CTRL_LR, false)
@@ -309,6 +339,7 @@ class AppPrefs(
             const val MODE = "show_candidates_window"
             const val LAYOUT = "candidates_layout"
             const val POSITION = "candidates_window_position"
+            const val HORIZONTAL_CANDIDATE_MODE = "horizontal_candidate_mode"
         }
 
         val mode = enum(R.string.show_candidates_window, MODE, PopupCandidatesMode.DISABLED)

app/src/main/java/com/osfans/trime/ime/candidates/compact/CompactCandidateModule.kt

@@ -6,20 +6,23 @@
 package com.osfans.trime.ime.candidates.compact
 
 import android.content.Context
+import android.content.res.Configuration
 import android.graphics.drawable.ShapeDrawable
 import android.graphics.drawable.shapes.RectShape
 import android.view.View
 import android.widget.PopupMenu
 import androidx.core.text.bold
 import androidx.core.text.buildSpannedString
 import androidx.core.text.color
+import androidx.core.view.updateLayoutParams
 import androidx.lifecycle.lifecycleScope
 import androidx.recyclerview.widget.RecyclerView
 import com.google.android.flexbox.FlexboxLayoutManager
 import com.osfans.trime.R
 import com.osfans.trime.core.RimeMessage
 import com.osfans.trime.daemon.RimeSession
 import com.osfans.trime.daemon.launchOnReady
+import com.osfans.trime.data.prefs.AppPrefs
 import com.osfans.trime.data.theme.ColorManager
 import com.osfans.trime.data.theme.Theme
 import com.osfans.trime.ime.bar.QuickBar
@@ -47,6 +50,30 @@ class CompactCandidateModule(
     val theme: Theme,
     val bar: QuickBar,
 ) : InputBroadcastReceiver {
+    private val fillStyle by AppPrefs.defaultInstance().keyboard.horizontalCandidateMode
+
+    private val maxSpanCountPref by lazy {
+        AppPrefs.defaultInstance().keyboard.run {
+            if (context.resources.configuration.orientation == Configuration.ORIENTATION_PORTRAIT) {
+                maxSpanCount
+            } else {
+                maxSpanCountLandscape
+            }
+        }
+    }
+
+    private var layoutMinWidth = 0
+    private var layoutFlexGrow = 0f
+
+    /**
+     * (for [HorizontalCandidateMode.AutoFill] only)
+     * Second layout pass is needed when:
+     * [^1] total candidates count < maxSpanCount && [^2] RecyclerView cannot display all of them
+     * In that case, displayed candidates should be stretched evenly (by setting flexGrow to 1.0f).
+     */
+    private var secondLayoutPassNeeded = false
+    private var secondLayoutPassDone = false
+
     private val _unrolledCandidateOffset =
         MutableSharedFlow<Int>(
             replay = 1,
@@ -81,6 +108,11 @@ class CompactCandidateModule(
         }
     }
 
+    fun updateLayoutParams(minWidth: Int, flexGrow: Float) {
+        layoutMinWidth = minWidth
+        layoutFlexGrow = flexGrow
+    }
+
     val layoutManager by lazy {
         object : FlexboxLayoutManager(context) {
             override fun canScrollHorizontally(): Boolean = false
@@ -89,7 +121,24 @@ class CompactCandidateModule(
 
             override fun onLayoutCompleted(state: RecyclerView.State?) {
                 super.onLayoutCompleted(state)
-                refreshUnrolled(this.childCount)
+                val cnt = this.childCount
+                if (secondLayoutPassNeeded) {
+                    if (cnt < adapter.itemCount) {
+                        // [^2] RecyclerView can't display all candidates
+                        // update LayoutParams in onLayoutCompleted would trigger another
+                        // onLayoutCompleted, skip the second one to avoid infinite loop
+                        if (secondLayoutPassDone) return
+                        secondLayoutPassDone = true
+                        for (i in 0 until cnt) {
+                            getChildAt(i)!!.updateLayoutParams<LayoutParams> {
+                                flexGrow = 1f
+                            }
+                        }
+                    } else {
+                        secondLayoutPassNeeded = false
+                    }
+                }
+                refreshUnrolled(cnt)
             }
         }
     }
@@ -113,9 +162,59 @@ class CompactCandidateModule(
         }
     }
 
+    init {
+        // Update layoutMinWidth when view size changes
+        view.addOnLayoutChangeListener(
+            object : View.OnLayoutChangeListener {
+                override fun onLayoutChange(
+                    v: View,
+                    left: Int,
+                    top: Int,
+                    right: Int,
+                    bottom: Int,
+                    oldLeft: Int,
+                    oldTop: Int,
+                    oldRight: Int,
+                    oldBottom: Int,
+                ) {
+                    if (fillStyle == HorizontalCandidateMode.AUTO_FILL) {
+                        val maxSpanCount = maxSpanCountPref.getValue()
+                        layoutMinWidth = v.width / maxSpanCount - separatorDrawable.intrinsicWidth
+                    }
+                }
+            },
+        )
+    }
+
     override fun onCandidateListUpdate(data: RimeMessage.CandidateListMessage.Data) {
         val (total, highlighted, candidates) = data
+
+        val maxSpanCount = maxSpanCountPref.getValue()
+
+        when (fillStyle) {
+            HorizontalCandidateMode.NEVER_FILL -> {
+                layoutMinWidth = 0
+                layoutFlexGrow = 0f
+                secondLayoutPassNeeded = false
+            }
+            HorizontalCandidateMode.AUTO_FILL -> {
+                layoutMinWidth = view.width / maxSpanCount - separatorDrawable.intrinsicWidth
+                layoutFlexGrow = if (candidates.size < maxSpanCount) 0f else 1f
+                // [^1] total candidates count < maxSpanCount
+                secondLayoutPassNeeded = candidates.size < maxSpanCount
+                secondLayoutPassDone = false
+            }
+            HorizontalCandidateMode.ALWAYS_FILL -> {
+                layoutMinWidth = 0
+                layoutFlexGrow = 1f
+                secondLayoutPassNeeded = false
+            }
+        }
+
+        adapter.updateLayoutParams(layoutMinWidth, layoutFlexGrow)
         adapter.updateCandidates(candidates, total, highlighted)
+
+        // not sure why empty candidates won't trigger `FlexboxLayoutManager#onLayoutCompleted()`
         if (candidates.isEmpty()) {
             refreshUnrolled(0)
         }

app/src/main/java/com/osfans/trime/ime/candidates/compact/CompactCandidateViewAdapter.kt

@@ -34,6 +34,17 @@ open class CompactCandidateViewAdapter(
     var highlightedIdx: Int = -1
         private set
 
+    var layoutMinWidth: Int = 0
+        private set
+
+    var layoutFlexGrow: Float = 0f
+        private set
+
+    fun updateLayoutParams(minWidth: Int, flexGrow: Float) {
+        layoutMinWidth = minWidth
+        layoutFlexGrow = flexGrow
+    }
+
     fun updateCandidates(
         data: Array<CandidateItem>,
         total: Int,
@@ -71,8 +82,8 @@ open class CompactCandidateViewAdapter(
         holder.comment = item.comment
         holder.idx = position // unused
         holder.ui.root.updateLayoutParams<FlexboxLayoutManager.LayoutParams> {
-            minWidth = 0
-            flexGrow = 0f
+            minWidth = this@CompactCandidateViewAdapter.layoutMinWidth
+            flexGrow = this@CompactCandidateViewAdapter.layoutFlexGrow
         }
     }
 }

app/src/main/java/com/osfans/trime/ime/candidates/compact/HorizontalCandidateMode.kt

@@ -0,0 +1,17 @@
+/*
+ * SPDX-FileCopyrightText: 2015 - 2025 Rime community
+ * SPDX-License-Identifier: GPL-3.0-or-later
+ */
+
+package com.osfans.trime.ime.candidates.compact
+
+import com.osfans.trime.R
+import com.osfans.trime.data.prefs.PreferenceDelegateEnum
+
+enum class HorizontalCandidateMode(
+    override val stringRes: Int,
+) : PreferenceDelegateEnum {
+    NEVER_FILL(R.string.horizontal_candidate_never_fill),
+    AUTO_FILL(R.string.horizontal_candidate_auto_fill),
+    ALWAYS_FILL(R.string.horizontal_candidate_always_fill),
+}

app/src/main/res/values-zh-rCN/strings.xml

@@ -187,6 +187,12 @@
     <string name="ascii_switch_tips">切换中英文模式时显示提示</string>
     <string name="key_double_tap_timeout">按键双击超时</string>
     <string name="key_slide_step_size">按键滑动步长</string>
+    <string name="horizontal_candidate_style">横向候选词样式</string>
+    <string name="horizontal_candidate_never_fill">从不填充宽度</string>
+    <string name="horizontal_candidate_auto_fill">按需填充宽度</string>
+    <string name="horizontal_candidate_always_fill">总是填充宽度</string>
+    <string name="max_span_count">每行最大候选词数</string>
+    <string name="max_span_count_landscape">每行最大候选词数(横屏)</string>
     <string name="user_dictionary">用户词典</string>
     <string name="exported_n_entries">已导出 %1$d 个词条</string>
     <string name="backed_up_x_to_sync_dir">已备份 %1$s 到同步目录</string>

app/src/main/res/values-zh-rTW/strings.xml

@@ -188,6 +188,12 @@
     <string name="ascii_switch_tips">切換中英文模式時顯示提示</string>
     <string name="key_double_tap_timeout">按鍵連擊逾時</string>
     <string name="key_slide_step_size">按鍵滑動步長</string>
+    <string name="horizontal_candidate_style">橫向候選詞樣式</string>
+    <string name="horizontal_candidate_never_fill">從不填充寬度</string>
+    <string name="horizontal_candidate_auto_fill">按需填充寬度</string>
+    <string name="horizontal_candidate_always_fill">總是填充寬度</string>
+    <string name="max_span_count">每行最大候選詞數</string>
+    <string name="max_span_count_landscape">每行最大候選詞數(橫屏)</string>
     <string name="user_dictionary">使用者詞典</string>
     <string name="exported_n_entries">已匯出 %1$d 個詞條</string>
     <string name="backed_up_x_to_sync_dir">已備份 %1$s 到同步目錄</string>

app/src/main/res/values/strings.xml

@@ -188,6 +188,12 @@
     <string name="ascii_switch_tips">Show tips when switching ASCII mode</string>
     <string name="key_double_tap_timeout">Key double tap timeout</string>
     <string name="key_slide_step_size">Step size for key sliding</string>
+    <string name="horizontal_candidate_style">Horizontal candidate style</string>
+    <string name="horizontal_candidate_never_fill">Never fill width</string>
+    <string name="horizontal_candidate_auto_fill">Fill width on demand</string>
+    <string name="horizontal_candidate_always_fill">Always fill width</string>
+    <string name="max_span_count">Maximum candidates per row</string>
+    <string name="max_span_count_landscape">Maximum candidates per row (landscape)</string>
     <string name="user_dictionary">User dictionary</string>
     <string name="import_">Import</string>
     <string name="import_error">Import error</string>