界面: 歌曲列表行高自适应铺满屏幕(消除投影/高分屏底部空白)

- SongListAdapter: 新增 rowHeightPx/fitRowHeight/rowsPerPage, 分页列表(2列目录5行/排行6行)
  按 ListView 实际可视高度均分行高(clamp 52-160dp), 内容垂直居中, 背景整行铺满
- 滚动型列表(已点/下载/已唱)保持自然行高
- MainActivity.renderSongList: 布局完成后 post fitRowHeight

app/src/main/java/com/local/ktv/MainActivity.kt

@@ -9091,6 +9091,13 @@ class MainActivity : AppCompatActivity() {
         }
         val pageOffset = if (mode == "rank") browsePage * browsePageSize() else 0
         val existing = modernSongAdapter?.takeIf { it.matches(mode, pageOffset) && list.adapter === it }
+        // 分页网格/排行列表: 行高自适应铺满屏幕(2列目录每页5行, 排行单列每页6行);
+        // 可滚动的队列/下载/已唱列表保持自然行高(rowsPerPage=0)。
+        val rowsPerPage = when (mode) {
+            "catalog" -> 5
+            "rank" -> 6
+            else -> 0
+        }
         val listAdapter = existing ?: SongListAdapter(
             this,
             visibleSongs,
@@ -9109,11 +9116,17 @@ class MainActivity : AppCompatActivity() {
                 },
                 onPauseResume = { song -> toggleDownloadPause(song) },
             ),
+            initialRowHeightPx = 0,
+            rowsPerPage = rowsPerPage,
         ).also {
             modernSongAdapter = it
             list.adapter = it
         }
         if (existing != null) listAdapter.notifyDataSetChanged()
+        // 布局完成后按实际可视高度拉满各行, 消除投影/高分屏底部空白。
+        if (rowsPerPage > 0) {
+            list.post { if (list.adapter === listAdapter) listAdapter.fitRowHeight(list.height) }
+        }
 
         val targetPosition = focusedMarker?.let(listAdapter::adapterPositionFor)
             ?: oldSelectedPosition.takeIf { it >= 0 }

app/src/main/java/com/local/ktv/SongListAdapter.kt

@@ -42,11 +42,32 @@ class SongListAdapter(
     private val nextPageFocusId: Int,
     private val stateFor: (Song) -> SongRowState,
     private val callbacks: SongListCallbacks,
+    private val initialRowHeightPx: Int = 0,
+    private val rowsPerPage: Int = 0,
 ) : BaseAdapter() {
     private val density = context.resources.displayMetrics.density
     private val columns = if (mode in SINGLE_COLUMN_MODES) 1 else 2
     private val cardIds = HashMap<String, Int>()
 
+    /** 当前行高(px)。0 = 保持内容自然高度(滚动列表用)。 */
+    var rowHeightPx: Int = initialRowHeightPx
+        private set
+
+    /**
+     * 让行高铺满可用高度: 把列表可视高度按每页行数均分(分页列表专用)。
+     * 超出 min/max 范围时收敛, 避免过小/过大。滚动列表(rowsPerPage<=0)忽略。
+     */
+    fun fitRowHeight(availableHeightPx: Int) {
+        if (rowsPerPage <= 0 || availableHeightPx <= 0) return
+        val minPx = dp(52)
+        val maxPx = dp(160)
+        val fitted = (availableHeightPx / rowsPerPage).coerceIn(minPx, maxPx)
+        if (fitted != rowHeightPx) {
+            rowHeightPx = fitted
+            notifyDataSetChanged()
+        }
+    }
+
     private fun cardId(index: Int): Int = cardIds.getOrPut(songKey(songs[index])) { View.generateViewId() }
 
     override fun getCount(): Int = ceil(songs.size / columns.toDouble()).toInt()
@@ -64,27 +85,34 @@ class SongListAdapter(
     }
 
     override fun getView(position: Int, convertView: View?, parent: ViewGroup): View {
-        if (columns == 1) {
-            return createSingleRow(songs[position], position).apply {
+        val view = if (columns == 1) {
+            createSingleRow(songs[position], position).apply {
                 if (position == count - 1) nextFocusDownId = previousPageFocusId
             }
-        }
-        return LinearLayout(context).apply {
-            orientation = LinearLayout.HORIZONTAL
-            gravity = Gravity.CENTER_VERTICAL
-            val cells = mutableListOf<View>()
-            repeat(2) { column ->
-                val index = position * 2 + column
-                val cell = songs.getOrNull(index)?.let {
-                    createCatalogCell(it, index, column, position == count - 1)
-                } ?: View(context)
-                cells += cell
-                addView(
-                    cell,
-                    LinearLayout.LayoutParams(0, dp(60), 1f),
-                )
+        } else {
+            LinearLayout(context).apply {
+                orientation = LinearLayout.HORIZONTAL
+                gravity = Gravity.CENTER_VERTICAL
+                repeat(2) { column ->
+                    val index = position * 2 + column
+                    val cell = songs.getOrNull(index)?.let {
+                        createCatalogCell(it, index, column, position == count - 1)
+                    } ?: View(context)
+                    addView(
+                        cell,
+                        LinearLayout.LayoutParams(0, -1, 1f),
+                    )
+                }
             }
         }
+        // 分页列表: 让整行背景铺满均分行高; 滚动列表保持自然高度。
+        if (rowHeightPx > 0) {
+            view.layoutParams = android.widget.AbsListView.LayoutParams(
+                android.widget.AbsListView.LayoutParams.MATCH_PARENT,
+                rowHeightPx,
+            )
+        }
+        return view
     }
 
     private fun createSingleRow(song: Song, index: Int): View = when (mode) {