redesign course page: select course to enter training, guard tabs without course

android/sample-app/src/main/java/cn/learningpad/oraltrainer/sample/MainActivity.kt

@@ -42,6 +42,7 @@ import android.widget.ScrollView
 import android.widget.SeekBar
 import android.widget.Switch
 import android.widget.TextView
+import android.widget.Toast
 import cn.learningpad.oraltrainer.sdk.GestureEvent
 import cn.learningpad.oraltrainer.sdk.GestureKind
 import cn.learningpad.oraltrainer.sdk.AuthSession
@@ -127,6 +128,7 @@ class MainActivity : Activity() {
     private val courseEnrollment = mutableMapOf<String, Boolean>()
     private var catalogStatusTextValue = "正在同步"
     private var activeModule = Module.TRAIN
+    private var currentCourse: TrainingVideoSummary? = null
     private var continuousPlaybackEnabled = false
     private var testSubtitleVisible = false
     private var landscapeSubtitleVisible = true
@@ -550,6 +552,7 @@ class MainActivity : Activity() {
         authToken = ""
         authNickname = ""
         sdk.config.userToken = null
+        currentCourse = null
         controller.pause()
         activeModule = Module.TRAIN
         setRootView()
@@ -615,6 +618,10 @@ class MainActivity : Activity() {
                 if (activeModule == module) {
                     return@setOnClickListener
                 }
+                if (module != Module.COURSE && currentCourse == null) {
+                    Toast.makeText(this@MainActivity, "请先选择课程", Toast.LENGTH_SHORT).show()
+                    return@setOnClickListener
+                }
                 if (module == Module.COURSE || module == Module.MINE) {
                     loadUserData()
                 }
@@ -948,7 +955,7 @@ class MainActivity : Activity() {
             orientation = LinearLayout.HORIZONTAL
             setPadding(0, 10.dp, 0, 4.dp)
         }
-
+        // Fresh instances each time — safe to addView.
         val header = LinearLayout(this).apply {
             orientation = LinearLayout.HORIZONTAL
             gravity = Gravity.CENTER_VERTICAL
@@ -1757,28 +1764,35 @@ class MainActivity : Activity() {
     }
 
     private fun createCourseSection(): View {
-        if (!::catalogList.isInitialized) {
+        catalogStatusText = TextView(this).apply {
+            setTextColor(COLOR_TEXT_MUTED)
+            textSize = 13f
+            text = catalogStatusTextValue
+            setPadding(16.dp, 0.dp, 16.dp, 8.dp)
+        }
         catalogList = LinearLayout(this).apply {
             orientation = LinearLayout.VERTICAL
-            }
+            setPadding(16.dp, 8.dp, 16.dp, 16.dp)
         }
         return ScrollView(this).apply {
             layoutParams = LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, 0, 1f)
             addView(LinearLayout(this@MainActivity).apply {
                 orientation = LinearLayout.VERTICAL
-                setPadding(16.dp, 12.dp, 16.dp, 16.dp)
+                setPadding(0.dp, 12.dp, 0.dp, 16.dp)
                 addView(TextView(this@MainActivity).apply {
                     text = "课程首页"
                     textSize = 26f
                     typeface = Typeface.DEFAULT_BOLD
                     setTextColor(Color.WHITE)
+                    setPadding(16.dp, 0.dp, 16.dp, 0.dp)
                 })
                 addView(TextView(this@MainActivity).apply {
                     text = "选择一门课程开始训练"
                     textSize = 13f
                     setTextColor(COLOR_TEXT_MUTED)
-                    setPadding(0, 4.dp, 0, 16.dp)
+                    setPadding(16.dp, 4.dp, 16.dp, 8.dp)
                 })
+                addView(catalogStatusText)
                 addView(catalogList)
             })
         }
@@ -1818,15 +1832,35 @@ class MainActivity : Activity() {
     private fun refreshMyContent() {
         val list = myContentList ?: return
         list.removeAllViews()
+        val course = currentCourse
+        if (course == null) {
+            list.addView(infoCard("请先在「课程」中选择一门课程"))
+            return
+        }
+        list.addView(TextView(this).apply {
+            text = "当前课程：${course.title}"
+            setTextColor(Color.WHITE)
+            textSize = 14f
+            typeface = Typeface.DEFAULT_BOLD
+            setPadding(0, 0, 0, 8.dp)
+        })
         list.addView(infoCard("加载中..."))
         sdk.userApi.results(authToken) { result ->
             list.removeAllViews()
+            list.addView(TextView(this).apply {
+                text = "当前课程：${course.title}"
+                setTextColor(Color.WHITE)
+                textSize = 14f
+                typeface = Typeface.DEFAULT_BOLD
+                setPadding(0, 0, 0, 8.dp)
+            })
             result.fold(
                 onSuccess = { rows ->
-                    if (rows.isEmpty()) list.addView(infoCard("还没有测试记录"))
-                    rows.forEach { row ->
+                    val filtered = rows.filter { it.videoHash == course.videoHash }
+                    if (filtered.isEmpty()) list.addView(infoCard("该课程还没有测试记录"))
+                    filtered.forEach { row ->
                         list.addView(infoCard(
-                            "${row.courseTitle} · 第 ${row.sentenceIndex + 1} 句\n" +
+                            "第 ${row.sentenceIndex + 1} 句\n" +
                                 "得分 ${row.overallScore.toInt()} · ${if (row.passed) "通过" else "未通过"}"
                         ))
                     }
@@ -1838,10 +1872,11 @@ class MainActivity : Activity() {
                     list.addView(titleDivider("我的配音分享"))
                     shareResult.fold(
                         onSuccess = { shares ->
-                            if (shares.isEmpty()) list.addView(infoCard("还没有分享配音"))
-                            shares.forEach { row ->
+                            val filtered = shares.filter { it.videoHash == course.videoHash }
+                            if (filtered.isEmpty()) list.addView(infoCard("该课程还没有分享配音"))
+                            filtered.forEach { row ->
                                 list.addView(infoCard(
-                                    "${row.title}\n${row.courseTitle} · ${row.segmentCount} 句 · 平均 ${row.averageScore.toInt()} 分"
+                                    "${row.title}\n${row.segmentCount} 句 · 平均 ${row.averageScore.toInt()} 分"
                                 ))
                             }
                         },
@@ -1881,6 +1916,18 @@ class MainActivity : Activity() {
             return
         }
         catalogList.removeAllViews()
+        if (activeModule == Module.COURSE) {
+            if (catalogVideos.isEmpty()) {
+                catalogList.addView(infoCard("暂无课程"))
+                return
+            }
+            catalogVideos.forEach { video ->
+                catalogList.addView(courseListCard(video) {
+                    selectCourse(video)
+                })
+            }
+            return
+        }
         catalogVideos.forEach { video ->
             val enrolled = courseEnrollment[video.videoHash] == true
             catalogList.addView(
@@ -1899,6 +1946,59 @@ class MainActivity : Activity() {
         }
     }
 
+    private fun courseListCard(
+        video: TrainingVideoSummary,
+        onClick: () -> Unit,
+    ): View {
+        val enrolled = courseEnrollment[video.videoHash] == true
+        val isSelected = currentCourse?.videoHash == video.videoHash
+        return LinearLayout(this).apply {
+            orientation = LinearLayout.VERTICAL
+            isClickable = true
+            background = if (isSelected) {
+                rounded(COLOR_SELECTED, 10f, COLOR_ACCENT)
+            } else {
+                rounded(COLOR_SURFACE, 10f, COLOR_BORDER)
+            }
+            setPadding(16.dp, 14.dp, 16.dp, 14.dp)
+            layoutParams = LinearLayout.LayoutParams(
+                ViewGroup.LayoutParams.MATCH_PARENT,
+                ViewGroup.LayoutParams.WRAP_CONTENT,
+            ).withMargins(0, 0, 0, 10.dp)
+            setOnClickListener { onClick() }
+            addView(TextView(this@MainActivity).apply {
+                text = video.title
+                setTextColor(if (isSelected) COLOR_TEXT_DARK else Color.WHITE)
+                textSize = 16f
+                typeface = Typeface.DEFAULT_BOLD
+                maxLines = 2
+            })
+            addView(TextView(this@MainActivity).apply {
+                text = buildString {
+                    append(if (enrolled) "已选修" else "未选修")
+                    append(" · ${video.sentenceCount} 句")
+                    if (isSelected) append(" · 当前课程")
+                }
+                setTextColor(if (isSelected) COLOR_ACCENT_DEEP else COLOR_TEXT_MUTED)
+                textSize = 13f
+                setPadding(0, 6.dp, 0, 0)
+            })
+        }
+    }
+
+    private fun selectCourse(video: TrainingVideoSummary) {
+        currentCourse = video
+        if (courseEnrollment[video.videoHash] != true) {
+            enrollCourse(video)
+        }
+        activeModule = Module.TRAIN
+        landscapeSubtitleVisible = true
+        setContentView(createContentView())
+        renderCatalog()
+        refreshCurrentUi()
+        loadRemoteVideo(video)
+    }
+
     private fun enrollCourse(video: TrainingVideoSummary) {
         sdk.userApi.enroll(authToken, video.videoHash) { result ->
             result.fold(