尝试解决二次启动时文件读取问题

android/app/src/main/kotlin/com/lxh/battery_health/MainActivity.kt

@@ -4,6 +4,7 @@ import android.content.BroadcastReceiver
 import android.content.Context
 import android.content.Intent
 import android.content.IntentFilter
+import android.content.SharedPreferences
 import android.net.Uri
 import android.os.BatteryManager
 import android.os.Build
@@ -20,18 +21,17 @@ import java.io.BufferedReader
 import java.io.InputStreamReader
 
 class MainActivity : FlutterActivity() {
-    // ---------- 充电状态 ----------
     private val CHARGE_CHANNEL = "com.lxh.battery_health/charge"
     private val EVENT_CHANNEL = "com.lxh.battery_health/charge_events"
     private var eventSink: EventChannel.EventSink? = null
 
-    // ---------- SAF 相关 ----------
     private val SAF_CHANNEL = "com.lxh.battery_health/saf"
     private var safResult: MethodChannel.Result? = null
     private var safUri: Uri? = null
     private val FOLDER_PICKER_REQUEST = 1001
+    private val PREF_NAME = "battery_health_prefs"
+    private val KEY_SAF_URI = "saf_uri"
 
-    // ---------- 充电广播接收器 ----------
     private val chargeReceiver = object : BroadcastReceiver() {
         override fun onReceive(context: Context?, intent: Intent?) {
             intent ?: return
@@ -42,6 +42,32 @@ class MainActivity : FlutterActivity() {
         }
     }
 
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+
+        // 🟢 从 SharedPreferences 恢复 URI
+        val prefs: SharedPreferences = getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE)
+        val uriString = prefs.getString(KEY_SAF_URI, null)
+        if (uriString != null) {
+            try {
+                safUri = Uri.parse(uriString)
+                android.util.Log.d("BatteryHealth", "恢复 SAF URI: $safUri")
+            } catch (e: Exception) {
+                android.util.Log.e("BatteryHealth", "恢复 URI 失败: ${e.message}")
+            }
+        }
+    }
+
+    private fun saveUri(uri: Uri) {
+        try {
+            val prefs: SharedPreferences = getSharedPreferences(PREF_NAME, Context.MODE_PRIVATE)
+            prefs.edit().putString(KEY_SAF_URI, uri.toString()).apply()
+            android.util.Log.d("BatteryHealth", "保存 SAF URI: $uri")
+        } catch (e: Exception) {
+            android.util.Log.e("BatteryHealth", "保存 URI 失败: ${e.message}")
+        }
+    }
+
     private fun sendChargeState(isCharging: Boolean) {
         val chargeType = if (isCharging) {
             val batteryIntent = registerReceiver(null, IntentFilter(Intent.ACTION_BATTERY_CHANGED))
@@ -66,7 +92,6 @@ class MainActivity : FlutterActivity() {
                 status == BatteryManager.BATTERY_STATUS_FULL
     }
 
-    // ---------- SAF 方法 ----------
     private fun openFolderPicker() {
         try {
             val intent = Intent(Intent.ACTION_OPEN_DOCUMENT_TREE).apply {
@@ -100,6 +125,8 @@ class MainActivity : FlutterActivity() {
                     val takeFlags = Intent.FLAG_GRANT_READ_URI_PERMISSION or Intent.FLAG_GRANT_WRITE_URI_PERMISSION
                     contentResolver.takePersistableUriPermission(uri, takeFlags)
                     safUri = uri
+                    // 🟢 保存到 SharedPreferences
+                    saveUri(uri)
                     android.util.Log.d("BatteryHealth", "SAF URI: $uri")
                     safResult?.success(uri.toString())
                 } catch (e: Exception) {
@@ -114,27 +141,36 @@ class MainActivity : FlutterActivity() {
     }
 
     private fun getTreeDocId(): String? {
+        android.util.Log.d("BatteryHealth", "getTreeDocId: safUri = $safUri")
         return safUri?.let { DocumentsContract.getTreeDocumentId(it) }
     }
 
     private fun listFiles(): List<String> {
+        android.util.Log.d("BatteryHealth", "listFiles 被调用")
         val result = mutableListOf<String>()
         val docId = getTreeDocId()
-        if (docId == null || docId.isEmpty()) return result
+        android.util.Log.d("BatteryHealth", "docId = $docId")
+        if (docId == null || docId.isEmpty()) {
+            android.util.Log.e("BatteryHealth", "docId 为空")
+            return result
+        }
 
         try {
             val childrenUri = DocumentsContract.buildChildDocumentsUriUsingTree(safUri!!, docId)
+            android.util.Log.d("BatteryHealth", "childrenUri = $childrenUri")
             contentResolver.query(childrenUri, null, null, null, null)?.use { cursor ->
                 val nameIndex = cursor.getColumnIndex(OpenableColumns.DISPLAY_NAME)
                 while (cursor.moveToNext()) {
                     val name = cursor.getString(nameIndex)
                     if (name != null) {
+                        android.util.Log.d("BatteryHealth", "找到文件: $name")
                         result.add(name)
                     }
                 }
             }
+            android.util.Log.d("BatteryHealth", "共找到 ${result.size} 个文件")
         } catch (e: Exception) {
-            android.util.Log.e("BatteryHealth", "列出文件失败: ${e.message}")
+            android.util.Log.e("BatteryHealth", "列出文件失败: ${e.message}", e)
         }
         return result
     }
@@ -178,11 +214,9 @@ class MainActivity : FlutterActivity() {
         return fileUri?.let { readFile(it) }
     }
 
-    // ---------- Flutter 通道配置 ----------
     override fun configureFlutterEngine(@NonNull flutterEngine: FlutterEngine) {
         super.configureFlutterEngine(flutterEngine)
 
-        // 充电状态通道
         MethodChannel(flutterEngine.dartExecutor.binaryMessenger, CHARGE_CHANNEL)
             .setMethodCallHandler { call, result ->
                 if (call.method == "getChargeState") {
@@ -205,7 +239,6 @@ class MainActivity : FlutterActivity() {
                 }
             }
 
-        // SAF 通道
         MethodChannel(flutterEngine.dartExecutor.binaryMessenger, SAF_CHANNEL)
             .setMethodCallHandler { call, result ->
                 when (call.method) {
@@ -233,7 +266,6 @@ class MainActivity : FlutterActivity() {
                 }
             }
 
-        // 充电状态事件通道
         EventChannel(flutterEngine.dartExecutor.binaryMessenger, EVENT_CHANNEL)
             .setStreamHandler(
                 object : EventChannel.StreamHandler {