From 477ec3e1823df0ca245e9e0d469da8cf4958c774 Mon Sep 17 00:00:00 2001
From: Canny <canny1913@outlook.com>
Date: Fri, 7 Oct 2022 19:17:23 +0300
Subject: [PATCH] feat: remove observer when ViewModel is cleared

---
 .../manager/patcher/worker/PatcherWorker.kt   |  2 +-
 .../manager/ui/screen/PatchingScreen.kt       |  4 +-
 .../ui/viewmodel/PatchingScreenViewModel.kt   | 47 +++++++++----------
 3 files changed, 27 insertions(+), 26 deletions(-)

diff --git a/app/src/main/java/app/revanced/manager/patcher/worker/PatcherWorker.kt b/app/src/main/java/app/revanced/manager/patcher/worker/PatcherWorker.kt
index 693b52a..388f8b3 100644
--- a/app/src/main/java/app/revanced/manager/patcher/worker/PatcherWorker.kt
+++ b/app/src/main/java/app/revanced/manager/patcher/worker/PatcherWorker.kt
@@ -149,7 +149,7 @@ class PatcherWorker(context: Context, parameters: WorkerParameters, private val
             Logging.log += "Merging integrations\n"
             patcher.addFiles(listOf(integrations)) {}
 
-            Logging.log += "Applying ${patches.size} patch(es)"
+            Logging.log += "Applying ${patches.size} patch(es)\n"
             patcher.executePatches().forEach { (patch, result) ->
 
                 if (result.isFailure) {
diff --git a/app/src/main/java/app/revanced/manager/ui/screen/PatchingScreen.kt b/app/src/main/java/app/revanced/manager/ui/screen/PatchingScreen.kt
index 8996d17..326e8ed 100644
--- a/app/src/main/java/app/revanced/manager/ui/screen/PatchingScreen.kt
+++ b/app/src/main/java/app/revanced/manager/ui/screen/PatchingScreen.kt
@@ -11,6 +11,7 @@ import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.Done
 import androidx.compose.material3.*
 import androidx.compose.runtime.*
+import androidx.compose.runtime.saveable.rememberSaveable
 import androidx.compose.ui.Alignment
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.style.TextOverflow
@@ -30,7 +31,7 @@ fun PatchingScreen(
     navigator: BackstackNavigator<AppDestination>,
     vm: PatchingScreenViewModel = getViewModel()
 ) {
-    var patching by mutableStateOf(false)
+    var patching by rememberSaveable {mutableStateOf(false)}
     val scrollState = rememberScrollState()
     val coroutineScope = rememberCoroutineScope()
     LaunchedEffect(patching) {
@@ -96,6 +97,7 @@ fun PatchingScreen(
                             )
                             Text(text = "Completed!", fontSize = 30.sp)
                         }
+                        PatchingScreenViewModel.Status.Idle -> {}
                     }
                 }
             }
diff --git a/app/src/main/java/app/revanced/manager/ui/viewmodel/PatchingScreenViewModel.kt b/app/src/main/java/app/revanced/manager/ui/viewmodel/PatchingScreenViewModel.kt
index edb4d7c..da215de 100644
--- a/app/src/main/java/app/revanced/manager/ui/viewmodel/PatchingScreenViewModel.kt
+++ b/app/src/main/java/app/revanced/manager/ui/viewmodel/PatchingScreenViewModel.kt
@@ -1,59 +1,58 @@
 package app.revanced.manager.ui.viewmodel
 
 import android.app.Application
-import android.util.Log
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.setValue
+import androidx.lifecycle.Observer
 import androidx.lifecycle.ViewModel
 import androidx.work.*
 import app.revanced.manager.patcher.worker.PatcherWorker
-import app.revanced.manager.util.tag
 
 class PatchingScreenViewModel(val app: Application) : ViewModel() {
 
-    // create worker
-    private val patcherWorker = OneTimeWorkRequest.Builder(PatcherWorker::class.java)
+    private val patcherWorker = OneTimeWorkRequest.Builder(PatcherWorker::class.java) // create Worker
         .setExpedited(OutOfQuotaPolicy.RUN_AS_NON_EXPEDITED_WORK_REQUEST)
         .setInputData(
             Data.Builder()
                 .build()
         ).build()
 
-    var status by mutableStateOf<Status>(Status.Patching)
+    private val liveData = WorkManager.getInstance(app).getWorkInfoByIdLiveData(patcherWorker.id) // get LiveData
+
+    private val observer = Observer { workInfo: WorkInfo -> // observer for observing patch status
+        status = when (workInfo.state) {
+            WorkInfo.State.RUNNING -> Status.Patching
+            WorkInfo.State.SUCCEEDED -> Status.Success
+            WorkInfo.State.FAILED -> Status.Failure
+            else -> Status.Idle
+        }
+    }
+
+    var status by mutableStateOf<Status>(Status.Idle)
 
     sealed class Status {
+        object Idle : Status()
         object Patching : Status()
         object Success : Status()
         object Failure : Status()
     }
 
-
     fun startPatcher() {
-        cancelPatching() // cancel existing patching process
-        Logging.log = "" // and clear logs
-
+        cancelPatching() //  cancel patching if its still running
         WorkManager.getInstance(app)
-            .enqueueUniqueWork("patching", ExistingWorkPolicy.KEEP, patcherWorker)
-        status = Status.Patching // set status
-        Log.d(tag, "Created worker.")
-
-        val liveData = WorkManager.getInstance(app).getWorkInfoByIdLiveData(patcherWorker.id) // live data for observing
-
-        liveData.observeForever { workInfo: WorkInfo -> // shitty solution but it works
-            status = when (workInfo.state) {
-                WorkInfo.State.SUCCEEDED -> Status.Success
-                WorkInfo.State.FAILED -> Status.Failure
-                else -> Status.Patching
-            }
-        }
-
-        Log.d(tag, "Worker finished.")
+            .enqueueUniqueWork("patching", ExistingWorkPolicy.KEEP, patcherWorker) // enqueue patching process
+        liveData.observeForever(observer) // start observing patch status
     }
 
     private fun cancelPatching() {
         WorkManager.getInstance(app).cancelWorkById(patcherWorker.id)
     }
+
+    override fun onCleared() {
+        super.onCleared()
+        liveData.removeObserver(observer) // remove observer when ViewModel is destroyed
+    }
 }
 
 object Logging {