From 853059355cead729f033129cdf4359da9a0d220d Mon Sep 17 00:00:00 2001
From: Darshan Parajuli <parajulidarshan@gmail.com>
Date: Sun, 19 Aug 2018 12:22:37 -0700
Subject: [PATCH] Observe filter data on `onResume` and dispose it on `onPause`

This prevents the case where the IllegalStateException is thrown
as a result of fragment not being attached to the context at the
time subscribe callback gets run.
---
 .../fragments/filters/FiltersFragment.kt      | 31 +++++++++++++++++--
 1 file changed, 28 insertions(+), 3 deletions(-)

diff --git a/app/src/main/java/com/dp/logcatapp/fragments/filters/FiltersFragment.kt b/app/src/main/java/com/dp/logcatapp/fragments/filters/FiltersFragment.kt
index 65e655e2..75f2a06f 100644
--- a/app/src/main/java/com/dp/logcatapp/fragments/filters/FiltersFragment.kt
+++ b/app/src/main/java/com/dp/logcatapp/fragments/filters/FiltersFragment.kt
@@ -1,5 +1,6 @@
 package com.dp.logcatapp.fragments.filters
 
+import android.annotation.SuppressLint
 import android.arch.lifecycle.ViewModelProviders
 import android.os.Bundle
 import android.support.v7.util.DiffUtil
@@ -19,6 +20,7 @@ import com.dp.logcatapp.fragments.logcatlive.LogcatLiveViewModel
 import com.dp.logcatapp.util.inflateLayout
 import io.reactivex.Flowable
 import io.reactivex.android.schedulers.AndroidSchedulers
+import io.reactivex.disposables.Disposable
 import io.reactivex.schedulers.Schedulers
 
 class FiltersFragment : BaseFragment() {
@@ -40,6 +42,7 @@ class FiltersFragment : BaseFragment() {
     private lateinit var recyclerViewAdapter: MyRecyclerViewAdapter
     private lateinit var linearLayoutManager: LinearLayoutManager
     private lateinit var emptyMessage: TextView
+    private var filterObserver: Disposable? = null
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
@@ -49,15 +52,16 @@ class FiltersFragment : BaseFragment() {
         recyclerViewAdapter = MyRecyclerViewAdapter {
             onRemoveClicked(it)
         }
+    }
 
-        val dao = MyDB.getInstance(activity!!).filterDao()
+    private fun startObservingFilters() {
+        val dao = MyDB.getInstance(context!!).filterDao()
         val flowable = if (isExclusions()) {
             dao.getExclusions()
         } else {
             dao.getFilters()
         }
-
-        flowable.observeOn(AndroidSchedulers.mainThread())
+        filterObserver = flowable.observeOn(AndroidSchedulers.mainThread())
                 .subscribe { list ->
                     val data = list.map {
                         val displayText: String
@@ -102,8 +106,28 @@ class FiltersFragment : BaseFragment() {
                 }
     }
 
+    private fun stopObservingFilters() {
+        filterObserver?.let {
+            if (!it.isDisposed) {
+                it.dispose()
+            }
+        }
+        filterObserver = null
+    }
+
+    override fun onResume() {
+        super.onResume()
+        startObservingFilters()
+    }
+
+    override fun onPause() {
+        super.onPause()
+        stopObservingFilters()
+    }
+
     fun isExclusions() = arguments?.getBoolean(KEY_EXCLUSIONS) ?: false
 
+    @SuppressLint("CheckResult")
     private fun onRemoveClicked(v: View) {
         val pos = linearLayoutManager.getPosition(v)
         if (pos != RecyclerView.NO_POSITION) {
@@ -158,6 +182,7 @@ class FiltersFragment : BaseFragment() {
         }
     }
 
+    @SuppressLint("CheckResult")
     fun addFilter(keyword: String, tag: String, pid: String, tid: String, logLevels: Set<String>) {
         val list = mutableListOf<FilterInfo>()
         val exclude = isExclusions()