Do not crash on wrong URL

README.md

@@ -1,52 +1,15 @@
-Android RecyclerView Sample (Kotlin)
+# ntfy Android App
-====================================
+This is the Android app for [ntfy](https://github.com/binwiederhier/ntfy) ([ntfy.sh](https://ntfy.sh)). 
+**It is very much work in progress. Also: I'm new to Android development, so I'm still learning.**
 
-This application implements a RecyclerView in Kotlin with ListAdapter, onClickListener 
+## ...
-and Headers. If you are looking for a simpler sample, look at the RecyclerViewSimple sample
+...
-in the directory.
 
+## License
+Made with ❤️ by [Philipp C. Heckel](https://heckel.io), distributed under the [Apache License 2.0](LICENSE).
 
-Introduction
+This app is heavily based on:
-------------
+* [RecyclerViewKotlin](https://github.com/android/views-widgets-samples/tree/main/RecyclerViewKotlin) (Apache 2.0)
+* [Just another Hacker News Android client](https://github.com/manoamaro/another-hacker-news-client) (MIT)
 
-Sample demonstrating the use of [RecyclerView][1] to layout elements with a
+Thanks to these projects for allowing me to copy-paste a lot.
-[LinearLayoutManager][2].
-
-[RecyclerView][1] can display large datasets that can be scrolled
-efficiently by recycling a limited number of views. [ListAdapter][3] is used to 
-efficiently compute diffs when items are added/removed from the list. Click listeners can be
-defined when [ViewHolder][4] views are instantiated. 
-
-
-[1]: https://developer.android.com/reference/kotlin/androidx/recyclerview/widget/RecyclerView
-[2]: https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager
-[3]: https://developer.android.com/reference/androidx/recyclerview/widget/ListAdapter
-[4]: https://developer.android.com/reference/androidx/recyclerview/widget/RecyclerView.ViewHolder
-
-Pre-requisites
---------------
-
-- Android SDK 27
-- Android Gradle Plugin 3.0
-- Android Support Repository
-
-Screenshots
--------------
-
-![image](https://user-images.githubusercontent.com/46006059/98028846-8b6df700-1dc3-11eb-9f0b-ad93569be189.png)
-
-Getting Started
----------------
-
-To build this project, use "Import Project" in Android Studio.
-
-Support
--------
-
-- Stack Overflow: http://stackoverflow.com/questions/tagged/android
-
-If you've found an error in this sample, please file an issue:
-https://github.com/android/views-widgets
-
-Patches are encouraged, and may be submitted by forking this project and
-submitting a pull request through GitHub. Please see CONTRIBUTING.md for more details.

app/src/main/java/io/heckel/ntfy/data/DataSource.kt

@@ -22,8 +22,7 @@ import androidx.lifecycle.MutableLiveData
 
 /* Handles operations on topicsLiveData and holds details about it. */
 class DataSource(resources: Resources) {
-    private val initialTopicList: List<Topic> = mutableListOf()
+    private val topicsLiveData: MutableLiveData<List<Topic>> = MutableLiveData(mutableListOf())
-    private val topicsLiveData = MutableLiveData(initialTopicList)
 
     /* Adds topic to liveData and posts value. */
     fun addTopic(topic: Topic) {

app/src/main/java/io/heckel/ntfy/data/NtfyApi.kt

@@ -11,34 +11,27 @@ import java.io.IOException
 import java.net.HttpURLConnection
 import java.net.URL
 
+data class Event(val name: String = "", val data: JsonObject = JsonObject())
+
 class NtfyApi(context: Context) {
     private val gson = GsonBuilder().create()
 
-    private suspend fun getStreamConnection(url: String): HttpURLConnection =
+    fun createEventsFlow(url: String): Flow<Event> = flow {
-        withContext(Dispatchers.IO) {
-            return@withContext (URL(url).openConnection() as HttpURLConnection).also {
-                it.setRequestProperty("Accept", "text/event-stream")
-                it.doInput = true
-            }
-        }
-
-    data class Event(val name: String = "", val data: JsonObject = JsonObject())
-
-    fun getEventsFlow(): Flow<Event> = flow {
         coroutineScope {
-            println("111111111111")
+            val conn = getStreamConnection(url)
-
-            val conn = getStreamConnection("https://ntfy.sh/_phil/sse")
             println("2222222222222")
             val input = conn.inputStream.bufferedReader()
             try {
                 conn.connect()
                 var event = Event()
-                println("CCCCCCCCCCCCCCc")
                 while (isActive) {
                     val line = input.readLine()
                     println("PHIL: " + line)
                     when {
+                        line == null -> {
+                            this.cancel(CancellationException("EOF"))
+                            break
+                        }
                         line.startsWith("event:") -> {
                             event = event.copy(name = line.substring(6).trim())
                         }
@@ -65,4 +58,11 @@ class NtfyApi(context: Context) {
             }
         }
     }
+
+    private suspend fun getStreamConnection(url: String): HttpURLConnection =
+        withContext(Dispatchers.IO) {
+            return@withContext (URL(url).openConnection() as HttpURLConnection).also {
+                it.doInput = true
+            }
+        }
 }

app/src/main/java/io/heckel/ntfy/detail/TopicDetailActivity.kt

@@ -25,7 +25,6 @@ import io.heckel.ntfy.R
 import io.heckel.ntfy.list.TOPIC_ID
 
 class TopicDetailActivity : AppCompatActivity() {
-
     private val topicDetailViewModel by viewModels<TopicDetailViewModel> {
         TopicDetailViewModelFactory(this)
     }

app/src/main/java/io/heckel/ntfy/list/TopicsListActivity.kt

@@ -34,6 +34,7 @@ import androidx.recyclerview.widget.RecyclerView
 import io.heckel.ntfy.R
 import io.heckel.ntfy.add.AddTopicActivity
 import io.heckel.ntfy.add.TOPIC_URL
+import io.heckel.ntfy.data.Event
 import io.heckel.ntfy.data.NtfyApi
 import io.heckel.ntfy.data.Topic
 import io.heckel.ntfy.detail.TopicDetailActivity
@@ -59,7 +60,7 @@ class TopicsListActivity : AppCompatActivity() {
         val recyclerView: RecyclerView = findViewById(R.id.recycler_view)
         recyclerView.adapter = adapter
 
-        topicsListViewModel.topicsLiveData.observe(this) {
+        topicsListViewModel.topics.observe(this) {
             it?.let {
                 adapter.submitList(it as MutableList<Topic>)
             }
@@ -71,8 +72,10 @@ class TopicsListActivity : AppCompatActivity() {
         }
 
         createNotificationChannel()
+    }
 
-        api.getEventsFlow().asLiveData(Dispatchers.IO).observe(this) { event ->
+    private fun startFlow(url: String) {
+        api.createEventsFlow(url).asLiveData(Dispatchers.IO).observe(this) { event ->
             this.lifecycleScope.launch(Dispatchers.Main) {
                 withContext(Dispatchers.IO) {
                     handleEvent(event)
@@ -80,8 +83,7 @@ class TopicsListActivity : AppCompatActivity() {
             }
         }
     }
-
+    private fun handleEvent(event: Event) {
-    private fun handleEvent(event: NtfyApi.Event) {
         if (event.data.isJsonNull || !event.data.has("message")) {
             return
         }
@@ -117,8 +119,9 @@ class TopicsListActivity : AppCompatActivity() {
         /* Inserts topic into viewModel. */
         if (requestCode == newTopicActivityRequestCode && resultCode == Activity.RESULT_OK) {
             intentData?.let { data ->
-                val topicName = data.getStringExtra(TOPIC_URL)
+                val topicUrl = data.getStringExtra(TOPIC_URL) ?: return
-                topicsListViewModel.insertTopic(topicName)
+                startFlow(topicUrl)
+                topicsListViewModel.insertTopic(topicUrl)
             }
         }
     }

app/src/main/java/io/heckel/ntfy/list/TopicsListViewModel.kt

@@ -17,6 +17,7 @@
 package io.heckel.ntfy.list
 
 import android.content.Context
+import androidx.lifecycle.LiveData
 import androidx.lifecycle.ViewModel
 import androidx.lifecycle.ViewModelProvider
 import io.heckel.ntfy.data.DataSource
@@ -24,26 +25,18 @@ import io.heckel.ntfy.data.Topic
 import kotlin.random.Random
 
 class TopicsListViewModel(val dataSource: DataSource) : ViewModel() {
+    val topics: LiveData<List<Topic>> = dataSource.getTopicList()
 
-    val topicsLiveData = dataSource.getTopicList()
+    fun insertTopic(topicUrl: String) {
-
-    /* If the name and description are present, create new Topic and add it to the datasource */
-    fun insertTopic(topicUrl: String?) {
-        if (topicUrl == null) {
-            return
-        }
-
         val newTopic = Topic(
             Random.nextLong(),
             topicUrl
         )
-
         dataSource.addTopic(newTopic)
     }
 }
 
 class TopicsListViewModelFactory(private val context: Context) : ViewModelProvider.Factory {
-
     override fun <T : ViewModel> create(modelClass: Class<T>): T {
         if (modelClass.isAssignableFrom(TopicsListViewModel::class.java)) {
             @Suppress("UNCHECKED_CAST")