fix(android): recover remote loads after connectivity returns

packages/android/templates/MainActivity.kt.templatemodified+71-1

Changes to packages/android/templates/MainActivity.kt.template

		@@ -1,10 +1,14 @@
1	1	package
2	2
3	3	import android.annotation.SuppressLint
	4	+import android.content.Context
4	5	import android.os.Bundle
5	6	import android.content.Intent
6	7	import android.graphics.Bitmap
	8	+import android.net.ConnectivityManager
	9	+import android.net.Network
7	10	import android.net.Uri
	11	+import android.util.Log
8	12	import android.webkit.WebResourceRequest
9	13	import android.webkit.WebResourceError
10	14	import android.webkit.WebResourceResponse
		⋯8 linesShow the 8 lines above this hunk@@ -19,6 +23,20 @@ import org.json.JSONObject
19	23	import java.io.FileNotFoundException
20	24	import java.net.URLConnection
21	25
	26	+/** Main-frame failures for which the bundled app is an honest fallback (#254). */
	27	+object CraftLoadFailure {
	28	+ fun isUnreachable(errorCode: Int): Boolean = when (errorCode) {
	29	+ WebViewClient.ERROR_HOST_LOOKUP,
	30	+ WebViewClient.ERROR_CONNECT,
	31	+ WebViewClient.ERROR_TIMEOUT,
	32	+ // Android uses ERROR_IO for connection interruptions as well as local
	33	+ // I/O failures. Keep it here deliberately: it is the closest Android
	34	+ // equivalent to iOS's NSURLErrorNetworkConnectionLost.
	35	+ WebViewClient.ERROR_IO -> true
	36	+ else -> false
	37	+ }
	38	+}
	39	+
22	40	class MainActivity : AppCompatActivity() {
23	41	private lateinit var webView: WebView
24	42	private lateinit var craftBridge: CraftBridge
		⋯7 linesShow the 7 lines above this hunk@@ -32,6 +50,28 @@ class MainActivity : AppCompatActivity() {
32	50	.build()
33	51	}
34	52	private var loadedBundledFallback = false
	53	+ private lateinit var connectivityManager: ConnectivityManager
	54	+ @Volatile
	55	+ private var isConnected = false
	56	+ private var networkMonitoringRegistered = false
	57	+ private val networkCallback = object : ConnectivityManager.NetworkCallback() {
	58	+ override fun onAvailable(network: Network) {
	59	+ val wasConnected = isConnected
	60	+ isConnected = true
	61	+ if (!wasConnected && isConnected) {
	62	+ runOnUiThread {
	63	+ returnFromBundledFallback("the network came back")
	64	+ }
	65	+ }
	66	+ }
	67	+
	68	+ override fun onLost(network: Network) {
	69	+ // A second transport can already be the default by the time the
	70	+ // old one reports its loss, so read current state instead of
	71	+ // blindly turning the latch off.
	72	+ isConnected = connectivityManager.activeNetwork != null
	73	+ }
	74	+ }
35	75
36	76	@SuppressLint("SetJavaScriptEnabled")
37	77	override fun onCreate(savedInstanceState: Bundle?) {
		⋯30 linesShow the 30 lines above this hunk@@ -68,6 +108,7 @@ class MainActivity : AppCompatActivity() {
68	108
69	109	setupWebView()
70	110	loadContent()
	111	+ setupNetworkMonitoring()
71	112	}
72	113
73	114	@SuppressLint("SetJavaScriptEnabled")
		⋯39 linesShow the 39 lines above this hunk@@ -113,7 +154,13 @@ class MainActivity : AppCompatActivity() {
113	154
114	155	override fun onReceivedError(view: WebView?, request: WebResourceRequest?, error: WebResourceError?) {
115	156	super.onReceivedError(view, request, error)
116		- if (request?.isForMainFrame == true && hasBundledFallback && !loadedBundledFallback) {
	157	+ if (
	158	+ request?.isForMainFrame == true &&
	159	+ error != null &&
	160	+ CraftLoadFailure.isUnreachable(error.errorCode) &&
	161	+ hasBundledFallback &&
	162	+ !loadedBundledFallback
	163	+ ) {
117	164	loadedBundledFallback = true
118	165	webView.loadUrl(BUNDLED_APP_URL)
119	166	}
		⋯6 linesShow the 6 lines above this hunk@@ -126,6 +173,23 @@ class MainActivity : AppCompatActivity() {
126	173	webView.addJavascriptInterface(craftBridge, "CraftAndroid")
127	174	}
128	175
	176	+ private fun setupNetworkMonitoring() {
	177	+ if (!hasBundledFallback || devServerUrl == null) return
	178	+ connectivityManager = getSystemService(Context.CONNECTIVITY_SERVICE) as ConnectivityManager
	179	+ isConnected = connectivityManager.activeNetwork != null
	180	+ connectivityManager.registerDefaultNetworkCallback(networkCallback)
	181	+ networkMonitoringRegistered = true
	182	+ }
	183	+
	184	+ /** Leave the bundled copy for the configured remote origin again. */
	185	+ private fun returnFromBundledFallback(reason: String) {
	186	+ val remoteUrl = devServerUrl ?: return
	187	+ if (!loadedBundledFallback) return
	188	+ loadedBundledFallback = false
	189	+ Log.i(TAG, "$reason; loading $remoteUrl again instead of the bundled copy")
	190	+ webView.loadUrl(remoteUrl)
	191	+ }
	192	+
129	193	private fun loadContent() {
130	194	// Check for dev server URL in config
131	195	val remoteUrl = devServerUrl
		⋯102 linesShow the 102 lines above this hunk@@ -234,6 +298,7 @@ class MainActivity : AppCompatActivity() {
234	298	override fun onResume() {
235	299	super.onResume()
236	300	webView.onResume()
	301	+ returnFromBundledFallback("the app returned to the foreground")
237	302	}
238	303
239	304	override fun onPause() {
		⋯2 linesShow the 2 lines above this hunk@@ -242,6 +307,10 @@ class MainActivity : AppCompatActivity() {
242	307	}
243	308
244	309	override fun onDestroy() {
	310	+ if (networkMonitoringRegistered) {
	311	+ connectivityManager.unregisterNetworkCallback(networkCallback)
	312	+ networkMonitoringRegistered = false
	313	+ }
245	314	craftBridge.close()
246	315	webView.destroy()
247	316	super.onDestroy()
		⋯15 linesShow the 15 lines above this hunk@@ -263,6 +332,7 @@ class MainActivity : AppCompatActivity() {
263	332	}
264	333
265	334	companion object {
	335	+ private const val TAG = "CraftMainActivity"
266	336	private const val BUNDLED_APP_HOST = "appassets.androidplatform.net"
267	337	private const val BUNDLED_APP_ORIGIN = "https://appassets.androidplatform.net"
268	338	private const val BUNDLED_APP_URL = "$BUNDLED_APP_ORIGIN/"