Display an error screen when EmojiSearch crashes

cashapp · Oct 29, 2023 · 6317805 · 6317805
1 parent a34ebe7
commit 6317805
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diff --git a/...iews/src/main/kotlin/com/example/redwood/emojisearch/android/views/EmojiSearchActivity.kt b/...iews/src/main/kotlin/com/example/redwood/emojisearch/android/views/EmojiSearchActivity.kt
@@ -18,11 +18,14 @@ package com.example.redwood.emojisearch.android.views
 import android.annotation.SuppressLint
 import android.os.Bundle
 import android.util.Log
+import android.view.ViewGroup.LayoutParams.MATCH_PARENT
+import android.widget.LinearLayout
 import androidx.activity.ComponentActivity
 import androidx.core.view.WindowCompat
 import app.cash.redwood.compose.AndroidUiDispatcher.Companion.Main
 import app.cash.redwood.layout.view.ViewRedwoodLayoutWidgetFactory
 import app.cash.redwood.lazylayout.view.ViewRedwoodLazyLayoutWidgetFactory
+import app.cash.redwood.treehouse.CodeListener
 import app.cash.redwood.treehouse.EventListener
 import app.cash.redwood.treehouse.TreehouseApp
 import app.cash.redwood.treehouse.TreehouseAppFactory
@@ -78,11 +81,22 @@ class EmojiSearchActivity : ComponentActivity() {
     }
 
     treehouseLayout = TreehouseLayout(this, widgetSystem, onBackPressedDispatcher).apply {
-      treehouseContentSource.bindWhenReady(this, treehouseApp)
+      treehouseContentSource.bindWhenReady(this, treehouseApp, codeListener)
     }
     setContentView(treehouseLayout)
   }
 
+  private val codeListener: CodeListener = object : CodeListener() {
+    override fun onUncaughtException(view: TreehouseView<*>, e: Throwable) {
+      val treehouseLayout = view as TreehouseLayout
+      treehouseLayout.reset()
+      treehouseLayout.addView(
+        ExceptionView(treehouseLayout, e),
+        LinearLayout.LayoutParams(MATCH_PARENT, MATCH_PARENT),
+      )
+    }
+  }
+
   private val appEventListener: EventListener = object : EventListener() {
     private var success = true
     private var snackbar: Snackbar? = null

diff --git a/...roid-views/src/main/kotlin/com/example/redwood/emojisearch/android/views/ExceptionView.kt b/...roid-views/src/main/kotlin/com/example/redwood/emojisearch/android/views/ExceptionView.kt
@@ -0,0 +1,84 @@
+/*
+ * Copyright (C) 2023 Square, Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.example.redwood.emojisearch.android.views
+
+import android.annotation.SuppressLint
+import android.graphics.Color
+import android.text.TextUtils
+import android.view.Gravity.CENTER
+import android.view.ViewGroup.LayoutParams.MATCH_PARENT
+import android.view.ViewGroup.LayoutParams.WRAP_CONTENT
+import android.widget.LinearLayout
+import androidx.appcompat.widget.AppCompatTextView
+import app.cash.redwood.treehouse.TreehouseLayout
+import app.cash.redwood.ui.Density
+import app.cash.redwood.ui.dp
+
+/**
+ * Renders an emoji, plus the first line of the exception message, centered and wrapped. The view
+ * has a light-yellow background.
+ *
+ * ```
+ *                         🦨
+ *          app.cash.zipline.ZiplineException
+ *                  RuntimeException
+ *                        boom!
+ * ```
+ */
+@SuppressLint("ViewConstructor")
+internal class ExceptionView(
+  parent: TreehouseLayout,
+  private val exception: Throwable,
+) : LinearLayout(parent.context) {
+
+  init {
+    orientation = VERTICAL
+    gravity = CENTER
+    setBackgroundColor(Color.argb(255, 255, 250, 225))
+
+    addView(
+      AppCompatTextView(context).apply {
+        textAlignment = TEXT_ALIGNMENT_CENTER
+        setTextColor(Color.BLACK)
+        textSize = 40f
+        text = "🦨"
+      },
+    )
+
+    addView(
+      AppCompatTextView(context).apply {
+        textAlignment = TEXT_ALIGNMENT_CENTER
+        setTextColor(Color.BLACK)
+        textSize = 16f
+        text = exception.toString().substringBefore("\n").replace(": ", "\n")
+        ellipsize = TextUtils.TruncateAt.END
+      },
+    )
+  }
+
+  override fun generateDefaultLayoutParams(): LayoutParams {
+    return LayoutParams(MATCH_PARENT, WRAP_CONTENT).apply {
+      with(Density(resources)) {
+        setMargins(
+          10f.dp.toPxInt(),
+          5f.dp.toPxInt(),
+          10f.dp.toPxInt(),
+          5f.dp.toPxInt(),
+        )
+      }
+    }
+  }
+}
diff --git a/.../presenter/src/commonMain/kotlin/com/example/redwood/emojisearch/presenter/EmojiSearch.kt b/.../presenter/src/commonMain/kotlin/com/example/redwood/emojisearch/presenter/EmojiSearch.kt
@@ -137,10 +137,12 @@ private fun LazyColumn(
     TextInput(
       state = TextFieldState(searchTerm.text),
       hint = "Search",
-      onChange = { it ->
-        searchTerm = it
-
-        if (it.text == "ex") throw RuntimeException("boom")
+      onChange = { textFieldState ->
+        // Make it easy to trigger a crash to manually test exception handling!
+        if (textFieldState.text == "crash") {
+          throw RuntimeException("boom!")
+        }
+        searchTerm = textFieldState
       },
     )
     LazyColumn(