Add simple error handling

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

app/src/main/java/com/example/allyoucantweet/ui/MainActivity.kt

@@ -3,12 +3,14 @@ package com.example.allyoucantweet.ui
 import android.os.Bundle
 import android.util.Log
 import android.view.animation.AlphaAnimation
-import android.view.animation.Animation
 import android.view.animation.DecelerateInterpolator
 import androidx.appcompat.app.AppCompatActivity
 import com.example.allyoucantweet.R
 import com.example.allyoucantweet.databinding.ActivityMainBinding
 import com.example.allyoucantweet.network.service.AYCTService
+import com.example.allyoucantweet.utils.empty
+import com.example.allyoucantweet.utils.gone
+import com.example.allyoucantweet.utils.show
 import com.google.gson.GsonBuilder
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.Dispatchers.IO
@@ -35,27 +37,45 @@ class MainActivity : AppCompatActivity() {
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
         setContentView(binding.root)
+
+        binding.retry.setOnClickListener {
+            it.gone()
+            binding.hello.gone()
+            getHelloMessage()
+        }
     }
 
     override fun onResume() {
         super.onResume()
-        CoroutineScope(IO).launch {
+        getHelloMessage()
-            try {
+    }
-                val hello = service.getHello()
+
-                Log.d("AYCT", "hello: $hello")
+    private fun getHelloMessage() = CoroutineScope(IO).launch {
-                runOnUiThread {
+        runOnUiThread {
-                    binding.hello.apply {
+            binding.progressCircular.show()
-                        text = hello
+            binding.retry.gone()
-                        val fadeIn: Animation = AlphaAnimation(0f, 1f).apply {
+        }
-                            interpolator = DecelerateInterpolator()
+        var message = String.empty()
-                            duration = 1500
+        try {
-                        }
+            message = service.getHello()
-                        animation = fadeIn
+        } catch (e: Exception) {
-                    }
+            message = getString(R.string.sth_went_wrong)
+            runOnUiThread { binding.retry.show() }
+            Log.d("AYCT", "error message: ${e.message}")
+        } finally {
+            runOnUiThread {
+                binding.hello.show()
+                binding.progressCircular.gone()
+                binding.hello.apply {
+                    text = message
+                    animation = this@MainActivity.getAnimation()
                 }
-            } catch (e: Exception) {
-                Log.d("AYCT", "error message: ${e.message}")
             }
         }
     }
+
+    private fun getAnimation() = AlphaAnimation(0f, 1f).apply {
+        interpolator = DecelerateInterpolator()
+        duration = 1500
+    }
 }

app/src/main/java/com/example/allyoucantweet/utils/Extensions.kt

@@ -0,0 +1,13 @@
+package com.example.allyoucantweet.utils
+
+import android.view.View
+
+fun View.show() = this.apply {
+    visibility = View.VISIBLE
+}
+
+fun View.gone() = this.apply {
+    visibility = View.GONE
+}
+
+fun String.Companion.empty() = ""

app/src/main/res/drawable/ic_sync.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#FFFFFF"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M12,4L12,1L8,5l4,4L12,6c3.31,0 6,2.69 6,6 0,1.01 -0.25,1.97 -0.7,2.8l1.46,1.46C19.54,15.03 20,13.57 20,12c0,-4.42 -3.58,-8 -8,-8zM12,18c-3.31,0 -6,-2.69 -6,-6 0,-1.01 0.25,-1.97 0.7,-2.8L5.24,7.74C4.46,8.97 4,10.43 4,12c0,4.42 3.58,8 8,8v3l4,-4 -4,-4v3z"/>
+</vector>

app/src/main/res/layout/activity_main.xml

@@ -5,27 +5,53 @@
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="@color/brand"
+    android:padding="@dimen/app_margin"
     tools:context=".ui.MainActivity">
 
-    <com.google.android.material.imageview.ShapeableImageView
+    <ImageView
         android:layout_width="200dp"
         android:layout_height="200dp"
+        android:contentDescription="@string/app_name"
         android:src="@mipmap/ic_launcher_foreground"
         app:layout_constraintBottom_toBottomOf="@id/hello"
         app:layout_constraintEnd_toEndOf="parent"
         app:layout_constraintStart_toStartOf="parent"
         app:layout_constraintTop_toTopOf="parent" />
 
+    <ProgressBar
+        android:id="@+id/progress_circular"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:visibility="gone"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+    <com.google.android.material.button.MaterialButton
+        android:id="@+id/retry"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/retry"
+        android:visibility="gone"
+        app:icon="@drawable/ic_sync"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toBottomOf="@id/hello" />
+
     <TextView
         android:id="@+id/hello"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
+        android:textAlignment="center"
         android:textColor="@color/brand_text"
         android:textSize="30sp"
         android:textStyle="bold"
         app:layout_constraintBottom_toBottomOf="parent"
         app:layout_constraintLeft_toLeftOf="parent"
         app:layout_constraintRight_toRightOf="parent"
-        app:layout_constraintTop_toTopOf="parent" />
+        app:layout_constraintTop_toTopOf="parent"
+        tools:text="Hello There" />
 
 </androidx.constraintlayout.widget.ConstraintLayout>

app/src/main/res/values-night/themes.xml

@@ -6,7 +6,7 @@
         <item name="colorPrimaryVariant">@color/brand</item>
         <item name="colorOnPrimary">@color/black</item>
         <!-- Secondary brand color. -->
-        <item name="colorSecondary">@color/teal_200</item>
+        <item name="colorSecondary">@color/brand_text</item>
         <item name="colorSecondaryVariant">@color/teal_200</item>
         <item name="colorOnSecondary">@color/black</item>
         <!-- Status bar color. -->

app/src/main/res/values/dimens.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <dimen name="app_margin">16dp</dimen>
+</resources>

app/src/main/res/values/strings.xml

@@ -1,4 +1,6 @@
 <resources>
     <string name="app_name">AllYouCanTweet</string>
     <string name="base_url" translatable="false">https://young-spire-63034.herokuapp.com/</string>
+    <string name="retry">retry</string>
+    <string name="sth_went_wrong">Ups… Something went wrong!</string>
 </resources>

app/src/main/res/values/themes.xml

@@ -6,7 +6,7 @@
         <item name="colorPrimaryVariant">@color/brand</item>
         <item name="colorOnPrimary">@color/white</item>
         <!-- Secondary brand color. -->
-        <item name="colorSecondary">@color/teal_200</item>
+        <item name="colorSecondary">@color/brand_text</item>
         <item name="colorSecondaryVariant">@color/teal_700</item>
         <item name="colorOnSecondary">@color/black</item>
         <!-- Status bar color. -->