error handling in FiltersActivity (#1180)

app/src/main/java/com/keylesspalace/tusky/FiltersActivity.kt

@@ -2,6 +2,7 @@ package com.keylesspalace.tusky
 
 import android.os.Bundle
 import android.view.MenuItem
+import android.view.View
 import android.widget.AdapterView
 import android.widget.ArrayAdapter
 import android.widget.Toast
@@ -10,6 +11,8 @@ import com.keylesspalace.tusky.appstore.EventHub
 import com.keylesspalace.tusky.appstore.PreferenceChangedEvent
 import com.keylesspalace.tusky.entity.Filter
 import com.keylesspalace.tusky.network.MastodonApi
+import com.keylesspalace.tusky.util.hide
+import com.keylesspalace.tusky.util.show
 import kotlinx.android.synthetic.main.activity_filters.*
 import kotlinx.android.synthetic.main.dialog_filter.*
 import kotlinx.android.synthetic.main.toolbar_basic.*
@@ -17,6 +20,7 @@ import okhttp3.ResponseBody
 import retrofit2.Call
 import retrofit2.Callback
 import retrofit2.Response
+import java.io.IOException
 import javax.inject.Inject
 
 class FiltersActivity: BaseActivity() {
@@ -132,24 +136,55 @@ class FiltersActivity: BaseActivity() {
     }
 
     private fun loadFilters() {
+
+        filterMessageView.hide()
+        filtersView.hide()
+        addFilterButton.hide()
+        filterProgressBar.show()
+
         api.filters.enqueue(object : Callback<List<Filter>> {
             override fun onResponse(call: Call<List<Filter>>, response: Response<List<Filter>>) {
-                filters = response.body()!!.filter { filter -> filter.context.contains(context) }.toMutableList()
+                val filterResponse = response.body()
-                refreshFilterDisplay()
+                if(response.isSuccessful && filterResponse != null) {
+
+                    filters = filterResponse.filter { filter -> filter.context.contains(context) }.toMutableList()
+                    refreshFilterDisplay()
+
+                    filtersView.show()
+                    addFilterButton.show()
+                    filterProgressBar.hide()
+                } else {
+                    filterProgressBar.hide()
+                    filterMessageView.show()
+                    filterMessageView.setup(R.drawable.elephant_error,
+                            R.string.error_generic, this@FiltersActivity::reload)
+                }
             }
 
             override fun onFailure(call: Call<List<Filter>>, t: Throwable) {
-                // Anything?
+                filterProgressBar.hide()
+                filterMessageView.show()
+                if (t is IOException) {
+                    filterMessageView.setup(R.drawable.elephant_offline,
+                            R.string.error_network, this@FiltersActivity::reload)
+                } else {
+                    filterMessageView.setup(R.drawable.elephant_error,
+                            R.string.error_generic, this@FiltersActivity::reload)
+                }
             }
         })
     }
 
+    private fun reload(v: View) {
+        loadFilters()
+    }
+
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
 
         setContentView(R.layout.activity_filters)
         setupToolbarBackArrow()
-        filter_floating_add.setOnClickListener {
+        addFilterButton.setOnClickListener {
             showAddFilterDialog()
         }
 

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

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="utf-8"?>
 <androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:tools="http://schemas.android.com/tools"
     xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
     android:id="@+id/activityFilters"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
@@ -15,16 +15,27 @@
         android:layout_height="match_parent"
         app:layout_behavior="@string/appbar_scrolling_view_behavior" />
 
+    <com.keylesspalace.tusky.view.BackgroundMessageView
+        android:id="@+id/filterMessageView"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center" />
+
+    <ProgressBar
+        android:id="@+id/filterProgressBar"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center" />
+
     <com.google.android.material.floatingactionbutton.FloatingActionButton
-        android:id="@+id/filter_floating_add"
+        android:id="@+id/addFilterButton"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_margin="16dp"
         android:contentDescription="@string/filter_addition_dialog_title"
-        app:layout_anchor="@id/filtersView"
-        app:layout_anchorGravity="bottom|end"
         android:src="@drawable/ic_plus_24dp"
-        />
+        app:layout_anchor="@id/filtersView"
+        app:layout_anchorGravity="bottom|end" />
 
 
 </androidx.coordinatorlayout.widget.CoordinatorLayout>