Fix some nullability unwrapping in OverviewViewModel

android/build.gradle

@@ -54,6 +54,9 @@ dependencies {
     implementation "com.google.dagger:dagger:$dagger"
     kapt "com.google.dagger:dagger-compiler:$dagger"
     kapt "com.squareup.moshi:moshi-kotlin-codegen:$moshi"
+
+    implementation 'com.github.PhilJay:MPAndroidChart:v3.1.0'
+
     testImplementation 'junit:junit:4.12'
     androidTestImplementation 'androidx.test:runner:1.3.0'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.3.0'

android/src/main/java/com/wbrawner/budget/ui/overview/OverviewFragment.kt

@@ -6,9 +6,16 @@ import android.util.Log
 import android.view.LayoutInflater
 import android.view.View
 import android.view.ViewGroup
+import androidx.core.content.res.ResourcesCompat
 import androidx.fragment.app.Fragment
 import androidx.fragment.app.viewModels
 import androidx.lifecycle.Observer
+import com.github.mikephil.charting.components.AxisBase
+import com.github.mikephil.charting.components.XAxis
+import com.github.mikephil.charting.data.BarData
+import com.github.mikephil.charting.data.BarDataSet
+import com.github.mikephil.charting.data.BarEntry
+import com.github.mikephil.charting.formatter.ValueFormatter
 import com.wbrawner.budget.AllowanceApplication
 import com.wbrawner.budget.AsyncState
 import com.wbrawner.budget.R
@@ -30,6 +37,24 @@ class OverviewFragment : Fragment() {
     ): View? = inflater.inflate(R.layout.fragment_overview, container, false)
 
     override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
+        expectedActualChart.apply {
+            setFitBars(true)
+            xAxis.valueFormatter = object : ValueFormatter() {
+                override fun getFormattedValue(value: Float): String {
+                    return if (value == 0f) "Income" else "Expenses"
+                }
+
+                override fun getBarLabel(barEntry: BarEntry?): String {
+                    return super.getBarLabel(barEntry)
+                }
+            }
+            xAxis.position = XAxis.XAxisPosition.BOTTOM
+            xAxis.granularity = 1f
+            xAxis.isGranularityEnabled = true
+            setDrawGridBackground(false)
+            axisLeft.axisMinimum = 0f
+            axisRight.axisMinimum = 0f
+        }
         viewModel.state.observe(viewLifecycleOwner, Observer { state ->
             when (state) {
                 is AsyncState.Loading -> {
@@ -43,6 +68,30 @@ class OverviewFragment : Fragment() {
                     progressBar.visibility = View.GONE
                     activity?.title = state.data.budget.name
                     balance.text = state.data.balance.toAmountSpannable(view.context)
+                    val expectedIncome = (state.data.expectedIncome / 100).toFloat()
+                    val expectedExpenses = (state.data.expectedExpenses / 100).toFloat()
+                    val actualIncome = (state.data.actualIncome / 100).toFloat()
+                    val actualExpenses = (state.data.actualExpenses / 100).toFloat()
+                    val max = maxOf(expectedIncome, expectedExpenses, actualIncome, actualExpenses)
+                    expectedActualChart.axisLeft.axisMaximum = max
+                    expectedActualChart.axisRight.axisMaximum = max
+                    expectedActualChart.data = BarData(
+                            BarDataSet(
+                                    listOf(BarEntry(0f, expectedIncome), BarEntry(1f, expectedExpenses)),
+                                    "Expected"
+                            ).apply {
+                                color = ResourcesCompat.getColor(resources, R.color.colorSecondary, requireContext().theme)
+                            },
+                            BarDataSet(
+                                    listOf(BarEntry(0f, actualIncome), BarEntry(1f, actualExpenses)),
+                                    "Actual"
+                            ).apply {
+                                color = ResourcesCompat.getColor(resources, R.color.colorAccent, requireContext().theme)
+                            }
+                    ).apply {
+                        barWidth = 0.25f
+                    }
+                    expectedActualChart.groupBars(0f, 0.06f, 0.01f)
                 }
                 is AsyncState.Error -> {
                     overviewContent.visibility = View.GONE

android/src/main/java/com/wbrawner/budget/ui/overview/OverviewViewModel.kt

@@ -4,6 +4,7 @@ import androidx.lifecycle.*
 import com.wbrawner.budget.AsyncState
 import com.wbrawner.budget.common.budget.Budget
 import com.wbrawner.budget.common.budget.BudgetRepository
+import com.wbrawner.budget.common.category.CategoryRepository
 import com.wbrawner.budget.common.transaction.TransactionRepository
 import kotlinx.coroutines.launch
 import javax.inject.Inject
@@ -14,12 +15,16 @@ class OverviewViewModel : ViewModel() {
     @Inject
     lateinit var budgetRepo: BudgetRepository
 
+    @Inject
+    lateinit var categoryRepo: CategoryRepository
+
     @Inject
     lateinit var transactionRepo: TransactionRepository
 
     fun loadOverview(lifecycleOwner: LifecycleOwner) {
         budgetRepo.currentBudget.observe(lifecycleOwner, Observer { budget ->
-            if (budget == null) {
+            val budgetId = budget?.id
+            if (budgetId == null) {
                 state.postValue(AsyncState.Error("Invalid Budget ID"))
                 return@Observer
             }
@@ -27,9 +32,28 @@ class OverviewViewModel : ViewModel() {
                 state.postValue(AsyncState.Loading)
                 try {
                     // TODO: Load expected and actual income/expense amounts as well
+                    var expectedExpenses = 0L
+                    var expectedIncome = 0L
+                    var actualExpenses = 0L
+                    var actualIncome = 0L
+                    categoryRepo.findAll(arrayOf(budgetId)).forEach { category ->
+                        val categoryId = category.id ?: return@forEach
+                        val balance = categoryRepo.getBalance(categoryId)
+                        if (category.expense) {
+                            expectedExpenses += category.amount
+                            actualExpenses += (balance * -1)
+                        } else {
+                            expectedIncome += category.amount
+                            actualIncome += balance
+                        }
+                    }
                     state.postValue(AsyncState.Success(OverviewState(
                             budget,
-                            budgetRepo.getBalance(budget.id!!)
+                            budgetRepo.getBalance(budgetId),
+                            expectedIncome,
+                            expectedExpenses,
+                            actualIncome,
+                            actualExpenses
                     )))
                 } catch (e: Exception) {
                     state.postValue(AsyncState.Error(e))
@@ -41,5 +65,9 @@ class OverviewViewModel : ViewModel() {
 
 data class OverviewState(
         val budget: Budget,
-        val balance: Long
+        val balance: Long,
+        val expectedIncome: Long,
+        val expectedExpenses: Long,
+        val actualIncome: Long,
+        val actualExpenses: Long,
 )

android/src/main/res/layout/fragment_overview.xml

@@ -1,15 +1,22 @@
 <?xml version="1.0" encoding="utf-8"?>
-<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
+<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
-    android:layout_height="match_parent">
+    android:layout_height="match_parent"
+    android:fillViewport="true">
+
+    <FrameLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center">
 
         <LinearLayout
             android:id="@+id/overviewContent"
-        android:orientation="vertical"
-        android:gravity="center"
             android:layout_width="match_parent"
-        android:layout_height="match_parent">
+            android:layout_height="wrap_content"
+            android:layout_gravity="center"
+            android:gravity="center"
+            android:orientation="vertical">
 
             <TextView
                 android:id="@+id/balanceLabel"
@@ -25,6 +32,11 @@
                 android:layout_margin="8dp"
                 android:textSize="36sp" />
 
+            <com.github.mikephil.charting.charts.HorizontalBarChart
+                android:id="@+id/expectedActualChart"
+                android:layout_width="match_parent"
+                android:layout_height="200dp" />
+
         </LinearLayout>
 
         <androidx.emoji.widget.EmojiTextView
@@ -47,4 +59,6 @@
             android:layout_gravity="center"
             android:visibility="gone"
             tools:visibility="visible" />
+
     </FrameLayout>
+</ScrollView>

android/src/main/res/values/colors.xml

@@ -8,4 +8,5 @@
     <color name="colorTextGreen">#388e3c</color>
     <color name="colorTextRed">#d32f2f</color>
     <color name="colorTextPrimaryInverted">#FFDADADA</color>
+    <color name="colorSecondary">#888888</color>
 </resources>