chore(mvvm): CreateCategoryActivity ViewModel

app/build.gradle.kts

@@ -48,6 +48,7 @@ dependencies {
     androidTestImplementation(libs.androidx.junit)
     androidTestImplementation(libs.androidx.espresso.core)
 
+    implementation("androidx.lifecycle:lifecycle-viewmodel-ktx:2.6.1")
     implementation("androidx.core:core-splashscreen:1.0.1")
     implementation("com.squareup.retrofit2:retrofit:2.11.0")
     implementation("com.squareup.retrofit2:converter-gson:2.11.0")

app/src/main/java/com/p_vacho/neat_calendar/activities/CategoriesActivity.kt

@@ -18,6 +18,7 @@ import com.p_vacho.neat_calendar.R
 import com.p_vacho.neat_calendar.adapters.CategoryAdapter
 import com.p_vacho.neat_calendar.api.RetrofitClient
 import com.p_vacho.neat_calendar.api.models.CategoryResponse
+import com.p_vacho.neat_calendar.viewmodels.CategoryMode
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import kotlinx.coroutines.withContext

app/src/main/java/com/p_vacho/neat_calendar/activities/CreateCategoryActivity.kt

@@ -2,42 +2,24 @@ package com.p_vacho.neat_calendar.activities
 
 import android.content.Intent
 import android.content.res.ColorStateList
-import android.graphics.Color
 import android.os.Bundle
-import android.util.Log
 import android.widget.Toast
-import androidx.activity.enableEdgeToEdge
+import androidx.activity.viewModels
 import androidx.appcompat.app.AppCompatActivity
-import androidx.core.content.ContextCompat
+import androidx.core.widget.addTextChangedListener
-import androidx.core.view.ViewCompat
-import androidx.core.view.WindowInsetsCompat
 import androidx.lifecycle.lifecycleScope
 import com.github.dhaval2404.colorpicker.ColorPickerDialog
 import com.google.android.material.button.MaterialButton
 import com.google.android.material.textfield.TextInputEditText
-import com.google.gson.Gson
 import com.p_vacho.neat_calendar.R
-import com.p_vacho.neat_calendar.api.RetrofitClient
-import com.p_vacho.neat_calendar.api.models.CategoryRequest
 import com.p_vacho.neat_calendar.api.models.CategoryResponse
-import com.p_vacho.neat_calendar.api.models.PartialCategoryRequest
+import com.p_vacho.neat_calendar.viewmodels.CategoryMode
-import com.p_vacho.neat_calendar.api.models.ValidationError
+import com.p_vacho.neat_calendar.viewmodels.CreateCategoryViewModel
-import kotlinx.coroutines.Dispatchers
-import kotlinx.coroutines.launch
-import kotlinx.coroutines.withContext
-import retrofit2.HttpException
-import kotlin.properties.Delegates
-
-enum class CategoryMode {
-    CREATE, EDIT
-}
 
 class CreateCategoryActivity : AppCompatActivity() {
-    private var selectedColor by Delegates.notNull<Int>()
+    private val viewModel: CreateCategoryViewModel by viewModels()
-    private var existingCategory: CategoryResponse? = null
+
-    private lateinit var mode: CategoryMode
 
-    // UI components
     private lateinit var etCategoryName: TextInputEditText
     private lateinit var btnColorPicker: MaterialButton
     private lateinit var btnSaveCategory: MaterialButton
@@ -45,114 +27,72 @@ class CreateCategoryActivity : AppCompatActivity() {
 
     override fun onCreate(savedInstanceState: Bundle?) {
         super.onCreate(savedInstanceState)
-        enableEdgeToEdge()
         setContentView(R.layout.activity_create_category)
-        ViewCompat.setOnApplyWindowInsetsListener(findViewById(R.id.main)) { v, insets ->
-            val systemBars = insets.getInsets(WindowInsetsCompat.Type.systemBars())
-            v.setPadding(systemBars.left, systemBars.top, systemBars.right, systemBars.bottom)
-            insets
-        }
 
-        initializeViews()
+        val mode = intent.getStringExtra("mode")?.let { CategoryMode.valueOf(it) } ?: CategoryMode.CREATE
-        mode = intent.getStringExtra("mode")!!.let { CategoryMode.valueOf(it) }
-
-        if (mode == CategoryMode.EDIT) {
         @Suppress("DEPRECATION")
-            existingCategory = intent.getParcelableExtra("category")!!
+        val category = intent.getParcelableExtra<CategoryResponse>("category")
 
-            etCategoryName.setText(existingCategory?.name)
+        initializeViews(mode)
-            selectedColor = existingCategory?.color?.toArgb() ?: ContextCompat.getColor(this, R.color.category_indicator_color)
+        viewModel.initialize(mode, category)
-            btnSaveCategory.setText(R.string.update_category)
+        setupObservers()
-        } else {
-            selectedColor = ContextCompat.getColor(this, R.color.category_indicator_color)
-        }
-
-        btnColorPicker.iconTint = ColorStateList.valueOf(selectedColor)
         setupListeners()
     }
 
-    private fun initializeViews() {
+    private fun initializeViews(mode: CategoryMode) {
         etCategoryName = findViewById(R.id.etCategoryName)
         btnColorPicker = findViewById(R.id.btnColorPicker)
         btnSaveCategory = findViewById(R.id.btnSaveCategory)
         btnCancel = findViewById(R.id.btnCancel)
+
+        if (mode == CategoryMode.EDIT) {
+            btnSaveCategory.setText(R.string.update_category)
+        }
+    }
+
+    private fun setupObservers() {
+        lifecycleScope.launchWhenStarted {
+            viewModel.state.collect { state ->
+                // Only update the text if it's different to avoid overwriting user input
+                if (etCategoryName.text?.toString() != state.categoryName) {
+                    etCategoryName.setText(state.categoryName)
+                }
+
+                btnColorPicker.iconTint = ColorStateList.valueOf(state.selectedColor)
+
+                if (state.errorMessage != null) {
+                    Toast.makeText(this@CreateCategoryActivity, state.errorMessage, Toast.LENGTH_SHORT).show()
+                }
+
+                // Handle successful category save
+                state.successCategory?.let { category ->
+                    val intent = Intent().apply {
+                        if (state.isCreateMode) {
+                            putExtra("newCategory", category)
+                        } else {
+                            putExtra("editedCategory", category)
+                        }
+                    }
+                    setResult(RESULT_OK, intent)
+                    finish() // Finish activity and return the result
+                }
+            }
+        }
     }
 
     private fun setupListeners() {
         btnColorPicker.setOnClickListener { openColorPickerDialog() }
-        btnSaveCategory.setOnClickListener { saveCategory() }
+        etCategoryName.addTextChangedListener { viewModel.onCategoryNameChanged(it.toString()) }
+        btnSaveCategory.setOnClickListener { viewModel.saveCategory() }
         btnCancel.setOnClickListener { finish() }
     }
 
-    private fun saveCategory() {
-        val categoryName = etCategoryName.text.toString().trim()
-        if (categoryName.isEmpty()) {
-            Toast.makeText(this, getString(R.string.please_enter_a_category_name), Toast.LENGTH_SHORT).show()
-            return
-        }
-
-        lifecycleScope.launch(Dispatchers.IO) {
-            try {
-                val resultCategory = if (mode == CategoryMode.CREATE) {
-                    val request =
-                        CategoryRequest(name = categoryName, color = Color.valueOf(selectedColor))
-                    RetrofitClient.categoryService.createCategory(request)
-                } else {
-                    val request = PartialCategoryRequest(
-                        name = categoryName.takeIf { it != existingCategory?.name },
-                        color = Color.valueOf(selectedColor)
-                            .takeIf { it != existingCategory?.color }
-                    )
-                    RetrofitClient.categoryService.updateCategory(existingCategory!!.id, request)
-                }
-
-                withContext(Dispatchers.Main) { handleCategorySaved(resultCategory) }
-            } catch (e: HttpException) {
-                if (e.code() != 422) {
-                    throw e
-                }
-
-                val errorBody = e.response()?.errorBody()?.string()
-                val validationError = Gson().fromJson(errorBody, ValidationError::class.java)
-                val errMsg = validationError.detail.joinToString("\n")
-
-                Log.e("CategoryCreate", "Got HTTP 422: $validationError")
-
-                withContext(Dispatchers.Main) {
-                    Toast.makeText(
-                        this@CreateCategoryActivity,
-                        getString(R.string.failed_to_save_category, errMsg),
-                        Toast.LENGTH_SHORT
-                    ).show()
-                }
-            }
-        }
-    }
-
-    private fun handleCategorySaved(category: CategoryResponse) {
-        Log.w("CreateCategory", "Ending")
-        val intent = Intent().apply {
-            if (mode == CategoryMode.CREATE) {
-                putExtra("newCategory", category)
-                Log.w("CreateCategory", "New")
-            } else {
-                putExtra("editedCategory", category)
-                Log.w("CreateCategory", "Edit")
-            }
-        }
-        setResult(RESULT_OK, intent)
-        finish()
-    }
-
     private fun openColorPickerDialog() {
         ColorPickerDialog
             .Builder(this)
             .setTitle(getString(R.string.select_color))
-            .setDefaultColor(selectedColor)
+            .setDefaultColor(viewModel.state.value.selectedColor)
-            .setColorListener { color, _ ->
+            .setColorListener { color, _ -> viewModel.onColorSelected(color) }
-                selectedColor = color
-                btnColorPicker.iconTint = ColorStateList.valueOf(color)
-            }
             .show()
     }
 }

app/src/main/java/com/p_vacho/neat_calendar/viewmodels/CreateCategoryViewModel.kt

@@ -0,0 +1,109 @@
+package com.p_vacho.neat_calendar.viewmodels
+
+import android.app.Application
+import android.graphics.Color
+import android.util.Log
+import androidx.lifecycle.AndroidViewModel
+import androidx.lifecycle.viewModelScope
+import com.google.gson.Gson
+import com.p_vacho.neat_calendar.R
+import com.p_vacho.neat_calendar.api.RetrofitClient
+import com.p_vacho.neat_calendar.api.models.CategoryRequest
+import com.p_vacho.neat_calendar.api.models.CategoryResponse
+import com.p_vacho.neat_calendar.api.models.PartialCategoryRequest
+import com.p_vacho.neat_calendar.api.models.ValidationError
+import kotlinx.coroutines.flow.MutableStateFlow
+import kotlinx.coroutines.flow.asStateFlow
+import kotlinx.coroutines.launch
+import retrofit2.HttpException
+
+enum class CategoryMode {
+    CREATE, EDIT
+}
+
+data class CreateCategoryState(
+    val categoryName: String = "",
+    val selectedColor: Int = Color.GRAY,
+    val isLoading: Boolean = false,
+    val errorMessage: String? = null,
+    val successCategory: CategoryResponse? = null,
+    val isCreateMode: Boolean = true,
+)
+
+class CreateCategoryViewModel(application: Application) : AndroidViewModel(application) {
+    private val _state = MutableStateFlow(CreateCategoryState())
+    val state = _state.asStateFlow()
+
+    private var existingCategory: CategoryResponse? = null
+
+    fun initialize(mode: CategoryMode, category: CategoryResponse?) {
+        _state.value = _state.value.copy(
+            categoryName = category?.name.orEmpty(),
+            selectedColor = category?.color?.toArgb()
+                ?: getApplication<Application>().getColor(R.color.category_indicator_color),
+            isCreateMode = mode == CategoryMode.CREATE
+        )
+        existingCategory = category
+    }
+
+    fun onCategoryNameChanged(name: String) {
+        if (name != _state.value.categoryName) {
+            _state.value = _state.value.copy(categoryName = name)
+        }
+    }
+
+    fun onColorSelected(color: Int) {
+        if (color != _state.value.selectedColor) {
+            _state.value = _state.value.copy(selectedColor = color)
+        }
+    }
+
+    fun saveCategory() {
+        val categoryName = _state.value.categoryName.trim()
+        if (categoryName.isEmpty()) {
+            _state.value = _state.value.copy(
+                errorMessage = getApplication<Application>().getString(
+                    R.string.please_enter_a_category_name
+                )
+            )
+            return
+        }
+
+        _state.value = _state.value.copy(isLoading = true, errorMessage = null)
+
+        viewModelScope.launch {
+            try {
+                val resultCategory = if (_state.value.isCreateMode) {
+                    val request = CategoryRequest(
+                        name = categoryName,
+                        color = Color.valueOf(_state.value.selectedColor)
+                    )
+                    RetrofitClient.categoryService.createCategory(request)
+                } else {
+                    existingCategory?.let { category ->
+                        val request = PartialCategoryRequest(
+                            name = categoryName.takeIf { it != category.name },
+                            color = Color.valueOf(_state.value.selectedColor).takeIf { it != category.color }
+                        )
+                        RetrofitClient.categoryService.updateCategory(category.id, request)
+                    } ?: throw IllegalStateException("Category is required for EDIT mode")
+                }
+
+                _state.value = _state.value.copy(successCategory = resultCategory)
+            } catch (e: HttpException) {
+                if (e.code() != 422) throw e
+                val errorBody = e.response()?.errorBody()?.string()
+                val validationError = Gson().fromJson(errorBody, ValidationError::class.java)
+                val errMsg = validationError.detail.joinToString("\n")
+
+                Log.e("CategoryCreate", "Got HTTP 422: $validationError")
+
+                _state.value = _state.value.copy(
+                    errorMessage = getApplication<Application>().getString(R.string.failed_to_save_category, errMsg)
+                )
+            } finally {
+                _state.value = _state.value.copy(isLoading = false)
+            }
+        }
+    }
+}