added ability to cancel changes in bool preference as well (was alrea…

…dy possible elsewhere) as well as in the KotPreference versions

demo/src/main/java/com/michaelflisar/composepreferences/demo/classes/Demo2Prefs.kt

@@ -8,6 +8,7 @@ object Demo2Prefs : SettingsModel(DataStoreStorage(name = "demo2_prefs")) {
     // demo preferences
     val stringValue by stringPref("some string")
     val intValue by intPref(123)
+    val boolValue by boolPref(true)
 
     // master/node example
     val master1 by boolPref(true)

demo/src/main/java/com/michaelflisar/composepreferences/demo/demos/PrefScreenDemo.kt

@@ -185,6 +185,7 @@ private fun PreferenceScope.PreferenceInfoExamples() {
 private fun PreferenceScope.PreferenceBoolExamples() {
     val dataStore = LocalDataStore.current
     val scope = rememberCoroutineScope()
+    val context = LocalContext.current
     DemoPreferenceGroup(
         type = "Bool",
         details = "Click to see some switch/checkbox preference examples",
@@ -256,6 +257,22 @@ private fun PreferenceScope.PreferenceBoolExamples() {
             },
             title = { Text("Bool 5 - No Icon") }
         )
+        // Cancel any change via callbak
+        val bool6 = dataStore.getBool("bool6", true).collectAsState(initial = true)
+        PreferenceBool(
+            style = PreferenceBool.Style.Switch,
+            value = bool6.value,
+            onValueChange = {
+                if (it) {
+                    scope.launch(Dispatchers.IO) {
+                        dataStore.update("bool5", it)
+                    }
+                } else {
+                    ToastHelper.show(context, "Change was rejected!")
+                }
+            },
+            title = { Text("Bool 6 - Can't be changed because onValueChange only accept true") }
+        )
     }
 }
 

demo/src/main/java/com/michaelflisar/composepreferences/demo/demos/PrefScreenDemoKotPreferences.kt

@@ -6,13 +6,14 @@ import androidx.compose.material.icons.filled.Check
 import androidx.compose.material.icons.filled.DoubleArrow
 import androidx.compose.material.icons.filled.Group
 import androidx.compose.material.icons.filled.Numbers
-import androidx.compose.material.icons.filled.TextSnippet
 import androidx.compose.material3.Icon
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
+import androidx.compose.ui.platform.LocalContext
+import com.michaelflisar.composedemobaseactivity.classes.ToastHelper
 import com.michaelflisar.composepreferences.core.PreferenceDivider
-import com.michaelflisar.composepreferences.core.PreferenceSectionHeader
 import com.michaelflisar.composepreferences.core.PreferenceScreen
+import com.michaelflisar.composepreferences.core.PreferenceSectionHeader
 import com.michaelflisar.composepreferences.core.PreferenceSubScreen
 import com.michaelflisar.composepreferences.core.classes.PreferenceSettingsDefaults
 import com.michaelflisar.composepreferences.core.classes.PreferenceStyleDefaults
@@ -26,6 +27,8 @@ import com.michaelflisar.composepreferences.screen.input.PreferenceInputText
 @Composable
 fun PrefScreenDemoKotPreferences1() {
 
+    val context = LocalContext.current
+
     PreferenceScreen(
         // optional settings for this screen...
         settings = PreferenceSettingsDefaults.settings(
@@ -144,5 +147,27 @@ fun PrefScreenDemoKotPreferences1() {
                 )
             }
         }
+
+        // -----------
+        // Cancelable change
+        // -----------
+
+        PreferenceSectionHeader(
+            title = { Text("Reject changes") },
+            visible = Demo2Prefs.master2.asDependency { it }
+        )
+
+        PreferenceBool(
+            style = PreferenceBool.Style.Checkbox,
+            data = Demo2Prefs.boolValue.asPreferenceData() {
+                // we cancel the change and don't allow the user to change this preference this way
+                ToastHelper.show(context, "Change was rejected!")
+                false
+            },
+            visible = Demo2Prefs.master2.asDependency { it },
+            title = { Text("2b) Node") },
+            subtitle = { Text("Sub Item Master2") },
+            icon = { Icon(Icons.Default.Check, null) }
+        )
     }
 }

library/core/src/main/java/com/michaelflisar/composepreferences/core/classes/PreferenceData.kt

@@ -11,7 +11,7 @@ import androidx.compose.runtime.MutableState
  */
 data class PreferenceData<T>(
     val value: T,
-    val onValueChange: (data: T) -> Unit = {}
+    val onValueChange: (data: T) -> Unit
 ) {
     companion object
 }
@@ -21,10 +21,14 @@ data class PreferenceData<T>(
  *
  * @return a [PreferenceData]
  */
-fun <T> MutableState<T>.asPreferenceData(): PreferenceData<T> {
-    return PreferenceData(
-        value
-    ) { value = it }
+fun <T> MutableState<T>.asPreferenceData(
+    onValueChange: (data: T) -> Boolean = { true }
+): PreferenceData<T> {
+    return PreferenceData(value) {
+        if (onValueChange(it)) {
+            value = it
+        }
+    }
 }
 
 //@Composable

library/modules/kotpreferences/src/main/java/com/michaelflisar/composepreferences/kotpreferences/Extensions.kt

@@ -26,15 +26,23 @@ fun <T> StorageSetting<T>.collectSetting(
 }
 
 /**
- simple extension function to plug in a setting as preference data provider and updater
+ * simple extension function to plug in a setting as preference data provider and updater
+ *
+ * @param onValueChange the value changed callback of this item (return true to accept the change, false to cancel it)
  */
 @Composable
-fun <T> StorageSetting<T>.asPreferenceData(): PreferenceData<T> {
+fun <T> StorageSetting<T>.asPreferenceData(
+    onValueChange: (data: T) -> Boolean = { true }
+): PreferenceData<T> {
     val scope = rememberCoroutineScope()
     val state = collectSetting()
-    return PreferenceData(state.value) {
-        scope.launch(Dispatchers.IO) {
-            update(it)
+    return PreferenceData(
+        state.value
+    ) {
+        if (onValueChange(it)) {
+            scope.launch(Dispatchers.IO) {
+                update(it)
+            }
         }
     }
 }

library/modules/screen/bool/src/main/java/com/michaelflisar/composepreferences/screen/bool/PreferenceBool.kt

@@ -89,12 +89,10 @@ fun PreferenceScope.PreferenceBool(
     preferenceStyle: PreferenceStyle = LocalPreferenceSettings.current.itemStyle,
     itemSetup: PreferenceItemSetup = PreferenceBoolDefaults.itemSetup()
 ) {
-    var checked by remember(value) { mutableStateOf(value) }
     val onClick = if (LocalPreferenceSettings.current.toggleBooleanOnItemClick) {
         {
-            val updated = !checked
+            val updated = !value
             onValueChange(updated)
-            checked = updated
         }
     } else null
 
@@ -111,16 +109,14 @@ fun PreferenceScope.PreferenceBool(
     ) {
         when (style) {
             PreferenceBool.Style.Checkbox -> {
-                Checkbox(checked = checked, onCheckedChange = {
+                Checkbox(checked = value, onCheckedChange = {
                     onValueChange(it)
-                    checked = it
                 })
             }
 
             PreferenceBool.Style.Switch -> {
-                Switch(checked = checked, onCheckedChange = {
+                Switch(checked = value, onCheckedChange = {
                     onValueChange(it)
-                    checked = it
                 })
             }
         }