fix behavior when a task has been previously loaded, add an option ShowRefresherFromChildrenStrategy for the CompositeTaskLoader

Author: roubachof

Sharpnado.TaskLoaderView/CompositeTaskLoaderNotifier.cs

@@ -10,16 +10,19 @@
 
 namespace Sharpnado.Presentation.Forms
 {
-    public enum CompositionAutoResetCondition
+    public enum ShowRefresherFromChildrenStrategy
     {
-        AnyCompleted = 0,
-        AllCompleted,
+        Never = 0,
+        WhenAll,
+        WhenAny,
     }
 
     public class CompositeTaskLoaderNotifier : ITaskLoaderNotifier
     {
         protected const string Tag = "CompositeNotifier";
 
+        private readonly ShowRefresherFromChildrenStrategy _showRefresherFromChildrenStrategy;
+
         private readonly ITaskLoaderNotifier[] _loaders;
 
         private bool _showLoader;
@@ -35,9 +38,16 @@ public class CompositeTaskLoaderNotifier : ITaskLoaderNotifier
 
         private Exception _lastError;
 
+        public CompositeTaskLoaderNotifier(params ITaskLoaderNotifier[] taskLoaderNotifiers)
+            : this(ShowRefresherFromChildrenStrategy.Never, taskLoaderNotifiers)
+        {
+        }
+
         public CompositeTaskLoaderNotifier(
+            ShowRefresherFromChildrenStrategy showRefresherFromChildrenStrategy,
             params ITaskLoaderNotifier[] taskLoaderNotifiers)
         {
+            _showRefresherFromChildrenStrategy = showRefresherFromChildrenStrategy;
             _loaders = taskLoaderNotifiers;
 
             Subscribe();
@@ -169,6 +179,11 @@ public Exception LastError
 
         public TimeSpan AutoResetDelay { get; } = TimeSpan.Zero;
 
+        public void OnTaskOverloaded()
+        {
+            InternalLogger.Debug(Tag, () => $"OnTaskOverloaded() : let the child tasks handle their states");
+        }
+
         public void Load(bool isRefreshing = false)
         {
             InternalLogger.Debug(Tag, () => $"Load()");
@@ -262,7 +277,16 @@ private void LoaderOnPropertyChanged(object sender, PropertyChangedEventArgs e)
                     break;
 
                 case nameof(ShowRefresher):
-                    ShowRefresher = _loaders.Any(l => l.ShowRefresher);
+                    switch (_showRefresherFromChildrenStrategy)
+                    {
+                        case ShowRefresherFromChildrenStrategy.WhenAny:
+                            ShowLoader = _loaders.Any(l => l.ShowLoader);
+                            break;
+                        case ShowRefresherFromChildrenStrategy.WhenAll:
+                            ShowLoader = _loaders.All(l => l.ShowLoader);
+                            break;
+                    }
+
                     break;
 
                 case nameof(ShowResult):

Sharpnado.TaskLoaderView/ITaskLoaderNotifier.cs

@@ -50,5 +50,7 @@ public interface ITaskLoaderNotifier : INotifyPropertyChanged
         void Load(bool isRefreshing = false);
 
         void Reset();
+
+        void OnTaskOverloaded();
     }
 }

Sharpnado.TaskLoaderView/NotStartedTaskLoaderNotifier.cs

@@ -68,6 +68,10 @@ public void Reset()
         {
         }
 
+        public void OnTaskOverloaded()
+        {
+        }
+
         private static void DoNothing()
         {
         }

Sharpnado.TaskLoaderView/TaskLoaderNotifier.cs

@@ -32,6 +32,12 @@ public TaskLoaderNotifier(TimeSpan autoResetDelay, Func<bool, Task> loadingTaskS
 
         public override bool IsNotStarted => CurrentLoadingTask == TaskMonitor.NotStartedTask;
 
+        public void UpdateLoadingTaskSource(Func<bool, Task> loadingTaskSource)
+        {
+            InternalLogger.Debug(Tag, () => $"UpdateLoadingTaskSource()");
+            _loadingTaskSource = loadingTaskSource;
+        }
+
         /// <summary>
         /// Load a task previously set.
         /// </summary>
@@ -49,7 +55,7 @@ public void Load(Func<bool, Task> loadingTaskSource, bool isRefreshing = false)
                 if (CurrentLoadingTask != TaskMonitor.NotStartedTask && CurrentLoadingTask.IsNotCompleted)
                 {
                     InternalLogger.Warn("A loading task is currently running: discarding previous call");
-                    Reset();
+                    OnTaskOverloaded();
                     return;
                 }
 

Sharpnado.TaskLoaderView/TaskLoaderNotifierBase.cs

@@ -186,6 +186,20 @@ public virtual void Reset()
             RaisePropertyChanged(nameof(IsFaulted));
         }
 
+        /// <summary>
+        /// We'll need to just cancel the current task and keep all the states cause a new task will be loaded 
+        /// </summary>
+        public void OnTaskOverloaded()
+        {
+            lock (SyncRoot)
+            {
+                if (!IsNotStarted)
+                {
+                    CurrentLoadingTask?.CancelCallbacks();
+                }
+            }
+        }
+
         public override string ToString()
         {
             var builder = new StringBuilder($"{Tag} => ");

Sharpnado.TaskLoaderView/TaskLoaderNotifier{T}.cs

@@ -61,6 +61,12 @@ public override void Load(bool isRefreshing = false)
             Load(_loadingTaskSource, isRefreshing);
         }
 
+        public void UpdateLoadingTaskSource(Func<bool, Task<TData>> loadingTaskSource)
+        {
+            InternalLogger.Debug(Tag, () => $"UpdateLoadingTaskSource()");
+            _loadingTaskSource = loadingTaskSource;
+        }
+
         public void Load(Func<bool, Task<TData>> loadingTaskSource, bool isRefreshing = false)
         {
             InternalLogger.Debug(Tag, () => $"Load( isRefreshing: {isRefreshing} )");
@@ -69,7 +75,7 @@ public void Load(Func<bool, Task<TData>> loadingTaskSource, bool isRefreshing =
                 if (CurrentLoadingTask != TaskMonitor<TData>.NotStartedTask && CurrentLoadingTask.IsNotCompleted)
                 {
                     InternalLogger.Warn("A loading task is currently running: discarding previous call");
-                    Reset();
+                    OnTaskOverloaded();
                 }
 
                 if (CurrentLoadingTask == TaskMonitor<TData>.NotStartedTask && loadingTaskSource == null)