Added an option to execute JUCEApplication's suspend() method on an iOS background task to give you extra time to save your app's state

modules/juce_events/juce_events.h

@@ -57,6 +57,15 @@
 
 #include <juce_core/juce_core.h>
 
+//==============================================================================
+/** Config: JUCE_EXECUTE_APP_SUSPEND_ON_IOS_BACKGROUND_TASK
+    Will execute your application's suspend method on an iOS background task, giving
+    you extra time to save your applications state.
+*/
+#ifndef JUCE_EXECUTE_APP_SUSPEND_ON_BACKGROUND_TASK
+ #define JUCE_EXECUTE_APP_SUSPEND_ON_BACKGROUND_TASK 0
+#endif
+
 #if JUCE_EVENTS_INCLUDE_WINRT_WRAPPER && JUCE_WINDOWS
  #include <hstring.h>
 #endif

modules/juce_gui_basics/native/juce_ios_Windowing.mm

@@ -37,9 +37,11 @@ Array<AppInactivityCallback*> appBecomingInactiveCallbacks;
 
 @interface JuceAppStartupDelegate : NSObject <UIApplicationDelegate>
 {
+    UIBackgroundTaskIdentifier appSuspendTask;
 }
 
 @property (strong, nonatomic) UIWindow *window;
+- (id)init;
 - (void) applicationDidFinishLaunching: (UIApplication*) application;
 - (void) applicationWillTerminate: (UIApplication*) application;
 - (void) applicationDidEnterBackground: (UIApplication*) application;
@@ -52,6 +54,14 @@ Array<AppInactivityCallback*> appBecomingInactiveCallbacks;
 
 @implementation JuceAppStartupDelegate
 
+- (id)init
+{
+    self = [super init];
+    appSuspendTask = UIBackgroundTaskInvalid;
+
+    return self;
+}
+
 - (void) applicationDidFinishLaunching: (UIApplication*) application
 {
     ignoreUnused (application);
@@ -76,10 +86,31 @@ Array<AppInactivityCallback*> appBecomingInactiveCallbacks;
 
 - (void) applicationDidEnterBackground: (UIApplication*) application
 {
-    ignoreUnused (application);
-
     if (JUCEApplicationBase* const app = JUCEApplicationBase::getInstance())
+    {
+       #if JUCE_EXECUTE_APP_SUSPEND_ON_BACKGROUND_TASK
+        appSuspendTask = [application beginBackgroundTaskWithName:@"JUCE Suspend Task" expirationHandler:^{
+            if (appSuspendTask != UIBackgroundTaskInvalid)
+            {
+                [application endBackgroundTask:appSuspendTask];
+                appSuspendTask = UIBackgroundTaskInvalid;
+            }
+        }];
+
+        MessageManager::callAsync ([self,application,app] ()
+                                   {
+                                       app->suspended();
+                                       if (appSuspendTask != UIBackgroundTaskInvalid)
+                                       {
+                                           [application endBackgroundTask:appSuspendTask];
+                                           appSuspendTask = UIBackgroundTaskInvalid;
+                                       }
+                                   });
+       #else
+        ignoreUnused (application);
         app->suspended();
+       #endif
+    }
 }
 
 - (void) applicationWillEnterForeground: (UIApplication*) application