Prevent double-observers for the idleTimerDisabled value change (#108)

* Add a additional class to wrap observers for the sharedApplication.idleTimerDisabled

* CL & version

* Align wording with other entries

Co-authored-by: creativecreatorormaybenot <creativecreatorormaybenot@gmail.com>

+## 0.5.1
+
+* Resolved a crash on iOS which was caused by 2 observers on idleTimerDisabled.
+
 ## 0.5.0+2
 ## 0.5.0+2
 
 
 * Fixed example app builds on macOS.
 * Fixed example app builds on macOS.

@@ -21,8 +21,8 @@ EXTERNAL SOURCES:
 SPEC CHECKSUMS:
 SPEC CHECKSUMS:
   Flutter: 434fef37c0980e73bb6479ef766c45957d4b510c
   Flutter: 434fef37c0980e73bb6479ef766c45957d4b510c
   integration_test: 5ed24a436eb7ec17b6a13046e9bf7ca4a404e59e
   integration_test: 5ed24a436eb7ec17b6a13046e9bf7ca4a404e59e
-  wakelock: bfc7955c418d0db797614075aabbc58a39ab5107
+  wakelock: d0fc7c864128eac40eba1617cb5264d9c940b46f
 
 
 PODFILE CHECKSUM: 8e679eca47255a8ca8067c4c67aab20e64cb974d
 PODFILE CHECKSUM: 8e679eca47255a8ca8067c4c67aab20e64cb974d
 
 
-COCOAPODS: 1.10.0
+COCOAPODS: 1.10.1

@@ -2,6 +2,6 @@
 <Workspace
 <Workspace
    version = "1.0">
    version = "1.0">
    <FileRef
    <FileRef
-      location = "group:Runner.xcodeproj">
+      location = "self:">
    </FileRef>
    </FileRef>
 </Workspace>
 </Workspace>

+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface IdleTimerDisabledObserver : NSObject
+
+@property BOOL enable;
+
++ (IdleTimerDisabledObserver*)singleInstance;
+
+- (void) beginObserving;
+
+- (void) endObserving;
+
+@end
+
+NS_ASSUME_NONNULL_END

+#import "IdleTimerDisabledObserver.h"
+
+@interface IdleTimerDisabledObserver() {
+  int numObservers;
+}
+
+@end
+
+static void * mKeyPathObserverContextApplicationIsIdleTimerDisabled = &mKeyPathObserverContextApplicationIsIdleTimerDisabled;
+
+@implementation IdleTimerDisabledObserver
+
++ (IdleTimerDisabledObserver*)singleInstance {
+  static IdleTimerDisabledObserver *instance = nil;
+  static dispatch_once_t onceToken;
+  dispatch_once(&onceToken, ^{
+    instance = [[self alloc] init];
+  });
+  return instance;
+}
+
+- (void)beginObserving {
+  if (numObservers == 0) {
+    [UIApplication.sharedApplication addObserver:self
+                                      forKeyPath:@"idleTimerDisabled"
+                                         options:NSKeyValueObservingOptionNew
+                                         context:mKeyPathObserverContextApplicationIsIdleTimerDisabled];
+  }
+  
+  numObservers ++;
+}
+
+- (void)endObserving {
+  numObservers --;
+  
+  if (numObservers == 0) {
+    [UIApplication.sharedApplication removeObserver:self forKeyPath:@"idleTimerDisabled" context:mKeyPathObserverContextApplicationIsIdleTimerDisabled];
+  }
+}
+
+- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
+  if (context == mKeyPathObserverContextApplicationIsIdleTimerDisabled) {
+    if (UIApplication.sharedApplication.idleTimerDisabled != self.enable) {
+      UIApplication.sharedApplication.idleTimerDisabled = self.enable;
+    }
+  } else {
+    [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
+  }
+}
+
+
+@end

 #import "WakelockPlugin.h"
 #import "WakelockPlugin.h"
+#import "IdleTimerDisabledObserver.h"
 #import "messages.h"
 #import "messages.h"
 
 
-static void * mKeyPathObserverContextApplicationIsIdleTimerDisabled = &mKeyPathObserverContextApplicationIsIdleTimerDisabled;
 
 
 @interface WakelockPlugin () <FLTWakelockApi>
 @interface WakelockPlugin () <FLTWakelockApi>
 
 
@@ -13,8 +13,8 @@ static void * mKeyPathObserverContextApplicationIsIdleTimerDisabled = &mKeyPathO
 + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
 + (void)registerWithRegistrar:(NSObject<FlutterPluginRegistrar>*)registrar {
   WakelockPlugin* instance = [[WakelockPlugin alloc] init];
   WakelockPlugin* instance = [[WakelockPlugin alloc] init];
   FLTWakelockApiSetup(registrar.messenger, instance);
   FLTWakelockApiSetup(registrar.messenger, instance);
-    
-  [UIApplication.sharedApplication addObserver:instance forKeyPath:@"idleTimerDisabled" options:NSKeyValueObservingOptionNew context:mKeyPathObserverContextApplicationIsIdleTimerDisabled];
+  
+  [[IdleTimerDisabledObserver singleInstance] beginObserving];
 }
 }
 
 
 - (void)toggle:(FLTToggleMessage*)input error:(FlutterError**)error {
 - (void)toggle:(FLTToggleMessage*)input error:(FlutterError**)error {
@@ -36,18 +36,14 @@ static void * mKeyPathObserverContextApplicationIsIdleTimerDisabled = &mKeyPathO
   return result;
   return result;
 }
 }
 
 
-- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
-  if (context == mKeyPathObserverContextApplicationIsIdleTimerDisabled) {
-    if (UIApplication.sharedApplication.idleTimerDisabled != self.enable) {
-      UIApplication.sharedApplication.idleTimerDisabled = self.enable;
-    }
-  } else {
-    [super observeValueForKeyPath:keyPath ofObject:object change:change context:context];
-  }
+- (void)setEnable:(BOOL)enable {
+  [IdleTimerDisabledObserver singleInstance].enable = enable;
+  
+  _enable = enable;
 }
 }
 
 
 - (void)dealloc {
 - (void)dealloc {
-  [UIApplication.sharedApplication removeObserver:self forKeyPath:@"idleTimerDisabled" context:mKeyPathObserverContextApplicationIsIdleTimerDisabled];
+  [[IdleTimerDisabledObserver singleInstance] endObserving];
 }
 }
 
 
 @end
 @end

@@ -2,7 +2,7 @@ name: wakelock
 description: >-2
 description: >-2
   Plugin that allows you to keep the device screen awake, i.e. prevent the screen from sleeping on
   Plugin that allows you to keep the device screen awake, i.e. prevent the screen from sleeping on
   Android, iOS, macOS, Windows, and web.
   Android, iOS, macOS, Windows, and web.
-version: 0.5.0+2
+version: 0.5.1
 homepage: https://github.com/creativecreatorormaybenot/wakelock/tree/master/wakelock
 homepage: https://github.com/creativecreatorormaybenot/wakelock/tree/master/wakelock
 
 
 environment:
 environment: