Merge pull request #24 from cbess/observer-notifications

Add observer notifications and update demo app.
cbess · Aug 16, 2013 · 2969c00 · 2969c00
2 parents ebec5cb + 004b173
commit 2969c00
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Showing 4 changed files with 57 additions and 11 deletions.
diff --git a/AutoScrollLabelDemo/AutoScrollLabelDemo/ASLViewController.m b/AutoScrollLabelDemo/AutoScrollLabelDemo/ASLViewController.m
@@ -24,22 +24,24 @@ - (void)viewDidLoad
     [super viewDidLoad];
 
     // setup the auto scroll label
-    self.autoScrollLabel.text = @"This text may be clipped, but now it will be scrolled.";
+    self.autoScrollLabel.text = @"This text may be clipped, but now it will be scrolled. This text will be scrolled even after device rotation.";
     self.autoScrollLabel.textColor = [UIColor blueColor];
     self.autoScrollLabel.labelSpacing = 35; // distance between start and end labels
     self.autoScrollLabel.pauseInterval = 1.7; // seconds of pause before scrolling starts again
     self.autoScrollLabel.scrollSpeed = 30; // pixels per second
     self.autoScrollLabel.textAlignment = NSTextAlignmentCenter; // centers text when no auto-scrolling is applied
     self.autoScrollLabel.fadeLength = 12.f;
     self.autoScrollLabel.scrollDirection = CBAutoScrollDirectionLeft;
+    [self.autoScrollLabel observeApplicationNotifications];
 
     // navigation bar auto scroll label
-    self.navigationBarScrollLabel.text = @"Navigation Bar Title... Scrolling.";
+    self.navigationBarScrollLabel.text = @"Navigation Bar Title... Scrolling... And scrolling.";
     self.navigationBarScrollLabel.pauseInterval = 3.f;
     self.navigationBarScrollLabel.font = [UIFont boldSystemFontOfSize:20];
     self.navigationBarScrollLabel.textColor = [UIColor whiteColor];
     self.navigationBarScrollLabel.shadowOffset = CGSizeMake(-1, -1);
     self.navigationBarScrollLabel.shadowColor = [UIColor blackColor];
+    [self.navigationBarScrollLabel observeApplicationNotifications];
 }
 
 @end
diff --git a/AutoScrollLabelDemo/AutoScrollLabelDemo/en.lproj/ASLViewController.xib b/AutoScrollLabelDemo/AutoScrollLabelDemo/en.lproj/ASLViewController.xib
@@ -40,7 +40,7 @@
 				<array class="NSMutableArray" key="NSSubviews">
 					<object class="IBUILabel" id="84194377">
 						<reference key="NSNextResponder" ref="774585933"/>
-						<int key="NSvFlags">292</int>
+						<int key="NSvFlags">293</int>
 						<string key="NSFrame">{{20, 196}, {280, 21}}</string>
 						<reference key="NSSuperview" ref="774585933"/>
 						<reference key="NSWindow"/>
@@ -73,7 +73,7 @@
 					</object>
 					<object class="IBUIView" id="375038343">
 						<reference key="NSNextResponder" ref="774585933"/>
-						<int key="NSvFlags">292</int>
+						<int key="NSvFlags">290</int>
 						<array class="NSMutableArray" key="NSSubviews"/>
 						<string key="NSFrame">{{20, 105}, {280, 42}}</string>
 						<reference key="NSSuperview" ref="774585933"/>
@@ -95,7 +95,7 @@
 						<array class="NSMutableArray" key="NSSubviews">
 							<object class="IBUIView" id="295045083">
 								<reference key="NSNextResponder" ref="76686105"/>
-								<int key="NSvFlags">292</int>
+								<int key="NSvFlags">290</int>
 								<array class="NSMutableArray" key="NSSubviews"/>
 								<string key="NSFrame">{{75, 6}, {170, 33}}</string>
 								<reference key="NSSuperview" ref="76686105"/>

diff --git a/CBAutoScrollLabel/CBAutoScrollLabel.h b/CBAutoScrollLabel/CBAutoScrollLabel.h
@@ -62,4 +62,12 @@ typedef enum  {
  * Initiates auto-scroll if the label width exceeds the bounds of the scrollview.
  */
 - (void)scrollLabelIfNeeded;
+
+/**
+ * Observes UIApplication state notifications to auto-restart scrolling and watch for 
+ * orientation changes to refresh the labels.
+ * @discussion Must be called to observe the notifications. Calling multiple times will still only
+ * register the notifications once.
+ */
+- (void)observeApplicationNotifications;
 @end
diff --git a/CBAutoScrollLabel/CBAutoScrollLabel.m b/CBAutoScrollLabel/CBAutoScrollLabel.m
@@ -115,7 +115,9 @@ - (void)commonInit
 - (void)dealloc 
 {
     self.labels = nil;
-    [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(enableShadow) object:nil];
+    [NSObject cancelPreviousPerformRequestsWithTarget:self];
+    [[NSNotificationCenter defaultCenter] removeObserver:self];
+
     #if ! __has_feature(objc_arc)
     [super dealloc];
     #endif
@@ -267,6 +269,28 @@ - (CGSize)shadowOffset
 
 #pragma mark - Misc
 
+- (void)observeApplicationNotifications
+{
+    [[NSNotificationCenter defaultCenter] removeObserver:self];
+
+    // restart scrolling when the app has been activated
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(scrollLabelIfNeeded)
+                                                 name:UIApplicationWillEnterForegroundNotification
+                                               object:nil];
+
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(scrollLabelIfNeeded)
+                                                 name:UIApplicationDidBecomeActiveNotification
+                                               object:nil];
+
+    // refresh labels when interface orientation is changed
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(onUIApplicationDidChangeStatusBarOrientationNotification:)
+                                                 name:UIApplicationDidChangeStatusBarOrientationNotification
+                                               object:nil];
+}
+
 - (void)enableShadow
 {
     _scrolling = YES;
@@ -312,7 +336,7 @@ - (void)scrollLabelIfNeeded
 
 - (void)refreshLabels
 {
-	__block float offset = 0.0;
+	__block float offset = 0;
 
     // calculate the label size
     CGSize labelSize = [self.mainLabel.text sizeWithFont:self.mainLabel.font
@@ -322,7 +346,7 @@ - (void)refreshLabels
         CGRect frame = label.frame;
         frame.origin.x = offset;
         frame.size.height = CGRectGetHeight(self.bounds);
-        frame.size.width = labelSize.width + 2 /*Magic number*/;
+        frame.size.width = labelSize.width + 2.f /*Magic number*/;
         label.frame = frame;
 
         // Recenter label vertically within the scroll view
@@ -369,7 +393,7 @@ - (void)applyGradientMaskForFadeLength:(CGFloat)fadeLength enableFade:(BOOL)fade
 {
     CGFloat labelWidth = CGRectGetWidth(self.mainLabel.bounds);
 	if (labelWidth <= CGRectGetWidth(self.bounds))
-        fadeLength = 0.0;
+        fadeLength = 0;
 
     if (fadeLength)
     {
@@ -382,8 +406,8 @@ - (void)applyGradientMaskForFadeLength:(CGFloat)fadeLength enableFade:(BOOL)fade
         gradientMask.shouldRasterize = YES;
         gradientMask.rasterizationScale = [UIScreen mainScreen].scale;
 
-        gradientMask.startPoint = CGPointMake(0.0, CGRectGetMidY(self.frame));
-        gradientMask.endPoint = CGPointMake(1.0, CGRectGetMidY(self.frame));
+        gradientMask.startPoint = CGPointMake(0, CGRectGetMidY(self.frame));
+        gradientMask.endPoint = CGPointMake(1, CGRectGetMidY(self.frame));
 
         // setup fade mask colors and location
         id transparent = (id)[UIColor clearColor].CGColor;
@@ -409,7 +433,10 @@ - (void)applyGradientMaskForFadeLength:(CGFloat)fadeLength enableFade:(BOOL)fade
         // apply calculations to mask
         gradientMask.locations = @[@0, leftFadePoint, rightFadePoint, @1];
 
+        [CATransaction begin];
+        [CATransaction setDisableActions:YES];
         self.layer.mask = gradientMask;
+        [CATransaction commit];
     }
     else
     {
@@ -418,4 +445,13 @@ - (void)applyGradientMaskForFadeLength:(CGFloat)fadeLength enableFade:(BOOL)fade
     }
 }
 
+#pragma mark - Notifications
+
+- (void)onUIApplicationDidChangeStatusBarOrientationNotification:(NSNotification *)notification
+{
+    // delay to have it re-calculate on next runloop
+    [self performSelector:@selector(refreshLabels) withObject:nil afterDelay:.1f];
+    [self performSelector:@selector(scrollLabelIfNeeded) withObject:nil afterDelay:.1f];
+}
+
 @end