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Adds support for pull up from bottom to refresh. #18

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2 changes: 2 additions & 0 deletions PullToRefreshView.h
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ typedef enum {
id<PullToRefreshViewDelegate> delegate;
UIScrollView *scrollView;
PullToRefreshViewState state;
BOOL isBottom;

UILabel *subtitleLabel;
UILabel *statusLabel;
Expand All @@ -58,6 +59,7 @@ typedef enum {
- (void)refreshLastUpdatedDate;

- (id)initWithScrollView:(UIScrollView *)scrollView;
- (id)initWithScrollView:(UIScrollView *)scrollView atBottom:(BOOL)bottom;
- (void)finishedLoading;
- (void)beginLoading;
- (void)containingViewDidUnload;
Expand Down
117 changes: 93 additions & 24 deletions PullToRefreshView.m
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,12 @@ @interface PullToRefreshView (Private)

@property (nonatomic, assign) PullToRefreshViewState state;

- (BOOL)isScrolledToVisible;
- (BOOL)isScrolledToLimit;
- (void)parkVisible;
- (void)handleDragWhileLoading;
- (void)updatePosition;

@end

@implementation PullToRefreshView
Expand All @@ -57,22 +63,27 @@ - (void)showActivity:(BOOL)show animated:(BOOL)animated {
- (void)setImageFlipped:(BOOL)flipped {
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:kPullToRefreshViewAnimationDuration];
arrowImage.transform = (flipped ? CATransform3DMakeRotation(M_PI * 2, 0.0f, 0.0f, 1.0f) : CATransform3DMakeRotation(M_PI, 0.0f, 0.0f, 1.0f));
arrowImage.transform = (flipped ^ isBottom ? CATransform3DMakeRotation(M_PI * 2, 0.0f, 0.0f, 1.0f) : CATransform3DMakeRotation(M_PI, 0.0f, 0.0f, 1.0f));
[UIView commitAnimations];
}

- (id)initWithScrollView:(UIScrollView *)scroll {
CGRect frame = CGRectMake(0.0f, 0.0f - scroll.bounds.size.height, scroll.bounds.size.width, scroll.bounds.size.height);
- (id)initWithScrollView:(UIScrollView *)scroll atBottom:(BOOL)bottom {
CGFloat bottomOffset = (scroll.contentSize.height < scroll.bounds.size.height) ? scroll.bounds.size.height : scroll.contentSize.height;
CGFloat offset = bottom ? bottomOffset : 0.0f - scroll.bounds.size.height;
CGRect frame = CGRectMake(0.0f, offset, scroll.bounds.size.width, scroll.bounds.size.height);

if ((self = [super initWithFrame:frame])) {
CGFloat visibleBottom = bottom ? -kPullToRefreshViewTriggerOffset : self.frame.size.height;
isBottom = bottom;
scrollView = [scroll retain];
[scrollView addObserver:self forKeyPath:@"contentOffset" options:NSKeyValueObservingOptionNew context:NULL];
[scrollView addObserver:self forKeyPath:@"contentSize" options:NSKeyValueObservingOptionNew context:NULL];

self.autoresizingMask = UIViewAutoresizingFlexibleWidth;
self.backgroundColor = kPullToRefreshViewBackgroundColor;

subtitleLabel = [[UILabel alloc] init];
subtitleLabel.frame = CGRectMake(0.0f, frame.size.height - 30.0f, self.frame.size.width, 20.0f);
subtitleLabel.frame = CGRectMake(0.0f, visibleBottom - 30.0f, self.frame.size.width, 20.0f);
subtitleLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth;
subtitleLabel.font = [UIFont systemFontOfSize:12.0f];
subtitleLabel.textColor = kPullToRefreshViewSubtitleColor;
Expand All @@ -82,7 +93,7 @@ - (id)initWithScrollView:(UIScrollView *)scroll {
subtitleLabel.textAlignment = UITextAlignmentCenter;
[self addSubview:subtitleLabel];

statusLabel = [[UILabel alloc] init];
statusLabel = [[UILabel alloc] initWithFrame:CGRectMake(0.0f, visibleBottom - 48.0f, self.frame.size.width, 20.0f)];
statusLabel.autoresizingMask = UIViewAutoresizingFlexibleWidth;
statusLabel.font = [UIFont systemFontOfSize:12.f];
statusLabel.textColor = kPullToRefreshViewTitleColor;
Expand All @@ -93,12 +104,14 @@ - (id)initWithScrollView:(UIScrollView *)scroll {
[self addSubview:statusLabel];

arrowImage = [[CALayer alloc] init];
arrowImage.frame = CGRectMake(25.0f, frame.size.height - 60.0f, 24.0f, 52.0f);
UIImage *arrow = [UIImage imageNamed:@"arrow"];
arrowImage.contents = (id) arrow.CGImage;
arrowImage.frame = CGRectMake(25.0f, visibleBottom + kPullToRefreshViewTriggerOffset + 5.0f, arrow.size.width, arrow.size.height);
arrowImage.contentsGravity = kCAGravityResizeAspect;
arrowImage.contents = (id) [UIImage imageNamed:@"arrow"].CGImage;
[self setImageFlipped:NO];

activityView = [[UIActivityIndicatorView alloc] initWithActivityIndicatorStyle:UIActivityIndicatorViewStyleGray];
activityView.frame = CGRectMake(30.0f, frame.size.height - 38.0f, 20.0f, 20.0f);
activityView.frame = CGRectMake(30.0f, visibleBottom - 38.0f, 20.0f, 20.0f);
[self addSubview:activityView];

#if __IPHONE_OS_VERSION_MAX_ALLOWED >= 40000
Expand All @@ -113,6 +126,10 @@ - (id)initWithScrollView:(UIScrollView *)scroll {
return self;
}

- (id)initWithScrollView:(UIScrollView *)scroll {
return [self initWithScrollView:scroll atBottom:NO];
}

#pragma mark -
#pragma mark Setters

Expand Down Expand Up @@ -152,10 +169,9 @@ - (void)setState:(PullToRefreshViewState)state_ {
statusLabel.text = @"Release to refresh…";
[self showActivity:NO animated:NO];
[self setImageFlipped:YES];
scrollView.contentInset = UIEdgeInsetsZero;
break;
case kPullToRefreshViewStateNormal:
statusLabel.text = @"Pull down to refresh…";
statusLabel.text = [NSString stringWithFormat:@"Pull %@ to refresh...", isBottom ? @"up" : @"down"];
[self showActivity:NO animated:NO];
[self setImageFlipped:NO];
[self refreshLastUpdatedDate];
Expand All @@ -166,7 +182,7 @@ - (void)setState:(PullToRefreshViewState)state_ {
statusLabel.text = @"Loading…";
[self showActivity:YES animated:YES];
[self setImageFlipped:NO];
scrollView.contentInset = UIEdgeInsetsMake(fminf(-scrollView.contentOffset.y, -kPullToRefreshViewTriggerOffset), 0, 0, 0);
[self parkVisible];
break;
default:
break;
Expand All @@ -175,6 +191,64 @@ - (void)setState:(PullToRefreshViewState)state_ {
[self setNeedsLayout];
}

- (BOOL)isScrolledToVisible {
if (isBottom) {
BOOL scrolledBelowContent;
if (scrollView.contentSize.height < scrollView.frame.size.height) {
scrolledBelowContent = scrollView.contentOffset.y > 0.0f;
} else {
scrolledBelowContent = scrollView.contentOffset.y > (scrollView.contentSize.height - scrollView.frame.size.height);
}
return scrolledBelowContent && ![self isScrolledToLimit];
} else {
BOOL scrolledAboveContent = scrollView.contentOffset.y < 0.0f;
return scrolledAboveContent && ![self isScrolledToLimit];
}
}

- (BOOL)isScrolledToLimit {
if (isBottom) {
if (scrollView.contentSize.height < scrollView.frame.size.height) {
return scrollView.contentOffset.y >= -kPullToRefreshViewTriggerOffset;
} else {
return scrollView.contentOffset.y >= (scrollView.contentSize.height - scrollView.frame.size.height) - kPullToRefreshViewTriggerOffset;
}
} else {
return scrollView.contentOffset.y <= kPullToRefreshViewTriggerOffset;
}
}

- (void)parkVisible {
if (isBottom) {
CGFloat extra = (scrollView.frame.size.height - scrollView.contentSize.height);
if (extra < 0.0f) extra = 0.0f;
scrollView.contentInset = UIEdgeInsetsMake(0.0f, 0.0f, -kPullToRefreshViewTriggerOffset + extra, 0.0f);
} else {
scrollView.contentInset = UIEdgeInsetsMake(-kPullToRefreshViewTriggerOffset, 0.0f, 0.0f, 0.0f);
}
}

- (void)handleDragWhileLoading {
if ([self isScrolledToLimit] || [self isScrolledToVisible]) {
// allow scrolled portion of view to display
if (isBottom) {
CGFloat extra = (scrollView.frame.size.height - scrollView.contentSize.height);
if (extra < 0.0f) extra = 0.0f;
CGFloat visiblePortion = scrollView.contentOffset.y - (scrollView.contentSize.height - scrollView.frame.size.height);
scrollView.contentInset = UIEdgeInsetsMake(0.0f, 0.0f, fminf(visiblePortion, -kPullToRefreshViewTriggerOffset + extra), 0.0f);
} else {
scrollView.contentInset = UIEdgeInsetsMake(fminf(-scrollView.contentOffset.y, -kPullToRefreshViewTriggerOffset), 0.0f, 0.0f, 0.0f);
}
}
}

- (void)updatePosition {
if (isBottom) {
CGFloat bottomOffset = (scrollView.contentSize.height < scrollView.bounds.size.height) ? scrollView.bounds.size.height : scrollView.contentSize.height;
self.frame = CGRectMake(0.0f, bottomOffset, scrollView.bounds.size.width, scrollView.bounds.size.height);
}
}

#pragma mark -
#pragma mark UIScrollView

Expand All @@ -184,26 +258,19 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N
// if we were in a refresh state
if (state == kPullToRefreshViewStateReady) {
// but now we're in between the "trigger" offset and 0
if (scrollView.contentOffset.y > kPullToRefreshViewTriggerOffset && scrollView.contentOffset.y < 0.0f) {
if ([self isScrolledToVisible]) {
// reset to "pull me to refresh!"
[self setState:kPullToRefreshViewStateNormal];
}
} else if (state == kPullToRefreshViewStateNormal) {
// if we're in a normal state and we're above the top of the scrollView and we pass the max
if (scrollView.contentOffset.y < kPullToRefreshViewTriggerOffset) {
if ([self isScrolledToLimit]) {
// go to the ready state.
[self setState:kPullToRefreshViewStateReady];
}
} else if (state == kPullToRefreshViewStateLoading || state == kPullToRefreshViewStateProgrammaticRefresh) {
// if the user scrolls the view down while we're loading, make sure the loading screen is visible if they scroll to the top:

if (scrollView.contentOffset.y >= 0) {
// this lets the table headers float to the top
scrollView.contentInset = UIEdgeInsetsZero;
} else {
// but show loading if they go past the top of the tableview
scrollView.contentInset = UIEdgeInsetsMake(fminf(-scrollView.contentOffset.y, -kPullToRefreshViewTriggerOffset), 0, 0, 0);
}
// if the user scrolls the view down while we're loading, make sure the loading screen is visible if they scroll to the top or bottom:
[self handleDragWhileLoading];
}
} else {
if (state == kPullToRefreshViewStateReady) {
Expand All @@ -221,15 +288,17 @@ - (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(N

// Fix for view moving laterally with webView
self.frame = CGRectMake(scrollView.contentOffset.x, self.frame.origin.y, self.frame.size.width, self.frame.size.height);
}
} else if ([keyPath isEqualToString:@"contentSize"]) {
[self updatePosition];
}
}

#pragma mark -
#pragma mark Memory management

- (void)containingViewDidUnload {
[scrollView removeObserver:self forKeyPath:@"contentOffset"];
[scrollView release];
[scrollView removeObserver:self forKeyPath:@"contentSize"];
scrollView = nil;
}

Expand Down
3 changes: 2 additions & 1 deletion README
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Original file line number Diff line number Diff line change
Expand Up @@ -4,6 +4,7 @@ It is:
- a pull-to-refresh implementation
- very easy to implement
- doesn't suck
- works from the top or bottom of the screen

To implement it:
- add the four files (PullToRefreshView.{h,m}, arrow.png and arrow@2x.png) to your project
Expand All @@ -12,7 +13,7 @@ To implement it:
- add QuartzCore to your project
- add an ivar: PullToRefreshView *pull; // or whatever you want to name it
- in loadView or viewDidLoad, add this (and be sure to release in dealloc/viewDidUnload, etc):
pull = [[PullToRefreshView alloc] initWithScrollView:<your scroll view here>];
pull = [[PullToRefreshView alloc] initWithScrollView:<your scroll view here> atBottom:YES/NO];
[pull setDelegate:self];
[<your scroll view here> addSubview:pull];
- in dealloc and viewDidUnload, add calls to:
Expand Down