问题
I need to create more than one UIView with MARQUEE effect like HTML <marquee>
tag.
I first need to create UIView dynamically.
After add a MARQUEE effect for dynamically created UIView.
Any help will be appreciated.
回答1:
Do you mean a view that can display a collection of strings that are wider than the view's width which it displays by slowly scrolling them from right to left? You'd need to build it. I did once, by subclassing UIScrollView like this:
// CrawlView.h
#import <UIKit/UIKit.h>
@interface CrawlView : UIScrollView
@property (assign, nonatomic) NSTimeInterval period;
@property (strong, nonatomic) NSMutableArray *messages;
- (void)go;
@end
// CrawlView.m
#import "CrawlView.h"
// distance between neighboring strings. could make this a public property
#define kPADDING 16.0
@interface CrawlView ()
@property (assign, nonatomic) CGFloat messagesWidth;
@end
@implementation CrawlView
@synthesize period=_period;
@synthesize messages=_messages;
@synthesize messagesWidth=_messagesWidth;
- (void)buildSubviews {
for (UIView *subview in [self subviews]) {
if ([subview isKindOfClass:[UILabel self]]) {
[subview removeFromSuperview];
}
}
CGFloat xPos = kPADDING;
for (NSString *message in self.messages) {
UILabel *label = [[UILabel alloc] initWithFrame:CGRectZero];
label.text = message;
CGSize size = [message sizeWithFont:label.font];
CGFloat width = size.width + kPADDING;
label.frame = CGRectMake(xPos, 0.0, width, self.frame.size.height);
[self addSubview:label];
xPos += width;
}
self.messagesWidth = xPos;
self.contentSize = CGSizeMake(xPos, self.frame.size.height);
self.contentOffset = CGPointMake(-self.frame.size.width, 0.0);
}
- (void)setMessages:(NSMutableArray *)messages {
if (_messages != messages) {
_messages = messages;
[self buildSubviews];
}
}
- (void)go {
if (!self.period) self.period = self.messagesWidth / 100;
// so it always takes about the same (fudged, but reasonable) amount of time to scroll the whole array
[UIView animateWithDuration:self.period
delay:0.0
options:UIViewAnimationOptionCurveLinear |UIViewAnimationOptionRepeat
animations:^{
self.contentOffset = CGPointMake(self.messagesWidth, 0.0);
} completion:^(BOOL finished){}];
}
@end
来源:https://stackoverflow.com/questions/9919455/how-to-create-dynamic-more-than-one-uiview-with-marquee-effect-in-iphone