一个简单的跑马灯效果,话不多说,直接看代码
建一个UIView类
.h文件中声明三个类方法
@property (nonatomic, strong) NSString * title;
+ (instancetype)marqueeBarWithFrame:(CGRect)frame title:(NSString *)title;
- (void)updateTitle:(NSString *)title;
- (void)resume;
.m文件中
@interface MarqueeBar ()
{
NSTimer *_timer;
}
/*我这里label由俩部分构成,因而直接建俩label*/
@property (nonatomic, strong) UILabel *firstLabel;
@property (nonatomic, strong) UILabel *secondLabel;
@property (nonatomic, strong) NSMutableArray *labelArray;
@end
+ (instancetype)marqueeBarWithFrame:(CGRect)frame title:(NSString*)title
{
JCmarqueBar * marqueBar = [[JCmarqueBar alloc] initWithFrame:frame];
marqueBar.title = title;
return marqueBar;
}
- (instancetype)initWithFrame:(CGRect)frame {
self = [super initWithFrame:frame];
if (self) {
[self addSubview:self.firstLabel];
[self addSubview:self.secondLabel];
[self.labelArray addObject:_firstLabel];
[self.labelArray addObject:_secondLabel];
}
return self;
}
- (void)setTitle:(NSString *)title {
_title = title;
if (_timer) {
[_timer invalidate];
_timer = nil;
}
NSString *raceStr = [NSString stringWithFormat:@"%@ ",title];
_firstLabel.text = raceStr;
_secondLabel.text = raceStr;
self.firstLabel.frame = CGRectMake(0, 0, [self getStringWidth:raceStr], self.frame.size.height);
self.secondLabel.frame = CGRectMake(_firstLabel.frame.origin.x + _firstLabel.bounds.size.width, _firstLabel.frame.origin.y, _firstLabel.bounds.size.width, _firstLabel.bounds.size.height);
_secondLabel.hidden = ![self isNeedRaceAnimate];
if ([self isNeedRaceAnimate]) {
[self startAnimation];
}
}
- (void)updateTitle:(NSString *)title {
self.title = title;
}
- (BOOL)isNeedRaceAnimate{
return !(_firstLabel.bounds.size.width <= self.bounds.size.width);
}
- (void)layoutSubviews{
[super layoutSubviews];
if (_firstLabel && _secondLabel) {
_firstLabel.frame = CGRectMake(50, 0, _firstLabel.bounds.size.width, self.bounds.size.height);
_secondLabel.frame = CGRectMake(_firstLabel.frame.origin.x + _firstLabel.bounds.size.width, _firstLabel.frame.origin.y, _firstLabel.bounds.size.width, _firstLabel.bounds.size.height);
}
_secondLabel.hidden = ![self isNeedRaceAnimate];
}
- (void)startAnimation{
_timer = [NSTimer scheduledTimerWithTimeInterval:1.0 / 120 target:self selector:@selector(raceLabelFrameChanged:) userInfo:nil repeats:YES];
[_timer fire];
[[NSRunLoop mainRunLoop] addTimer:_timer forMode:NSRunLoopCommonModes];
}
- (void)raceLabelFrameChanged:(NSTimer *)timer
{
UILabel *firstLabel = [self.labelArray firstObject];
UILabel *secondLabel = [self.labelArray lastObject];
CGRect frameOne = firstLabel.frame;
CGRect frameTwo = secondLabel.frame;
CGFloat firstX = firstLabel.frame.origin.x;
CGFloat secondX = secondLabel.frame.origin.x;
firstX -= 0.5;
secondX -= 0.5;
if (ABS(firstX) >= firstLabel.bounds.size.width) {
firstX = secondX + firstLabel.bounds.size.width;
[self.labelArray exchangeObjectAtIndex:0 withObjectAtIndex:1];
}
frameOne.origin.x = firstX;
frameTwo.origin.x = secondX;
firstLabel.frame = frameOne;
secondLabel.frame = frameTwo;
}
- (void)resume
{
[self resumeAndStart:NO];
}
- (void)resumeAndStart
{
[self resumeAndStart:YES];
}
- (void)resumeAndStart:(BOOL)start
{
if (_timer) {
[_timer invalidate];
_timer = nil;
}
_firstLabel.frame = CGRectMake(50, 0, _firstLabel.bounds.size.width, self.bounds.size.height);
_secondLabel.frame = CGRectMake(_firstLabel.frame.origin.x + _firstLabel.bounds.size.width, _firstLabel.frame.origin.y, _firstLabel.bounds.size.width, _firstLabel.bounds.size.height);
if (start) {
[self startAnimation];
}
}
#pragma mark - Properties
- (UILabel *)firstLabel
{
if (_firstLabel == nil) {
_firstLabel = [[UILabel alloc] init];
_firstLabel.font = [UIFont systemFontOfSize:14.0];
_firstLabel.textColor = RGB(102, 102, 102, 1);
_firstLabel.textAlignment = NSTextAlignmentCenter;
}
return _firstLabel;
}
- (UILabel *)secondLabel {
if (_secondLabel == nil) {
_secondLabel = [[UILabel alloc] init];
_secondLabel.font = [UIFont systemFontOfSize:14.0];
_secondLabel.textColor = RGB(102, 102, 102, 1);
_secondLabel.textAlignment = NSTextAlignmentCenter;
}
return _secondLabel;
}
- (NSMutableArray *)labelArray{
if (!_labelArray) {
self.labelArray = [NSMutableArray arrayWithCapacity:0];
}
return _labelArray;
}
- (CGFloat)getStringWidth:(NSString *)string{
if (string) {
CGRect rect = [string boundingRectWithSize:CGSizeMake(MAXFLOAT, 0)
options:NSStringDrawingTruncatesLastVisibleLine |NSStringDrawingUsesLineFragmentOrigin |
NSStringDrawingUsesFontLeading
attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:14.0]}
context:nil];
return rect.size.width;
}
return 0.f;
}
到此,一个跑马灯的效果完成,demo地址