前言
開發(fā)時有一個需求是實現(xiàn)跑馬燈效果，其實跑馬燈還是比較容易實現(xiàn)的侣诺，但是這個是一個局部范圍的跑馬燈殖演，平時使用的都是全屏幕長度的跑馬燈，經(jīng)過一番折騰年鸳，找的了重點(diǎn),下面這句代碼就是我們實現(xiàn)局部的關(guān)鍵趴久。
@property(nonatomic) BOOL clipsToBounds; // When YES, content and subviews are clipped to the bounds of the view. Default is NO.
效果圖
未命名.gif
代碼
//.h
#import <UIKit/UIKit.h>
@interface HHRunLabelView : UIView
//字體顏色
@property (nonatomic, strong) UIColor *textColor;
//字體大小
@property (nonatomic, strong) UIFont *font;
//要顯示的內(nèi)容
@property (nonatomic, strong) NSString *text;
/**
移動的速度[0~1],默認(rèn)是0.2
*/
@property (nonatomic, assign) CGFloat speed;
@end
//.m
#import "HHRunLabelView.h"
@interface HHRunLabelView()
@property (nonatomic, assign) CGFloat offsetX; //x偏移量
@property (nonatomic, strong) UILabel *moveLabel;
@property (nonatomic, assign) CGFloat labelWidth; //label的寬度
@end
@implementation HHRunLabelView
- (instancetype)initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]){
_speed = 0.2;//默認(rèn)值
[self initView];
[self initTimer];
}
return self;
}
- (void)initView{
_moveLabel = [[UILabel alloc] initWithFrame:CGRectMake(0, 0, self.frame.size.width, self.frame.size.height)];
[self addSubview:_moveLabel];
}
//初始化timer
- (void)initTimer{
CADisplayLink *timer = [CADisplayLink displayLinkWithTarget:self selector:@selector(displayLabelAction)];
timer.frameInterval = 2.0;
[timer addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSRunLoopCommonModes];
}
- (void)setTextColor:(UIColor *)textColor{
_moveLabel.textColor = textColor;
}
- (void)setFont:(UIFont *)font{
_moveLabel.font = font;
}
//設(shè)置速度
- (void)setSpeed:(CGFloat)speed{
if (speed < 0) {
speed = 0;
}else if (speed > 1){
speed = 1;
}
_speed = speed*5;
}
//賦值text
- (void)setText:(NSString *)text{
_moveLabel.text = text;
[_moveLabel sizeToFit];
CGRect rect = _moveLabel.frame;
rect.size.height = self.frame.size.height;
_moveLabel.frame = rect;
_offsetX = _moveLabel.frame.origin.x;
self.clipsToBounds = YES;//設(shè)置了這個屬性后才能局部顯示
}
- (void)displayLabelAction{
_labelWidth = self.moveLabel.frame.size.width;
if (_labelWidth < self.frame.size.width) return;//如果字能顯示全則不移動
CGRect rect = self.moveLabel.frame;
_offsetX -= self.speed;
rect.origin.x = _offsetX;
self.moveLabel.frame = rect;
if (_offsetX < -_labelWidth){
_offsetX = self.frame.size.width; //重置起點(diǎn)
}
}
用法
//導(dǎo)入頭文件后加載
HHRunLabelView *runLabel = [[HHRunLabelView alloc] initWithFrame:CGRectMake(10, 100, 100, 50)];
runLabel.backgroundColor = [UIColor grayColor];
runLabel.textColor = [UIColor redColor];
runLabel.speed = 0.5;
runLabel.text = @"我是一個局部的小跑馬燈啊";
[self.view addSubview:runLabel];
Demo地址github
