一个简单的弹幕效果

说到斗鱼，很多盆友肯定都知道，作为一名斗鱼的忠实用户。对斗鱼的弹幕效果是再熟悉不过了，最近自己动手写了一个demo，效果一般，大家就看看吧。

好了，废话不多说，直接上代码。

#import "ViewController.h"

#define screenW [UIScreen mainScreen].bounds.size.width

#define textHeight 40

#define textFont 14.f

@interface ViewController (){

NSInteger _index;

CGFloat _font;

}

@property (nonatomic,strong) NSArray *titleArray;

@end

@implementation ViewController

- (NSArray *)titleArray

{

if (_titleArray == nil) {

NSString *path = [[NSBundle mainBundle] pathForResource:@"danmu.plist" ofType:nil];

_titleArray = [NSArray arrayWithContentsOfFile:path];

}

return _titleArray;

}

/**

随机颜色

随机高度

运行循环

创建label方法

动态计算label的宽高

*/

- (void)viewDidLoad {

[super viewDidLoad];

self.view.backgroundColor = [UIColor lightGrayColor];

_index = 0;

// 时间直接加入到运行循环

[NSTimer scheduledTimerWithTimeInterval:0.1 target:self selector:@selector(setUpTitleLabel) userInfo:nil repeats:YES];

}

-(void)setUpTitleLabel

{

_index ++;

if (_index == self.titleArray.count) {

_index = 0;

}

NSString *title = self.titleArray[_index];

UILabel *textLabel = [[UILabel alloc] init];

textLabel.text = title;

// textLabel.frame = [self textLabelWithString:title];

接上面

// 全局记录当前文字大小

_font = [self arc4randomFont];

textLabel.font = [UIFont systemFontOfSize:_font];

[self.view addSubview:textLabel];

textLabel.textColor = [self arc4randomColor];

// label高度

CGFloat labelY = [self arc4randomY];

textLabel.frame = CGRectMake(screenW, labelY, [self textLabelWithString:title].width, textFont);

// 从右到左

[UIView animateWithDuration:3 animations:^{

textLabel.frame = CGRectMake(-[self textLabelWithString:title].width, labelY, [self textLabelWithString:title].width, textFont);

}completion:^(BOOL finished) {

[textLabel removeFromSuperview];

}];

}

#pragma mark - 计算文本宽高方法

-(CGSize)textLabelWithString:(NSString *)string

{

return [string boundingRectWithSize:CGSizeMake(MAXFLOAT, textHeight) options:NSStringDrawingUsesLineFragmentOrigin attributes:@{NSFontAttributeName:[UIFont systemFontOfSize:_font]} context:nil].size;

}

#pragma mark - 随机颜色

-(UIColor *)arc4randomColor

{

return [UIColor colorWithRed:arc4random_uniform(256)/255.0 green:arc4random_uniform(256)/255.0 blue:arc4random_uniform(256)/255.0 alpha:1];

}