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];
}
#pragma mark - 随机高度
-(CGFloat)arc4randomY
{
CGFloat textY = [UIScreen mainScreen].bounds.size.height * 0.5;
return arc4random_uniform(textY);
}
#pragma mark - 随机文字大小
-(CGFloat)arc4randomFont
{
return arc4random_uniform(8) + 13;
}
@end
基本弹幕效果实现了，但是应该还有更简单的方法，欢迎大家批评指证。
