代码详解iOS视频直播弹幕功能

@interface BarrageModel : NSObject/** 用户昵称 */@property(nonatomic,copy)NSString *userName;/** 消息内容 */@property(nonatomic,copy)NSString *userMsg;/** 用户头像 */@property(nonatomic,copy)NSString *userHeadImageUrl;@end

#import <UIKit/UIKit.h>@class BarrageModel;@interface BarrageView : UIView/** * 记录当前最后一个弹幕View，通过这个View来计算是显示在哪个弹幕轨道上 */@property(nonatomic,retain) UIView *lastAnimateView;/** * 发送弹幕 * * @param msgModel 弹幕数据Model */-(void)barrageSendMsg:(BarrageModel *)msgModel;@end

#import <UIKit/UIKit.h>@class BarrageModel;@interface BarrageView : UIView

/** * 记录当前最后一个弹幕View，通过这个View来计算是显示在哪个弹幕轨道上 */@property(nonatomic,retain) UIView *lastAnimateView;/** * 发送弹幕 * * @param msgModel 弹幕数据Model */-(void)barrageSendMsg:(BarrageModel *)msgModel;@end在.m文件中#import "BarrageView.h"#import "BarrageModel.h"//屏幕的尺寸#define SCREEN_FRAME  [[UIScreen mainScreen] bounds]//屏幕的高度#define SCREEN_HEIGHT CGRectGetHeight(SCREEN_FRAME)//屏幕的宽度#define SCREEN_WIDTH CGRectGetWidth(SCREEN_FRAME)

@interface BarrageView(){  CGFloat _minSpaceTime; /** 最小间距时间 */}/** 数据源 */@property (nonatomic,retain)NSMutableArray *dataArr;

/** 弹幕UI的重用池 */@property (nonatomic,retain)NSMutableArray *resuingArr;@end@implementation BarrageView- (instancetype)initWithFrame:(CGRect)frame{  self = [super initWithFrame:frame];  if (self) {    [self setInterface];  }  return self;}-(void)setInterface{  //初始化弹幕数据源，以及重用池  self.dataArr = [NSMutableArray array];  self.resuingArr = [NSMutableArray array];  //创建第一个弹幕加入重用池作为备用  UIView *view = [self createUI];  [self.resuingArr addObject:view];  //设置弹幕数据的初始轮询时间  _minSpaceTime = 1;  //检查是否可以取弹幕数据进行动画  [self checkStartAnimatiom];}-(void)checkStartAnimatiom{  //当有数据信息的时候  if (self.dataArr.count>0) {    if (self.resuingArr.count>0) { //当重用池里面有备用的弹幕UI时            //在重用池中，取出第一个弹幕UI      UIView *view = [self.resuingArr firstObject];      [self.resuingArr removeObject:view];      //取出的这个弹幕UI开始动画      [self startAnimationWithView:view];          }else{ //当重用池没有备用的弹幕UI时            //重新创建一个弹幕UI      UIView *view = [self createUI];      //拿着这个弹幕UI开始动画      [self startAnimationWithView:view];    }  }  //延迟执行，在主线程中不能调用sleep()进行延迟执行  //调用自身方法，构成一个无限循环，不停的轮询检查是否有弹幕数据  dispatch_after(dispatch_time(DISPATCH_TIME_NOW, (int64_t)(_minSpaceTime * NSEC_PER_SEC)), dispatch_get_main_queue(), ^{    [self checkStartAnimatiom];  });}-(void)startAnimationWithView:(UIView *)view{  //取出第一条数据  BarrageModel *barrageModel = [self.dataArr firstObject];  //计算昵称的长度  CGSize nameSize = [barrageModel.userName boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, 14) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading attributes:@{                                                                         } context:nil].size;  //计算消息的长度  CGSize msgSize = [barrageModel.userMsg boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, 14) options:NSStringDrawingUsesLineFragmentOrigin|NSStringDrawingUsesFontLeading attributes:@{                                                               NSFontAttributeName:[UIFont systemFontOfSize:14]} context:nil].size;   UIImageView *headImageView; //头像  UILabel *userNameLabel;   //昵称  UILabel *userMsgLabel;   //消息内容  //进行赋值，宽度适应  for (UIView *subView in view.subviews) {    if (subView.tag == 1000) {      headImageView = (UIImageView *)subView;      headImageView.image = [UIImage imageNamed:@""];          }else if (subView.tag == 1001){      userNameLabel = (UILabel *)subView;      userNameLabel.text = barrageModel.userName;      //重新设置名称Label宽度      CGRect nameRect = userNameLabel.frame;      nameRect.size.width = nameSize.width;      userNameLabel.frame = nameRect;    }else{      userMsgLabel = (UILabel *)subView;      userMsgLabel.text = barrageModel.userMsg;      //重新设置消息内容Label宽度      CGRect msgRect = userMsgLabel.frame;      msgRect.size.width = msgSize.width;      userMsgLabel.frame = msgRect;    }  }  //重新设置弹幕的总体宽度 = 头像宽度 + 头像左右两侧距离 + (如果名字宽度大于消息内容宽度，以名字宽度为基准，如果名字宽度小于消息内容宽度，以消息内容宽度为基准)  view.frame = CGRectMake(SCREEN_WIDTH, 0, CGRectGetWidth(headImageView.frame) + 4 + (CGRectGetWidth(userNameLabel.frame)>CGRectGetWidth(userMsgLabel.frame)?CGRectGetWidth(userNameLabel.frame):CGRectGetWidth(userMsgLabel.frame)), CGRectGetHeight(self.frame));  //不管弹幕长短，速度要求一致。 V(速度) 为固定值 = 100(可根据实际自己调整)  // S = 屏幕宽度+弹幕的宽度 V = 100(可根据实际自己调整)  // V(速度) = S(路程)/t(时间) -------> t(时间) = S(路程)/V(速度);  CGFloat duration = (view.frame.size.width+SCREEN_WIDTH)/100;  //最小间距运行时间为：弹幕从屏幕外完全移入屏幕内的时间 + 间距的时间  _minSpaceTime = (view.frame.size.width + 30)/100;  //最后做动画的view  _lastAnimateView = view;    //弹幕UI开始动画  [UIView animateWithDuration:duration delay:0 options:UIViewAnimationOptionCurveLinear animations:^{    //运行至左侧屏幕外    CGRect frame = view.frame;    view.frame = CGRectMake(-frame.size.width, 0, frame.size.width, frame.size.height);  } completion:^(BOOL finished) {    //动画结束重新回到右侧初始位置    view.frame = CGRectMake(SCREEN_WIDTH, 0, 0, CGRectGetHeight(self.frame));    //重新加入重用池    [self.resuingArr addObject:view];  }];    //将这个弹幕数据移除  [self.dataArr removeObject:barrageModel];}#pragma mark public method-(void)barrageSendMsg:(BarrageModel *)msgModel{  //添加弹幕数据  [self.dataArr addObject:msgModel];}#pragma mark 创建控件-(UIView *)createUI{  UIView *view = [[UIView alloc] initWithFrame:CGRectMake(SCREEN_WIDTH, 0, 0, CGRectGetHeight(self.frame))];  view.backgroundColor = [UIColor colorWithWhite:0 alpha:0.3];  UIImageView *headImageView = [[UIImageView alloc] initWithFrame:CGRectMake(2, 2, CGRectGetHeight(self.frame)-4, CGRectGetHeight(self.frame)-4)];  headImageView.layer.cornerRadius = headImageView.frame.size.width/2;  headImageView.layer.masksToBounds = YES;  headImageView.tag = 1000;  headImageView.backgroundColor = [UIColor redColor];  [view addSubview:headImageView];  UILabel *userNameLabel = [[UILabel alloc] initWithFrame:CGRectMake(CGRectGetMaxX(headImageView.frame) + 2, 0, 0,14)];  userNameLabel.font = [UIFont systemFontOfSize:14];  userNameLabel.tag = 1001;  [view addSubview:userNameLabel];  UILabel *userMsgLabel = [[UILabel alloc] initWithFrame:CGRectMake(CGRectGetMaxX(headImageView.frame)+2, CGRectGetMaxY(userNameLabel.frame), 0, 14)];  userMsgLabel.font = [UIFont systemFontOfSize:14];  userMsgLabel.tag = 1002;  [view addSubview:userMsgLabel];  [self addSubview:view];  return view;}

#import "ViewController.h"#import "BarrageView.h"#import "BarrageModel.h"//屏幕的尺寸#define SCREEN_FRAME [[UIScreen mainScreen] bounds]//屏幕的高度#define SCREEN_HEIGHT CGRectGetHeight(SCREEN_FRAME)//屏幕的宽度#define SCREEN_WIDTH CGRectGetWidth(SCREEN_FRAME)@interface ViewController ()/** 第一个弹幕轨道 */@property (nonatomic,retain)BarrageView *barrageViewOne;/** 第二个弹幕轨道 */@property (nonatomic,retain)BarrageView *barrageViewTwo;@end@implementation ViewController- (void)viewDidLoad { [super viewDidLoad]; //创建第一个弹幕轨道 _barrageViewOne = [[BarrageView alloc]initWithFrame:CGRectMake(0,200, SCREEN_WIDTH, 34)]; [self.view addSubview:_barrageViewOne]; //创建第二个弹幕轨道 _barrageViewTwo = [[BarrageView alloc]initWithFrame:CGRectMake(0,300, SCREEN_WIDTH, 34)]; [self.view addSubview:_barrageViewTwo];}-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{ NSTimer *timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(sendMessage) userInfo:nil repeats:YES]; [timer fire];}-(void)sendMessage{ BarrageModel *model = [[BarrageModel alloc]init]; model.userName = @[@"张三",@"李四",@"王五",@"赵六",@"七七",@"八八",@"九九",@"十十",@"十一",@"十二",@"十三",@"十四"][arc4random()%12]; model.userMsg = @[@"阿达个人",@"都是vsqe12qwe",@"胜多负少的凡人歌",@"委屈翁二群二",@"12312",@"热帖柔荑花",@"发彼此彼此",@"OK泼墨",@"人体有图图",@"额外热无若无",@"微软将围"][arc4random()%11]; //计算当前做动画的弹幕UI的位置 CGFloat onePositon = _barrageViewOne.lastAnimateView.layer.presentationLayer.frame.size.width + _barrageViewOne.lastAnimateView.layer.presentationLayer.frame.origin.x; //计算当前做动画的弹幕UI的位置 CGFloat twoPositon = _barrageViewTwo.lastAnimateView.layer.presentationLayer.frame.size.width + _barrageViewTwo.lastAnimateView.layer.presentationLayer.frame.origin.x; if ( onePositon < twoPositon ) { [_barrageViewOne barrageSendMsg:model]; }else{ [_barrageViewTwo barrageSendMsg:model]; }}@end