某天，偶然打开了QQ音乐，又偶然打开了它的弹幕，闲着没事就搜索了一下别人的代码，发现都不是特别还原，于是就。。。

1.先看效果

• 效果(一)

  
  
  pop (1).gif

• 效果(二)

  
  
  ttttt.gif

2.弹幕消息处理

// 收到一条弹幕消息
- (void)receivedMessage:(DHBarrageMessage *)message {
  
    NSInteger iIndex = [self iIndex];
    if (iIndex == -1) {
        /// 通道满了就移除第一条弹幕 -> 消息队列添加 -> 一条消息 -> cell缓存队列移除最后一个 -> 开启定时器检测 -> 等待通道释放 -> 更新
        [self.subviews.firstObject removeFromSuperview];
        [_barrageMessages addObject:message];
        [_barrageCells removeLastObject];
        if (!_timer) {
            _timer = [CADisplayLink displayLinkWithTarget:self selector:@selector(update)];
            [_timer addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
        }
    } else {
        /// 有空余通道直接显示
        [self showBarrageCellWithBarrageMessage:message idleIndex:iIndex];
    }
}

3.弹幕显示

// 显示弹幕消息
- (void)showBarrageCellWithBarrageMessage:(DHBarrageMessage *)message iIndex:(NSInteger)iIndex {
    if (!_cellClass) {
        _cellClass = [DHBarrageViewCell class];
    }
    DHBarrageChannel *channel = _channels[iIndex]; // 获取通道
    DHBarrageViewCell *cell = [[_cellClass alloc] initWithFrame:CGRectMake(0, 0, 0, _channelHeight)];
    [cell setValue:message forKey:@"message"];
    cell.frame = ({
        CGRect frame = cell.frame;
        frame.size.width = [cell setupSubviews:iIndex];
        frame.origin.x = 0;
        frame.origin.y = self.frame.size.height-(_channelHeight+_lineSpacing);
        frame.size.height = _channelHeight;
        frame;
    });
    [self addSubview:cell];
    [channel.cells addObject:cell];
    channel.lastCell = cell;
    [_barrageCells insertObject:cell atIndex:0];
    cell.layer.anchorPoint = CGPointMake(0, 1);
    [self.layer addSublayer:cell.layer];
    // 创建组动画
    CAAnimation *animScale = [CAAnimationTool scaleAnimationFromValue:0 toValue:1.f duration:0.3];
    CAAnimation *opacity = [CAAnimationTool opacityAnimationFromValue:0 toValue:1.f duration:0.3];
    CAAnimation *animx = [CAAnimationTool positionXAnimationFromValue:0 toValue:10 duration:0.3];
    CAAnimation *animy = [CAAnimationTool positionYAnimationFromValue:self.frame.size.height toValue:self.frame.size.height-_channelHeight-_lineSpacing - _channelHeight/2 duration:0.3];
    CAAnimationGroup *group = [[CAAnimationGroup alloc] init];
    group.animations = @[animScale,opacity,animx,animy];
    group.duration = 1.0;
    group.removedOnCompletion = NO;
    group.fillMode = kCAFillModeForwards;
    group.delegate = self;
    [cell.layer addAnimation:group forKey:nil];
}

随便贴了点核心代码 源码DEMO地址