iOS視頻彈幕

前言

項目中要在原有的視頻基礎上添加彈幕功能，主要包含開始、停止、暫停、恢復、發送彈幕、彈幕點擊等小功能。找到之前一個封裝的彈幕庫，在原有的基礎上做了些功能改動和添加，寫在這裏記錄一下。

項目層級關係

DanmuSend

這塊兒主要是負責發送彈幕功能
包含DanmuSendView和DanmuOperateView，LGJDanmuOperateView主要承載彈出輸入框功能，DanmuSendView主要是監聽鍵盤及輸入內容。

Danmu

這塊兒是主要的彈幕邏輯區域
LGJDanmuUtil 配置彈幕字體大小、顏色等個性化定製
LGJDanmuLabel 彈幕顯示label
LGJDanmuView 彈幕顯示view，主要承載彈幕的label和頭像img
LGJDanmuBgView 彈幕顯示的背景view
LGJDanmuManager 彈幕功能的管理類

使用

在需要用到彈幕的vc中引入頭文件：
#import "LGJDanmuManager.h"
#import "LGJDanmuSendView.h"

這裏呢，使用了本地文件臨時充當服務器返回的對應時間點的彈幕文字。

NSString *path = [[NSBundle mainBundle] bundlePath];
    path = [[path stringByAppendingPathComponent:@"LGJDanmuSource"] stringByAppendingPathExtension:@"plist"];
    NSArray *tempInfos = [NSArray arrayWithContentsOfFile:path];
    
    NSArray *infos = [tempInfos sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {
        CGFloat v1 = [[obj1 objectForKey:kDanmuTimeKey] floatValue];
        CGFloat v2 = [[obj2 objectForKey:kDanmuTimeKey] floatValue];
        
        NSComparisonResult result = v1 <= v2 ? NSOrderedAscending : NSOrderedDescending;
        
        return result;
    }];

初始化彈幕管理類：

self.danmuManager = [[LGJDanmuManager alloc] initWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, _screenV.bounds.size.height) data:infos inView:_screenV durationTime:1];
    
    self.countTime = -1;
    [self.danmuManager initStart];

_screenV模擬的視頻播放view。

彈幕點擊事件方法：

- (void)addTapGesture {
    UITapGestureRecognizer *tap = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapHandler:)];
    tap.cancelsTouchesInView = NO;
    [self.screenV addGestureRecognizer:tap];
}

- (void)tapHandler:(UITapGestureRecognizer *)gesture {
    [self.danmuManager.danmuBgView dealTapGesture:gesture block:^(LGJDanmuView *danmuView){
        NSLog(@"點擊了：-- %@", danmuView.danmuLabel.text);
    }];
}

在這個vc中還需要有橫豎屏切換的監聽方法以及對應的處理方法:

- (void)p_prepare {
    [self.danmuSendV backAction];
    [self p_destoryTimer];
    BOOL bPlaying = self.bPlaying;
    [self stop:nil];
    self.bPlaying = bPlaying;
    [self.danmuManager resetDanmuWithFrame:CGRectMake(0, 0, [UIScreen mainScreen].bounds.size.width, _screenV.bounds.size.height)];
}

發送彈幕的代理方法：

#pragma mark - LGJDanmuSendViewDelegate

- (void)sendDanmu:(LGJDanmuSendView *)danmuSendV info:(NSString *)info {
    NSDate *now = [NSDate new];
    double t = ((double)now.timeIntervalSince1970);
    t = ((int)t)%1000;
    CGFloat nowTime = self.countTime + t*0.0001;
    [self.danmuManager insertDanmu:@{kDanmuContentKey:info, kDanmuTimeKey:@(nowTime), kDanmuOptionalKey:@"df"}];
    
    if (self.bPlaying)
        [self resume:nil];
}

- (void)closeSendDanmu:(LGJDanmuSendView *)danmuSendV {
    if (self.bPlaying)
        [self resume:nil];
}

點擊開始按鈕，開始滾動彈幕

- (IBAction)start:(id)sender {
    [self.danmuManager initStart];
    self.bPlaying = YES;
    
    if ([_timer isValid]) {
        return;
    }
    if (_timer == nil) {
        __weak typeof(self) weakSelf = self;
        self.timer = [NSTimer eoc_scheduledTimerWithTimeInterval:1 block:^{
            ViewController *strogSelf = weakSelf;
            [strogSelf progressVideo];
        } repeats:YES];
    }
}

- (void)progressVideo {
    self.countTime++;
    [_danmuManager rollDanmu:_countTime];
}

LGJDanmuManager

這個類是彈幕的管理類，主要的方法及實現方法都在這裏

首先初始化數據

- (instancetype)initWithFrame:(CGRect)frame data:(NSArray *)infos inView:(UIView *)view durationTime:(NSUInteger)time {
    self = [super init];
    if (self) {
//        self.frame = frame;
        CGRect tempFrame = CGRectMake(frame.origin.x, frame.origin.y, frame.size.width, 100);
        self.frame = tempFrame;
        self.infos = [infos mutableCopy];
        self.superView = view;
        self.durationTime = time;
        
        self.danmuQueue = dispatch_queue_create("com.danmu.queue", NULL);
        
        [self p_initInfo];
    }
    return self;
}

#pragma mark - Private

- (void)p_initInfo {
    _countChannel = self.frame.size.height/CHANNEL_HEIGHT;
    
    self.arRollChannelInfo = [NSMutableArray arrayWithCapacity:_countChannel];
    self.arFadeChannelInfo = [NSMutableArray arrayWithCapacity:2];
    
    NSUInteger sectionLines = nearbyintf((CGFloat)_countChannel / 3);
    NSUInteger firstLines = MAX(_countChannel - sectionLines*2, sectionLines);
    //滾動航道佈局
    {
        //上中下，假設10，上：0-3，中：4-6，下：7-9
        _upPosition = (DanmuPositionStruct){0, firstLines};
        _middlePosition = (DanmuPositionStruct){_upPosition.length, sectionLines};
        _downPosition = (DanmuPositionStruct){_middlePosition.start + _middlePosition.length, _countChannel - _middlePosition.start - _middlePosition.length};
        //上中下，假設10，上：0-9，中：4-9，下：7-9
        _upPosition = (DanmuPositionStruct){0, _countChannel};
        _middlePosition = (DanmuPositionStruct){firstLines, _upPosition.length - firstLines};
        _downPosition = (DanmuPositionStruct){_middlePosition.start + sectionLines, _upPosition.length - firstLines - sectionLines};
    }
    //浮現航道佈局，這裏選擇的是上面滾動航道佈局，所以不一定是現在這樣子
    {
        //第一層：上中下，假設10，上：0-9，中：4-9，下：7-9，
        _upFadeOnePosition = _upPosition;
        _middleFadeOnePosition = _middlePosition;
        _downFadeOnePosition = _downPosition;
        //由於上一層爲10，第二層爲9，上：0-8，中：4-8，下：7-8
        _upFadeTwoPosition = (DanmuPositionStruct){_upFadeOnePosition.start, _upFadeOnePosition.length - 1};
        _middleFadeTwoPosition = (DanmuPositionStruct){_middleFadeOnePosition.start, _middleFadeOnePosition.length - 1};
        _downFadeTwoPosition = (DanmuPositionStruct){_downFadeOnePosition.start, _downFadeOnePosition.length - 1};
    }
    
    _danmuManagerState = DanmuManagerStateWait;
}

- (void)p_initData {
    [self.arRollChannelInfo removeAllObjects];
    
    for (int i = 0; i < _countChannel; i++) {
        [self.arRollChannelInfo addObject:[NSNumber numberWithInt:i]];
    }
    
    [self.arFadeChannelInfo removeAllObjects];
    
    NSMutableArray *ar1 = [NSMutableArray new];
    for (int i = 0; i < _countChannel; i++) {
        [ar1 addObject:[NSNumber numberWithInt:i]];
    }
    [self.arFadeChannelInfo addObject:ar1];
    NSMutableArray *ar2 = [NSMutableArray new];
    for (int i = 0; i < _countChannel - 1; i++) {
        [ar2 addObject:[NSNumber numberWithInt:i]];
    }
    [self.arFadeChannelInfo addObject:ar2];
    
    self.currentIndex = 0;
    
    [self.danmuBgView removeFromSuperview];
    self.danmuBgView = nil;
    LGJDanmuBgView *danmuBgView = [[LGJDanmuBgView alloc] initWithFrame:_frame];
    self.danmuBgView = danmuBgView;
    self.danmuBgView.backgroundColor = [UIColor lightGrayColor];
    [self.superView addSubview:self.danmuBgView];
    
    _danmuManagerState = DanmuManagerStateWait;
}

開始滾動彈幕

- (void)p_danmu:(NSTimeInterval)startTime
遍歷danmuInfos從danmuInfos（彈幕信息）中獲取彈幕文字內容、創建danmuView，對新創建的danmuView選擇出合適的航道，獲取到合適的航道後開始動畫。主要原理是這樣，至於合適的航道怎麼選擇，可以參考代碼。

//選擇在不超出緩衝區的且緩衝區最長的航道
- (NSUInteger)p_allChannelWithPosition:(DanmuPositionStruct)danmuPosition new:(LGJDanmuView *)newDanmuL {
    CGFloat width = CHANNEL_WIDTH_MAX;
    NSUInteger index = NSNotFound;
    for (int i = (int)danmuPosition.start; i < danmuPosition.start + danmuPosition.length; i++) {id obj = [self.arRollChannelInfo objectAtIndex:i];
        if ([obj isKindOfClass:[LGJDanmuView class]]) {
            CGFloat rightX = ((LGJDanmuView *)obj).currentRightX;
            if (rightX <= CHANNEL_WIDTH_MAX) {
                CGFloat xx = rightX;
                if (xx < width) {
                    width = xx;
                    index = i;
                }
            }
        }
    }
    
    return index;
}

//選擇不會碰撞的航道
- (BOOL)p_last:(LGJDanmuView *)lastDanmuL new:(LGJDanmuView *)newDanmuL {
    CGFloat durationTime = newDanmuL.startTime - lastDanmuL.startTime;
    if (durationTime > newDanmuL.animationDuartion) {
        return YES;
    }
    CGFloat timeS = lastDanmuL.frame.size.width/lastDanmuL.speed;
    if (timeS >= durationTime) {
        return NO;
    }
    CGFloat timeE = newDanmuL.currentRightX/newDanmuL.speed;
    if (timeE <= durationTime) {
        return NO;
    }
    
    return YES;
}

#獲取合適的航道、danmuView、offsetXY
- (void)p_getRollBestChannel:(LGJDanmuView *)newDanmuL completion:(void(^)(NSUInteger idx, CGFloat offsetX))completion {
    DanmuPositionStruct danmuPosition;
    if (newDanmuL.isPositionMiddle) {
        danmuPosition = _middlePosition;
    }
    else if (newDanmuL.isPositionBottom) {
        danmuPosition = _downPosition;
    }
    else {
        danmuPosition = _upPosition;
    }
    
    NSUInteger index = danmuPosition.start;
    BOOL bFind = NO;
    for (int i = (int)danmuPosition.start; i < danmuPosition.start + danmuPosition.length; i++) {
        id obj = [self.arRollChannelInfo objectAtIndex:i];
        index = i;
        if ([obj isKindOfClass:[LGJDanmuView class]]) {
            bFind = [self p_last:obj new:newDanmuL];
        }else {
            bFind = YES;
        }
        
        if (bFind)
            break;
    }
    
    if (bFind) {
        id obj = [self.arRollChannelInfo objectAtIndex:index];
        [self.arRollChannelInfo replaceObjectAtIndex:index withObject:newDanmuL];
        if ([obj isKindOfClass:[LGJDanmuView class]]) {
            CGFloat x = ((LGJDanmuView *)obj).currentRightX;
            completion(index, x < 0 ? 0 : x);
        }else
            completion(index, 0);
    }else {
        if (index < danmuPosition.start + danmuPosition.length - 1) {
            index += 1;
            [self.arRollChannelInfo replaceObjectAtIndex:index withObject:newDanmuL];
            completion(index, 0);
        }
        else {
            NSUInteger index = NSNotFound;
            index = [self p_allChannelWithPosition:danmuPosition new:newDanmuL];
            if (index != NSNotFound) {
                LGJDanmuView *obj = [self.arRollChannelInfo objectAtIndex:index];
                [self.arRollChannelInfo replaceObjectAtIndex:index withObject:newDanmuL];
                CGFloat x = obj.currentRightX;
                completion(index, x < CHANNEL_SPACE ? CHANNEL_SPACE : x);
            }else
                completion(NSNotFound, 0);
        }
    }
}

停止

- (void)stop {
    dispatch_sync(self.danmuQueue, ^{
        _danmuManagerState = DanmuManagerStateStop;
        [self.arRollChannelInfo removeAllObjects];
        [self.arFadeChannelInfo removeAllObjects];
        dispatch_async(dispatch_get_main_queue(), ^{
            [self.danmuBgView.subviews makeObjectsPerformSelector:@selector(removeDanmu)];
            [self.danmuBgView removeFromSuperview];
        });
    });
}

暫停

- (void)pause {
    if (_danmuManagerState != DanmuManagerStateAnimationing)
        return;
    dispatch_sync(self.danmuQueue, ^{
        _danmuManagerState = DanmuManagerStatePause;
        [self.danmuBgView.subviews makeObjectsPerformSelector:@selector(pause)];
    });
}

恢復

- (void)resume:(NSTimeInterval)nowTime {
    if (_danmuManagerState != DanmuManagerStatePause)
        return;
    dispatch_sync(self.danmuQueue, ^{
        _danmuManagerState = DanmuManagerStateAnimationing;
        for (id subview in self.danmuBgView.subviews) {
            if ([subview isKindOfClass:[LGJDanmuView class]]) {
                [(LGJDanmuView *)subview resume:nowTime];
            }
        }
    });
}

插入新彈幕

- (void)insertDanmu:(NSDictionary *)info {
    dispatch_sync(self.danmuQueue, ^{
        id optional = [LGJDanmuUtil defaultOptions];
        __block LGJDanmuView *danmuView = [LGJDanmuView createWithInfo:info optional:optional inView:self.danmuBgView hasHeaderIcon:YES];
        if ([danmuView isMoveModeFadeOut]) {
            [self p_getFadeBestChannel:danmuView completion:^(NSUInteger idx, CGFloat offsetY) {
                if (idx != NSNotFound) {
                    [danmuView setDanmuChannel:idx offset:offsetY];
                }
            }];
        }
        else {
            [self p_getRollBestChannel:danmuView completion:^(NSUInteger idx, CGFloat offsetX) {
                if (idx != NSNotFound) {
                    [danmuView setDanmuChannel:idx offset:offsetX];
                }
            }];
        }
    });
}

主要的功能點就是這些，但是具體的細節還是在代碼裏面，但是實現方式也不侷限與代碼中的這一種，每個人有每個人的思路，要是覺得有些地方比較晦澀也可以使用別的方式代替。這個基本上可以滿足平常視頻彈幕的基本功能需求了。

代碼鏈接：