如何在airplay处于活动状态时自定义Airplay按钮

Question

一直试图解决这个问题2天,我放弃了.我试图实现一个自定义的播放按钮(我必须背景是白色,按钮必须是黑色).我在interfacebuilder中添加了一个视图,并选择了mpVolumeView.然后我建立了连接并编写了以下代码;

viewDidLoad.. {
    .....

    [_volumeView setShowsVolumeSlider:NO];
    for (UIButton *button in _volumeView.subviews) {
        if ([button isKindOfClass:[UIButton class]]) {
            [button setImage:[UIImage imageNamed:@"airplay_icon.png"] forState:UIControlStateNormal];
            [button addObserver:self forKeyPath:@"alpha" options:NSKeyValueObservingOptionNew context:nil];
            [button addTarget:self action:@selector(switchAirplayButton) forControlEvents:UIControlEventTouchUpInside];
            [button sizeToFit];
        }
    }
    [_volumeView sizeToFit];

}

-(void)switchAirplayButton {

    for (UIButton *button in _volumeView.subviews) {
        if ([button isKindOfClass:[UIButton class]]) {

            NSLog(@"%d", _controlBar.player.airPlayVideoActive);

            if(_controlBar.player.airPlayVideoActive) {
                [button setImage:[UIImage imageNamed:@"airplay_icon_pressed.png"] forState:UIControlStateNormal];
            } else  [button setImage:[UIImage imageNamed:@"airplay_icon.png"] forState:UIControlStateNormal];

            [button sizeToFit];
        }
    }


}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {
    if ([object isKindOfClass:[UIButton class]] && [[change valueForKey:NSKeyValueChangeNewKey] intValue] == 1) {
        [(UIButton *)object setImage:[UIImage imageNamed:@"airplay_icon.png"] forState:UIControlStateNormal];
        [(UIButton *)object sizeToFit];
    }
}

"玩家"是基于AVPLayer的singelton.但是,在检查airPlay是否处于活动状态时,它始终返回false.也许它只是因为使用声音,而不是视频.

所以我的问题是,我怎么能将按钮更改为...当airplay正在流式播放时(就像苹果将其变为蓝色一样),让我们说一个橙色的按钮(只是为了匹配界面的其余部分).我已经尝试过所有的东西而且根本就没有用.请帮我.

Answer 1

编辑:

虽然下面的代码适用于iOS 5和6,但从iOS 6.0开始,有一种官方的方法可以做到这一点,这要容易得多.请MPVolumeView具体看一下文档– setRouteButtonImage:forState:.

====旧答案:====

这很难实现,但我找到了iOS 5.0+的方法.首先,将以下行添加到ViewController:

#import <AudioToolbox/AudioToolbox.h>

在你的viewDidLoad中,你已经完成了大部分工作,这是我的代码:

for (id current in self.volumeView.subviews){
    if([current isKindOfClass:[UIButton class]]) {
        UIButton *airPlayButton = (UIButton*)current;
        self.airPlayButton = airPlayButton;
        [self setAirPlayButtonSelected:[self isAirPlayActive]];
        [airPlayButton addObserver:self forKeyPath:@"alpha" options:NSKeyValueObservingOptionNew context:nil];
    }
}

这是辅助setAirPlayButtonSelected方法,它只是设置图像:

- (void)setAirPlayButtonSelected:(BOOL)selected {
    UIImage* image;
    if (selected) {
        image = [UIImage imageNamed:@"button-airplay-selected"];
    }else {
        image = [UIImage imageNamed:@"button-airplay"];
    }
    [self.airPlayButton setImage:image forState:UIControlStateNormal];
    [self.airPlayButton setImage:image forState:UIControlStateHighlighted];
    [self.airPlayButton setImage:image forState:UIControlStateSelected];
}

为了完成起见,observeValueForKeyPath:

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context {

    if (object == self.airPlayButton && [[change valueForKey:NSKeyValueChangeNewKey] intValue] == 1) {
        [self setAirPlayButtonSelected:[self isAirPlayActive]];
    }
}

现在是有趣的部分.这是isAirPlayActive辅助方法.它使用AudioSession框架来确定当前正在播放的audioSource.

- (BOOL)isAirPlayActive{
    CFDictionaryRef currentRouteDescriptionDictionary = nil;
    UInt32 dataSize = sizeof(currentRouteDescriptionDictionary);
    AudioSessionGetProperty(kAudioSessionProperty_AudioRouteDescription, &dataSize, &currentRouteDescriptionDictionary);
    if (currentRouteDescriptionDictionary) {
        CFArrayRef outputs = CFDictionaryGetValue(currentRouteDescriptionDictionary, kAudioSession_AudioRouteKey_Outputs);
        if(CFArrayGetCount(outputs) > 0) {
            CFDictionaryRef currentOutput = CFArrayGetValueAtIndex(outputs, 0);
            CFStringRef outputType = CFDictionaryGetValue(currentOutput, kAudioSession_AudioRouteKey_Type);
            return (CFStringCompare(outputType, kAudioSessionOutputRoute_AirPlay, 0) == kCFCompareEqualTo);
        }
    }

    return NO;
}

因此,所有这些代码都会在应用启动时正确更改AirPlay按钮.更新怎么样？我们需要监听AudioSource的变化.将以下行添加到您的viewDidLoad:

    AudioSessionAddPropertyListener (kAudioSessionProperty_AudioRouteChange, audioRouteChangeCallback, (__bridge void*)self);

不要忘记取消注册dealloc:

- (void)dealloc {
    [self.airPlayButton removeObserver:self forKeyPath:@"alpha"];

    AudioSessionRemovePropertyListenerWithUserData(kAudioSessionProperty_AudioRouteChange, audioRouteChangeCallback, (__bridge void*)self);

}

并在ViewController的上方添加此C函数@implementation:

void audioRouteChangeCallback (void                   *inUserData,
                                       AudioSessionPropertyID inPropertyID,
                                       UInt32                 inPropertyValueSize,
                                       const void             *inPropertyValue) {

    if (inPropertyID != kAudioSessionProperty_AudioRouteChange) {
        return;
    }

    CFDictionaryRef routeChangeDictionary = inPropertyValue;

    CFDictionaryRef currentRouteDescriptionDictionary = CFDictionaryGetValue(routeChangeDictionary, kAudioSession_AudioRouteChangeKey_CurrentRouteDescription);
    CFArrayRef outputs = CFDictionaryGetValue(currentRouteDescriptionDictionary, kAudioSession_AudioRouteKey_Outputs);
    if(CFArrayGetCount(outputs) > 0) {
        CFDictionaryRef currentOutput = CFArrayGetValueAtIndex(outputs, 0);
        CFStringRef outputType = CFDictionaryGetValue(currentOutput, kAudioSession_AudioRouteKey_Type);

        [(__bridge SettingsViewController*)inUserData setAirPlayButtonSelected:CFStringCompare(outputType, kAudioSessionOutputRoute_AirPlay, 0) == kCFCompareEqualTo];
    }

}

如您所见,它所做的只是确定AirPlay输出源是否处于活动状态并相应地调用该setAirPlayButtonSelected方法.

请参阅Apple的音频会话编程指南,特别是本节,了解有关回调如何正常工作的详细信息等.