Flutter PIP 插件 ---- iOS Video Call

以下是一篇关于在 iOS 中实现画中画(PiP)功能的技术博客:

iOS 画中画(PiP)功能实现指南

简介

画中画(Picture in Picture, PiP)是一项允许用户在使用其他应用时继续观看视频内容的功能。本文将详细介绍如何在 iOS 应用中实现 PiP 功能。

系统要求

iOS 15.0 及以上版本
AVKit 框架

核心组件

实现 PiP 功能主要涉及以下几个核心组件:

AVPictureInPictureController - 负责管理 PiP 会话
AVPictureInPictureControllerContentSource - 定义 PiP 内容源
AVPictureInPictureVideoCallViewController - 控制 PiP 窗口的视图控制器

实现步骤

1. 检查设备支持

首先需要检查设备是否支持 PiP 功能:

- (BOOL)isSupported {if (@available(iOS 15.0, *)) {return [AVPictureInPictureController isPictureInPictureSupported];}return NO;
}

2. 创建 PiP 视图

需要创建一个自定义视图来显示 PiP 内容:

@interface PipView : UIView
@end@implementation PipView
+ (Class)layerClass {return [AVSampleBufferDisplayLayer class];
}
@end

3. 配置 PiP 控制器

设置 PiP 控制器需要以下步骤:

- (BOOL)setup:(PipOptions *)options {if (!self.isSupported) {return NO;}if (@available(iOS 15.0, *)) {// 创建 PiP 视图_pipView = [[PipView alloc] init];// 创建视图控制器AVPictureInPictureVideoCallViewController *pipViewController = [[AVPictureInPictureVideoCallViewController alloc] init];pipViewController.preferredContentSize = options.preferredContentSize;[pipViewController.view addSubview:_pipView];// 创建内容源AVPictureInPictureControllerContentSource *contentSource =[[AVPictureInPictureControllerContentSource alloc]initWithActiveVideoCallSourceView:options.sourceContentViewcontentViewController:pipViewController];// 初始化 PiP 控制器_pipController = [[AVPictureInPictureController alloc]initWithContentSource:contentSource];_pipController.delegate = self;_pipController.canStartPictureInPictureAutomaticallyFromInline = options.autoEnterEnabled;return YES;}return NO;
}

4. 控制 PiP 会话

启动 PiP:

- (BOOL)start {if (!self.isSupported) {return NO;}dispatch_after(dispatch_time(DISPATCH_TIME_NOW, NSEC_PER_SEC * 0.1),dispatch_get_main_queue(), ^{if (self->_pipController.isPictureInPicturePossible) {[self->_pipController startPictureInPicture];}});return YES;
}

停止 PiP:

- (void)stop {if (self->_pipController.isPictureInPictureActive) {[self->_pipController stopPictureInPicture];}
}

释放资源:

- (void)dispose {if (@available(iOS 15.0, *)) {self->_pipController.contentSource = nil;}if (self->_isPipActived) {self->_isPipActived = NO;[self->_pipStateDelegate pipStateChanged:PipStateStopped error:nil];}
}

5. 实现状态回调

通过实现 AVPictureInPictureControllerDelegate 协议来处理 PiP 状态变化:

- (void)pictureInPictureControllerDidStartPictureInPicture:(AVPictureInPictureController *)pictureInPictureController {_isPipActived = YES;[_pipStateDelegate pipStateChanged:PipStateStarted error:nil];
}- (void)pictureInPictureControllerDidStopPictureInPicture:(AVPictureInPictureController *)pictureInPictureController {_isPipActived = NO;[_pipStateDelegate pipStateChanged:PipStateStopped error:nil];
}- (void)pictureInPictureController:(AVPictureInPictureController *)pictureInPictureControllerfailedToStartPictureInPictureWithError:(NSError *)error {[_pipStateDelegate pipStateChanged:PipStateFailed error:error.description];
}