iOS开发——获取UIWebView中视频的长度与播放进度等信息

在做一个upnp项目时，有在线播放视频的模块。使用的是在UIWebView中打开url链接的方式。碰到一个需求，需要获取web页面中视频的长度与及时播放进度。参考微软提供的html5视频控制相关文章后，自己写了一个UIWebView的扩展。经真机测试可用。现提供方法供广大同志们使用（敬请保留版权信息）。
.h文件

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//
// UIWebView+VideoControl.h
// Enjoy
//
// Created by zeng songgen on 12-10-15.
// Copyright (c) 2012年 zeng songgen. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UIWebView (VideoControl)

- (BOOL)hasVideo;
- (NSString *)getVideoTitle;
- (double)getVideoDuration;
- (double)getVideoCurrentTime;

- (int)play;
- (int)pause;
- (int)resume;
- (int)stop;

@end

.m文件

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<pre name="code" class="plain">//
// UIWebView+VideoControl.m
// Enjoy
//
// Created by zeng songgen on 12-10-15.
// Copyright (c) 2012年 zeng songgen. All rights reserved.
//

#import "UIWebView+VideoControl.h"

@implementation UIWebView (VideoControl)

- (BOOL)hasVideo
{
__block BOOL hasVideoTag = NO;

if (![[NSThread currentThread] isMainThread])
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);

dispatch_async(dispatch_get_main_queue(), ^{
NSString * hasVideoTestString = @"document.documentElement.getElementsByTagName(\"video\").length";
NSString * result = [self stringByEvaluatingJavaScriptFromString:hasVideoTestString];
hasVideoTag = [result integerValue] >= 1? YES : NO;

dispatch_semaphore_signal(sema);
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
else
{
NSString * hasVideoTestString = @"document.documentElement.getElementsByTagName(\"video\").length";
NSString * result = [self stringByEvaluatingJavaScriptFromString:hasVideoTestString];
hasVideoTag = [result integerValue] >= 1? YES : NO;
}

return hasVideoTag;
}
-(NSString *)getVideoTitle
{
__block NSString * title = nil;

if (![[NSThread currentThread] isMainThread])
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);

dispatch_async(dispatch_get_main_queue(), ^{
NSString *currentURL = [self stringByEvaluatingJavaScriptFromString:@"document.location.href"];
title = [self stringByEvaluatingJavaScriptFromString:@"document.title"];
NSLog(@"++++ URL:%@",currentURL);
NSLog(@"++++ title:%@", title);

dispatch_semaphore_signal(sema);
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
else
{
NSString *currentURL = [self stringByEvaluatingJavaScriptFromString:@"document.location.href"];
title = [self stringByEvaluatingJavaScriptFromString:@"document.title"];
NSLog(@"++++ URL:%@",currentURL);
NSLog(@"++++ title:%@", title);
}

return title;
}
- (double)getVideoDuration
{
__block double duration = 0;

if ([self hasVideo])
{
if (![[NSThread currentThread] isMainThread])
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);

dispatch_async(dispatch_get_main_queue(), ^{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].duration.toFixed(1)";
NSString * result = [self stringByEvaluatingJavaScriptFromString:requestDurationString];
NSLog(@"+++ Web Video Duration:%@",result);
duration = [result doubleValue];

dispatch_semaphore_signal(sema);
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
else
{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].duration.toFixed(1)";
NSString * result = [self stringByEvaluatingJavaScriptFromString:requestDurationString];
NSLog(@"+++ Web Video Duration:%@",result);
duration = [result doubleValue];
}
}

return duration;
}
- (double)getVideoCurrentTime
{
__block double currentTime = 0;

if ([self hasVideo])
{
if (![[NSThread currentThread] isMainThread])
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);

dispatch_async(dispatch_get_main_queue(), ^{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].currentTime.toFixed(1)";
NSString * result = [self stringByEvaluatingJavaScriptFromString:requestDurationString];
NSLog(@"+++ Web Video CurrentTime:%@",result);
currentTime = [result doubleValue];

dispatch_semaphore_signal(sema);
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
else
{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].currentTime.toFixed(1)";
NSString * result = [self stringByEvaluatingJavaScriptFromString:requestDurationString];
NSLog(@"+++ Web Video CurrentTime:%@",result);
currentTime = [result doubleValue];
}
}

return currentTime;
}

- (int)play
{
if ([self hasVideo])
{
if (![[NSThread currentThread] isMainThread])
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);

dispatch_async(dispatch_get_main_queue(), ^{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].play()";
[self stringByEvaluatingJavaScriptFromString:requestDurationString];

dispatch_semaphore_signal(sema);
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
else
{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].play()";
[self stringByEvaluatingJavaScriptFromString:requestDurationString];
}
}
return 0;
}
- (int)pause
{
if ([self hasVideo])
{
if (![[NSThread currentThread] isMainThread])
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);

dispatch_async(dispatch_get_main_queue(), ^{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].pause()";
[self stringByEvaluatingJavaScriptFromString:requestDurationString];

dispatch_semaphore_signal(sema);
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
else
{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].pause()";
[self stringByEvaluatingJavaScriptFromString:requestDurationString];
}
}
return 0;
}
- (int)resume
{
if ([self hasVideo])
{
if (![[NSThread currentThread] isMainThread])
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);

dispatch_async(dispatch_get_main_queue(), ^{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].play()";
[self stringByEvaluatingJavaScriptFromString:requestDurationString];

dispatch_semaphore_signal(sema);
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
else
{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].play()";
[self stringByEvaluatingJavaScriptFromString:requestDurationString];
}
}
return 0;
}
- (int)stop
{
if ([self hasVideo])
{
if (![[NSThread currentThread] isMainThread])
{
dispatch_semaphore_t sema = dispatch_semaphore_create(0);

dispatch_async(dispatch_get_main_queue(), ^{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].pause()";
[self stringByEvaluatingJavaScriptFromString:requestDurationString];

dispatch_semaphore_signal(sema);
});
dispatch_semaphore_wait(sema, DISPATCH_TIME_FOREVER);
}
else
{
NSString * requestDurationString = @"document.documentElement.getElementsByTagName(\"video\")[0].pause()";
[self stringByEvaluatingJavaScriptFromString:requestDurationString];
}
}

return 0;
}

@end