如果是Xcode 4.6 ,那么按照下面的方法添加：
解决方案：
从91SDK3.2.5开始要求接入方需要设置一个URL Scheme，设置方法如下：选中工程中的Target，选中Info标签页，找到底下的URL Types，展开，点击加号，创建一个新的URL Scheme。
171300xkniiaxbbnwq9yzy.png.thumb.jpg
点击后，Identifier字段填入你的软件标识符，URL Schemes字段填入格式为：91-xxxxx，其中xxxx为你的软件标识符。Role字段可以设置为None，Icon字段可以不填。示例如下：
1713376wx166ne1r66aqw6.png
2. 然后 在主动设备的应用程序A中，通过 这个方法判断手机中是否存在这个应用B
[[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString"XXX://"]];
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如果返回YES则表示此应用在手机中安装过，反之则没有安装过.
具体代码如下：
-(BOOL) APCheckIfAppInstalled2:(NSString *)urlSchemes
{
if ([[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:urlSchemes]])
{
NSLog(@" installed");
return YES;
}
else
{
return NO;
}
}
调用 APCheckIfAppInstalled2:XXX 就可以判断 是否安装了应用程序B 了。
这个方法不管对越狱过的iOS设备还是没有越狱过的设备都生效。
还有另外一个 查看
com.apple.mobile.installation.plist 系统文件的方法，通过 bundle identifier 来判断，但是只能判断越狱机，因为越狱机才能访问到这个文件，在非越狱的机器中，因为不允许应用程序访问沙盒环境以外的目录，所以不能读取这个文件，甚至判断这个文件是否存在都会失败。
代码如下：
-(BOOL) APCheckIfAppInstalled:(NSString *)bundleIdentifier
{
static NSString *const cacheFileName = @"com.apple.mobile.installation.plist";
NSString *relativeCachePath = [[@"Library" stringByAppendingPathComponent: @"Caches"] stringByAppendingPathComponent: cacheFileName];
NSDictionary *cacheDict = nil;
NSString *path = nil;
// Loop through all possible paths the cache could be in
for (short i = 0; 1; i++)
{
switch (i)
{
case 0: // Jailbroken apps will find the cache here; their home directory is /var/mobile
path = [NSHomeDirectory() stringByAppendingPathComponent: relativeCachePath];
break;
case 1: // App Store apps and Simulator will find the cache here; home (/var/mobile/) is 2 directories above sandbox folder
path = [[NSHomeDirectory() stringByAppendingPathComponent: @"../.."] stringByAppendingPathComponent: relativeCachePath];
break;
case 2: // If the app is anywhere else, default to hardcoded /var/mobile/
path = [@"/var/mobile" stringByAppendingPathComponent: relativeCachePath];
break;
default: // Cache not found (loop not broken)
return NO;
break;
}
BOOL isDir = NO;
if ([[NSFileManager defaultManager] fileExistsAtPath: path isDirectory: &isDir] ) // Ensure that file exists
{
if (isDir == YES)
{
NSLog(@"Dir");
}
else
{
cacheDict = [NSDictionary dictionaryWithContentsOfFile: path];
}
}
if (cacheDict) // If cache is loaded, then break the loop. If the loop is not "broken," it will return NO later (default: case)
break;
}
NSDictionary *system = [cacheDict objectForKey: @"System"]; // First check all system (jailbroken) apps
if ([system objectForKey: bundleIdentifier])
return YES;
NSDictionary *user = [cacheDict objectForKey: @"User"]; // Then all the user (App Store /var/mobile/Applications) apps
if ([user objectForKey: bundleIdentifier])
return YES;
// If nothing returned YES already, we'll return NO now
return NO;
}