检查 iphone 是否安装某 app

转载自：http://blog.csdn.net/zengconggen/article/details/7714514

        开发中遇到一个问题：公司多个产品时，希望在一个产品A中可以直接打开另外的某个产品B。如果用户尚未安装产品B， 则打开app store下载页面。

          对于这个问题：有3个技术点：

        1、产品B是否已安装的检测。

         2、应用内打开其他app的技术：参考：https://developer.apple.com/library/IOs/#documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/AdvancedAppTricks/AdvancedAppTricks.html#//apple_ref/doc/uid/TP40007072-CH7-SW18

         3、从应用跳转至app下载页面的技术：参考：http://blog.csdn.net/zengconggen/article/details/6789420

         对于第2、3点，本文略过不讲。现提供第1技术点方案：（说明：技术有风险，有可能导致app被拒。不过app store有类似上线作品。看RP）

解决方案1：(经验证：该方案真机ios5无效，模拟器可以)

// Declaration
BOOL APCheckIfAppInstalled(NSString *bundleIdentifier); // Bundle identifier (eg. com.apple.mobilesafari) used to track apps

// Implementation

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] && !isDir) // Ensure that file exists
            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;
}

解决方案2：参考：http://blog.csdn.net/zengconggen/article/details/7714466

本方案有限制：只能获取到用户最近运行过的app。对于已安装但是不在最近有运行的app。不适用。

解决方案3：

BOOL isExsit = [[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:@"rumtel://com.rumtel.AudioManager"]];
NSLog(@"App %@ installed", identifier);
if (isExsit)
{
    [[UIApplication sharedApplication] openURL:[NSURL URLWithString:@"rumtel://com.rumtel.AudioManager?a=1&b=2#sect"]];
}
else
{
    //打开app store下载页面
}

方案3需要知道B的打开地址。可用。最终方案确定为3

附：目前公开的app相关资料：http://wiki.akosma.com/IPhone_URL_Schemes