Dropbox定义了自己的URI方案， dbapi-1 ，因此您可以看到操作系统是否可以使用该方案打开URL，如下所示： / p>

Dropbox define their own URI scheme, dbapi-1, and as such you can see if the OS can open URLs using that scheme, as so:

if ([[UIApplication sharedApplication] canOpenURL:[NSURL URLWithString:@"dbapi-1://"]]) {
    NSLog(@"Dropbox is installed.");
} else {
    NSLog(@"Dropbox is not installed.");
}