iphone - 如何从 Objective-C 计算我的应用程序安装日期和设备日期之间的日期计数差异

Question

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Answer 1

检查安装日期是否注册，如果注册则计算日期，否则注册。

if([[NSUserDefaults standardUserDefaults] objectForKey:@"IDate"])
{
    NSDate *iDate = [[NSUserDefaults standardUserDefaults] objectForKey:@"IDate"];
    NSTimeInterval interval = [[NSDate date] timeIntervalSinceDate:iDate];
    int diff=interval/86400;//for converting seconds into days.
    NSLog(@"%d Days",diff);
}
else
{
    [[NSUserDefaults standardUserDefaults] setObject:[NSDate date] forKey:@"IDate"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}