iphone - 如何根据 objective-c 计算安装的应用和设备日期之间的日期计数差

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Number of days between two NSDates [duplicate]
                                
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如何计算目标C格式的两天之间的日期计数差异。

最佳答案

检查安装日期是否已注册，如果已注册，则计算日期，否则进行注册。

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];
}