设置日期期限的时候下面这个方法用不了(升级成ios7之后)

 NSDate *toDate =[[NSDate alloc]initWithString:@"2000-10-10 12:00:00 -0500"];

用下面的方法替换

    NSDateFormatter * formatter = [[NSDateFormatter alloc]init];

    [formatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

    NSString * mindateStr = @"1900-01-01 00:00:00";

    NSString * maxdateStr = @"2099-01-01 00:00:00";

    NSDate * mindate = [formatter dateFromString:mindateStr];

    NSDate * maxdate = [formatter dateFromString:maxdateStr];

    datepiker = [[UIDatePickeralloc]initWithFrame:CGRectMake(0,40, 320,180)];

    datepiker.datePickerMode =UIDatePickerModeDate;//设置日期显示格式

    datepiker.minimumDate = mindate;

    datepiker.maximumDate = maxdate;

    datepiker.backgroundColor = [UIColor  whiteColor];