Ios NSdateFormatter在缩短日期后返回null

我试图以MM/dd格式显示tweets的日期，但返回null。longDate很好，并以这种长格式显示正确的日期

NSDate *createdDate = [NSDate dateWithTimeIntervalSince1970:[[[sortedEvents objectAtIndex:indexPath.row] objectForKey:@"created_time"] doubleValue]];
NSString *dateString = [NSString stringWithFormat:@"%@", createdDate];
[dateFormat setDateFormat:@"yyyy-MM-dd HH:mm:ss ZZZ"];
NSDate *longDate = [dateFormat dateFromString: dateString];

[dateFormat setDateFormat:@"MM/dd"];
NSString *dateString2 = [NSString stringWithFormat:@"%@", longDate];
NSDate *condensedDate = [dateFormat dateFromString:dateString2];

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你有几个不必要的步骤。既然你是以日期开始的，就这样做：

NSDate *createdDate = [NSDate dateWithTimeIntervalSince1970:[[[sortedEvents objectAtIndex:indexPath.row] objectForKey:@"created_time"] doubleValue]];
[dateFormat setDateFormat:@"MM/dd"];
NSString *condensedString = [dateFormat stringFromDate:longDate];

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您不需要来回查看所有其他内容。

您可能应该查找模板而不是格式。