将 NSString 转换为 NSDecimalNumber

Posted 2023-03-14

【中文标题】将 NSString 转换为 NSDecimalNumber

【英文标题】：Convert NSString to NSDecimalNumber

【发布时间】：2013-01-17 03:45:22

【问题描述】：

在我的核心数据模型中，“数量”是实体“跟踪”中的一个属性。如何在整个代码中将金额转换为 NSDecimalNumber？我确信有更多经验的人可以在 3 分钟内完成这项工作，而我已经研究了好几天了。

- (IBAction)save 
if (![amount.text isEqualToString:@""]) 
Tracking *tracking = [NSEntityDescription insertNewObjectForEntityForName:@"Tracking"
                                               inManagedObjectContext:self.managedObjectContext];

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *weightEntity = [NSEntityDescription entityForName:@"Tracking" inManagedObjectContext:self.managedObjectContext];
    [fetchRequest setEntity:weightEntity];
    NSSortDescriptor *sortDescriptor = [NSSortDescriptor sortDescriptorWithKey:@"timestamp" ascending:NO];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sortDescriptor]];

    NSError *error = nil;
    NSArray *result = [self.managedObjectContext executeFetchRequest:fetchRequest error:&error];

    Tracking *person = [result objectAtIndex:0];

    NSLog(@"%@",person.date);

        NSDate *date = [NSDate date];
    NSDateFormatter *dateFormat = [[NSDateFormatter alloc]init];
    [dateFormat setDateFormat:@"MMM dd, yyyy"];

    NSString *dateString = [dateFormat stringFromDate:date];
    //NSString *dateString = @"Jan 13 2013";
    //Tracking *track = [self.fetchedResultsController objectAtIndexPath:nil];

tracking.note = note.text;
tracking.amount = amount.text;
tracking.title = [segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex];
tracking.date = dateString;
tracking.timestamp = date;

        if (![person.date isEqualToString:dateString]) 

        if ([[segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex] isEqualToString:@"Food/Drink"]) 
            tracking.pic = @"Drink";
            tracking.total = [NSString stringWithFormat:@"%.2f", 0.00 - [amount.text floatValue]];
            NSLog(@"%f",[person.total floatValue]);
            NSLog(@"%f", [amount.text floatValue]);
            //tracking.total = @"1000.00";
        
        else if ([[segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex] isEqualToString:@"Other"]) 
            tracking.total = [NSString stringWithFormat:@"%.2f",0.00 - [amount.text floatValue]];
            tracking.pic = [segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex];

        

        else 
            tracking.pic = [segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex];
            tracking.total = [NSString stringWithFormat:@"%.2f",0.00 + [amount.text floatValue]];
        

    

    else 


        if ([[segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex] isEqualToString:@"Food/Drink"]) 
            tracking.pic = @"Drink";
            tracking.total = [NSString stringWithFormat:@"%.2f",[person.total floatValue] - [amount.text floatValue]];
            NSLog(@"%f",[person.total floatValue]);
            NSLog(@"%f", [amount.text floatValue]);
    //tracking.total = @"1000.00";
            
        else if ([[segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex] isEqualToString:@"Other"]) 
            tracking.total = [NSString stringWithFormat:@"%.2f",[person.total floatValue] - [amount.text floatValue]];
            tracking.pic = [segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex];

        

        else 
            tracking.pic = [segmentedChoice titleForSegmentAtIndex:segmentedChoice.selectedSegmentIndex];
            tracking.total = [NSString stringWithFormat:@"%.2f",[person.total floatValue] + [amount.text floatValue]];

        
    

NSLog(@"\n Title: %@ \n Amount: %@ \n Note: %@ \n Date: %@ \n Picture: %@.png \n Total: %@ \n TimeStamp: %@", tracking.title, tracking.amount, tracking.note,tracking.date,tracking.pic, tracking.total, tracking.timestamp);

   [self.managedObjectContext save:nil];

   /* UIAlertView *alert = [[UIAlertView alloc] initWithTitle:[NSString stringWithFormat:@"%@ Saved",tracking.title] message:[NSString stringWithFormat:@"Amount: %@ \n Note: %@",tracking.amount,tracking.note] delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
    [alert show];*/

    [amount resignFirstResponder];
    [note resignFirstResponder];
    [self dismissViewControllerAnimated:YES completion:nil];

【参考方案1】：

NSDecimalNumber 有以下方法可以用来将你的 NSString 转换成它：

+ (NSDecimalNumber *)decimalNumberWithString:(NSString *)numericString

例如：

NSString *foo = @"1.0";
NSDecimalNumber *cow = [NSDecimalNumber decimalNumberWithString:foo];

该课程的完整参考可在此处获得：http://developer.apple.com/library/mac/#documentation/Cocoa/Reference/Foundation/Classes/NSDecimalNumber_Class/Reference/Reference.html#//apple_ref/occ/cl/NSDecimalNumber

【讨论】：

使用[cow doubleValue]取回原来的值。

【参考方案2】：

给你：

NSString *order; 
NSDecimalNumber *decimal = [NSDecimalNumber decimalNumberWithString:order];

【讨论】：

嗨，我的字符串是 @"12.30" 然后它返回 12.3 它删除零我不想删除零我该怎么做，请帮助我。谢谢

Hii 尝试这种方式，但它与修复小数分数一起使用我想要动态的，所以我该怎么做。？还要检查这个***.com/questions/56004505/…