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我正在制作一个转换器应用程序，在意识到我必须输入大约 200 行代码才能让它处理超过 5 个转换单位后，我应该有一个更好的转换计算。

我目前拥有的是一个 ifelse，它可以找出我从轮子中选择的单位，找出它应该回答什么的刺痛以及要计算的浮点数。它看起来像这样的自动取款机：

 #import "MainViewController.h"
@interface MainViewController ()

@end

@implementation MainViewController;

@synthesize _convertFrom, _convertTo, _convertRates;
@synthesize inputText, picker, resultLabel;
- (void)viewDidLoad
{
    [super viewDidLoad];
    {
        [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
        _convertFrom = @[@"MTPA", @"MMcf/day",
        @"Mill.Sm3/day", @"MMBTU", @"Boe/day"];

        _convertRates = @[ @1.0f, @2.0f, @3.0f,
        @4.0f, @5.0f];

        _convertTo = @[@"MTPA", @"MMcf/day",
        @"Mill.Sm3/day", @"MMBTU", @"Boe/day"];

    _convertRates = @[ @1.0f, @2.0f, @3.0f,
    @4.0f, @5.0f];
}
}
- (void)didReceiveMemoryWarning
{
 [super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
//dont forget to put something in here later
}


-(IBAction)textFieldReturn:(id)sender
{
    [sender resignFirstResponder];
}
-(IBAction)backgroundTouched:(id)sender
{
    [inputText resignFirstResponder];
}


#pragma mark -
#pragma mark PickerView DataSource

- (NSInteger)numberOfComponentsInPickerView:
(UIPickerView *)pickerView
{
    return 2;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:    (NSInteger)component
{
    if (component == 0)  {
        return [_convertFrom count];
    }
    return [_convertTo count];
}


- (NSString *) pickerView: (UIPickerView *)pickerView
          titleForRow:(NSInteger)row
         forComponent:(NSInteger)component
{
    if (component == 0) {
        return [_convertFrom objectAtIndex:row];
    }
    return [_convertTo objectAtIndex:row];
}




#pragma mark -
#pragma mark PickerView Delegate
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row
  inComponent:(NSInteger)component
{
    float convertFrom = [[_convertRates objectAtIndex:[pickerView selectedRowInComponent:0]] floatValue];
    float convertTo = [[_convertRates objectAtIndex:[pickerView selectedRowInComponent:1]] floatValue];
    float input = [inputText.text floatValue];
float to = convertTo;
float from = convertFrom;
float convertValue = input;

float MTPATilMTPAFloat               = convertValue * 1;
float MTPATilMMScfdayFloat           = convertValue * 133.425;
float MTPATilMillSm3dayFloat         = convertValue * 3.779735;
float MTPATilMMBTUFloat              = convertValue * 4;
float MTPATilboedayFloat               = convertValue * 5;

float MMScfdayTilMTPAFloat           = convertValue * 0.5;
float MMScfdayTilMMScfdayFloat       = convertValue * 1;
float MMScfdayTilMillSm3dayFloat     = convertValue * 6;
float MMScfdayTilMMBTUFloat          = convertValue * 7;
float MMScfdayTilboedayFloat           = convertValue * 8;

float MillSm3dayTilMTPAFloat = convertValue / 1;
float MillSm3dayTilMMScfdayFloat = convertValue / 2;
float MillSm3dayTilMillSm3dayFloat = convertValue / 3;
float MillSm3dayTilMMBTUFloat = convertValue / 4;
float MillSm3dayTilboedayFloat = convertValue / 5;

float MMBTUTilMTPAFloat = convertValue * 2;
float MMBTUTilMMScfdayFloat = convertValue * 2;
float MMBTUTilMillSm3dayFloat = convertValue * 2;
float MMBTUTilMMBTUFloat = convertValue * 2;
float MMBTUTilboeday = convertValue * 2;

float boedayTilMTPAFloat = convertValue * 3;
float boedayTilMMScfdayFloat = convertValue * 3;
float boedayTilMillSm3dayFloat = convertValue * 3;
float boedayTilMMBTUFloat = convertValue * 3;
float boedayTilboeday = convertValue * 3;





NSString *MTPATilMTPA = [[NSString alloc ] initWithFormat:
                         @" %f MTPA = %f MTPA", convertValue, MTPATilMTPAFloat];

NSString *MTPATilMMScfday = [[NSString alloc ] initWithFormat:
                             @" %f MTPA = %f MMScf/day", convertValue, MTPATilMMScfdayFloat];

NSString *MTPATilMillSm3day = [[NSString alloc] initWithFormat:
                               @" %f MTPA = %f Mill.SM3/day", convertValue, MTPATilMillSm3dayFloat];

NSString *MTPATilMMBTU = [[NSString alloc] initWithFormat:
                          @" %f MTPA = %f MMBTU", convertValue, MTPATilMMBTUFloat];

NSString *MTPATilboeday = [[NSString alloc] initWithFormat:
                         @" %f MTPA = %f Boe/day", convertValue, MTPATilboedayFloat];




NSString *MMScfdayTilMTPA = [[NSString alloc] initWithFormat:
                             @" %f MMScfday = %f MTPA", convertValue, MMScfdayTilMTPAFloat];

NSString *MMScfdayTilMMScfday = [[NSString alloc] initWithFormat:
                                 @" %f MMScfday = %f MMScfday", convertValue, MMScfdayTilMMScfdayFloat];

NSString *MMScfdayTilMillSm3day = [[NSString alloc] initWithFormat:
                                   @" %f MMScfday = %f MillSm3day", convertValue, MMScfdayTilMillSm3dayFloat];

NSString *MMScfdayTilMMBTU = [[NSString alloc] initWithFormat:
                              @" %f MMScfday = %f MMBTU", convertValue, MMScfdayTilMMBTUFloat];

NSString *MMScfdayTilboeday = [[NSString alloc] initWithFormat:
                             @" %f MMScfday = %f Boe/day", convertValue, MMScfdayTilboedayFloat];




NSString *MillSm3dayTilMTPA = [[NSString alloc] initWithFormat:
                               @" %f MillSm3day = %f MTPA", convertValue, MillSm3dayTilMTPAFloat];



if (from == 1) {
    if (to == 1) {
        resultLabel.text = MTPATilMTPA;
    }
    else if (to == 2) {
        resultLabel.text = MTPATilMMScfday;
    }
    else if (to == 3) {
        resultLabel.text = MTPATilMillSm3day;
    }
    else if (to == 4) {
        resultLabel.text = MTPATilMMBTU;
    }
    else if (to == 5) {
        resultLabel.text = MTPATilboeday;
    }
}
else if (from == 2) {
    if (to == 1) {
        resultLabel.text = MMScfdayTilMTPA;
    }
    else if (to == 2) {
        resultLabel.text = MMScfdayTilMMScfday;
    }
    else if (to == 3) {
        resultLabel.text = MMScfdayTilMillSm3day;
    }
    else if (to == 4) {
        resultLabel.text = MMScfdayTilMMBTU;
    }
    else if (to == 5) { 
        resultLabel.text = MMScfdayTilboeday;
    }
}
}

如您所见，如果我想要更多单元，则需要大量代码。

当我意识到这一点时，我尝试使用一个常用变量来计算它，我将所有内容都转换为该变量，然后再转换回输出单元。用长度计算来考虑它。我希望首先将所有内容转换为的公共变量是米。所以 1 米 = 1、1 厘米 = 0.01 和 1 毫米 = 0.001。所以，如果我想计算，我会使用。

unitIwantToConvertToComparedTo1Meter = 0.5（1 米）结果 = 从 * 到 * 输入 * unitIwantToConvertToComparedTo1Meter。

令人惊讶的是，这很有效。在这里使用：

#import "MainViewController.h"
@interface MainViewController ()

@end

@implementation MainViewController;

@synthesize _convertFrom, _convertTo, _convertRates;
@synthesize inputText, picker, resultLabel;
- (void)viewDidLoad
{
    [super viewDidLoad];
    {
        [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
        _convertFrom = @[@"Kubikk M", @"Kubikk CM",
        @"Kubikk MM", @"MMBTU", @"Boe/day"];

        _convertRates = @[ @1.0f, @0.01f, @0.001f,
        @4.0f, @5.0f];

    _convertTo = @[@"Kubikk M", @"Kubikk CM",
    @"Kubikk MM", @"MMBTU", @"Boe/day"];

    _convertRates = @[ @1.0f, @0.01f, @0.001f,
    @4.0f, @5.0f];
}
}
- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
//dont forget to put something in here later
}


    -(IBAction)textFieldReturn:(id)sender
    {
    [sender resignFirstResponder];
}
-(IBAction)backgroundTouched:(id)sender
{
    [inputText resignFirstResponder];
}


#pragma mark -
#pragma mark PickerView DataSource

- (NSInteger)numberOfComponentsInPickerView:
(UIPickerView *)pickerView
{
    return 2;
}

- (NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component
{
if (component == 0)  {
    return [_convertFrom count];
}
return [_convertTo count];
}


- (NSString *) pickerView: (UIPickerView *)pickerView
          titleForRow:(NSInteger)row
         forComponent:(NSInteger)component
{
    if (component == 0) {
        return [_convertFrom objectAtIndex:row];
    }
    return [_convertTo objectAtIndex:row];
}




#pragma mark -
#pragma mark PickerView Delegate
-(void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row
  inComponent:(NSInteger)component
{
    float convertFrom = [[_convertRates objectAtIndex:[pickerView   selectedRowInComponent:0]] floatValue];
float convertTo = [[_convertRates objectAtIndex:[pickerView selectedRowInComponent:1]] floatValue];
float input = [inputText.text floatValue];
float to = convertTo;
float from = convertFrom;
float convertValue = input;

float kubikkfot = 0.1;

float result = from * convertValue * kubikkfot;



NSString *resultString = [[NSString alloc ] initWithFormat:
                         @" %f MTPA = %f MTPA", convertValue, result];
resultLabel.text = resultString;
}

这个问题是 1. 我的大脑正在崩溃，试图弄清楚如何 2. 我想为每个答案都有一个自定义标签，上面写着我转换的单位。我该如何实施？

那么，任何人都可以帮我提供一些更好的计算代码吗？

4

1 回答 1

2

Dude 使用 C 数组创建一个 nxn 转换矩阵。然后只有一个带有单位名称的数组。做完了。如果您不知道矩阵是什么，那么您需要学习更多的理论。

它是这样的。C 是您的转换矩阵：

       inch      meter
      +-----------------
inch  | 1        0.0254
meter | 39.3701  1

因此，如果x以英寸为单位，则以C[inch][meter] * x米为单位的长度相同。

和C[i][j] * C[j][i] == 1。总是。

对于要测量的每个数量，您将有一个不同的转换矩阵。也就是说，你会有一个热量，一个时间，一个距离（上面的例子），一个能量，一个力量......等等。祝你好运！

于 2012-10-14T13:56:54.237 回答