Question

可能重复：
  How do I change the number of decimal places iOS?
  If using Xcode to make an iOS calculator, how would I add a decimal button?

我正在寻找一个关于如何制作（简单）iPhone计算器的iOS教程，该计算器至少可以执行以下操作：加，减，乘，除，并让用户输入小数点。我无法找到这样的教程，所以如果有人知道，请告诉我。我确实找到了一个你可以加，减，乘，除，但不能做小数点的地方。如果您可以告诉我如何让用户输入小数点，则无需进一步的教程。我现在使用的代码如下。

头文件中的

：

#import <UIKit/UIKit.h>

@interface CalculatorViewController : UIViewController {

float result;
IBOutlet UILabel *calculatorScreen;
int currentOperation;
float currentNumber;

}


-(IBAction)buttonDigitPressed:(id)sender;
-(IBAction)buttonOperationPressed:(id)sender;
-(IBAction)cancelInput;
-(IBAction)cancelOperation;

在主文件中：

#import "CalculatorViewController.h"

@implementation CalculatorViewController


-(IBAction)buttonDigitPressed:(id)sender {


currentNumber = currentNumber *10 + (float)[sender tag];
calculatorScreen.text = [NSString stringWithFormat:@"%.1f", currentNumber];

}

-(IBAction)buttonOperationPressed:(id)sender {
if (currentOperation ==0) result = currentNumber;
else {        

    switch (currentOperation) {
        case 1:
            result = result + currentNumber;
            break;
        case 2:
            result = result - currentNumber;
            break;
        case 3:
            result = result * currentNumber;
            break;
        case 4:
            result = result / currentNumber;
            break;
        case 5:
            currentOperation = 0;
            break;

    }
}

currentNumber = 0;
calculatorScreen.text = [NSString stringWithFormat:@"%.1f", result];
if ([sender tag] ==0) result=0;
currentOperation = [sender tag];
}



-(IBAction)cancelInput {

currentNumber =0;
calculatorScreen.text = @"0";

 }


-(IBAction)cancelOperation {



currentNumber = 0;
calculatorScreen.text = @"0";
currentOperation = 0;

}

Answer 1

这应该有效。简单直接。

更改了currentNumber以存储正在进行的计算的当前字符串值（Make this NSMutableString），为小数点按钮添加了一个插座（buttonDecialPointPressed）。

-(IBAction) buttonDigitPressed:(id)sender
{
    currentNumber = [currentNumber appendFormat:@"%d"];
    calculatorScreen.text = currentNumber;
}

- (IBAction) buttonDecialPointPressed:(id)sender
{
    if(behindTheDecimal == YES)
        return;
    behindTheDecimal = YES;
    currentNumber = [currentNumber appendString:@"."];
    calculatorScreen.text = currentNumber;
}

-(IBAction)buttonOperationPressed:(id)sender
{
    float number = [currentNumber floatValue];
    switch (currentOperation)
    {
        case 0:
            result = number;
            break;
        case 1:
            result = result + number;
            break;
        case 2:
            result = result - number;
            break;
        case 3:
            result = result * number;
            break;
        case 4:
            result = result / number;
            break;
        case 5:
            currentOperation = 0;
            break;
        case 6:
            break;
    }

    currentNumber = [currentNumber stringWithFormat:@"%f", result];
    calculatorScreen.text = currentNumber;

    // why is this needed, how is it used?
    currentOperation = [sender tag];
}


-(IBAction)cancelInput
{
    behindTheDecimal = NO;
    currentNumber = @"0";
    calculatorScreen.text = currentNumber;  
}

-(IBAction)cancelOperation
{
    behindTheDecimal = NO;
    currentNumber = @"0";
    calculatorScreen.text = currentNumber;
    currentOperation = 0;
}

带小数点的iPhone计算器教程

1 个答案: