目标c-用Xcode实现decimal-through(id)sender标记

Question

我有一个简单的iOS/objective C问题。我已经搜索了论坛，并尝试了几种不同的方法，但我似乎无法理解，我对编码很陌生，所以我很抱歉这可能看起来很愚蠢。我正试图用从头开始制作的按钮制作一个简单的计算器，但我被小数部分卡住了。我使用switch语句通过按钮（id）发件人输入我的号码。你可以看到我注释掉的部分，这就是我要用10标记id的地方，并写一些语句来实现浮点值中的小数。

我还看了以前的一篇文章，它把小数点后加了一位。我试着修改代码，但这里似乎遗漏了很多东西。

-(IBAction)decimalButton:(id)sender{
    calculatorScreen.text = [calculatorScreen.text stringByAppendingFormat:@"."]; 
}

任何帮助/建议/示例代码都将非常有帮助，再次，我对新手的问题感到抱歉，我正在尽我所能学习基础知识。

#import "calcViewController.h"
@implementation calcViewController

-(IBAction)buttonDigitPressed:(id)sender { //ditits presed with sender tag
//    switch ([sender tag]) {
//        case 1:
//            currentNumber = 1;
//            break;
//        case 2:
//            currentNumber = 2;
//            break;
//        case 3:
//            currentNumber = 3;
//            break;
//        case 4:
//            currentNumber = 4;
//            break;
//        case 5:
//            currentNumber = 5;
//            break;
//        case 6:
//            currentNumber = 6;
//            break;
//        case 7:
//            currentNumber = 7;
//            break;
//        case 8:
//            currentNumber = 8;
//            break;
//        case 9:
//            currentNumber = 9;
//            break;
//        case 10:
//            //possibly implement decimal here 
//            break;
//    }

    currentNumber = (float)[sender tag]; //sets currentNumber to buttonPressed
    calculatorScreen.text = [NSString stringWithFormat:@"%g",currentNumber];//displays button
}

-(IBAction)buttonOperationPressed:(id)sender {
    //currentOperation is 0 by system default?
    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;
    currentNumber = result; //current number equals last resulting equation
    calculatorScreen.text = [NSString stringWithFormat:@"%g",result]; //screen prints result
    if ([sender tag] == 0) result = 0;
    currentOperation = [sender tag];
}

Answer 1

下面的代码应该会正确更新屏幕。

-(IBAction)buttonDigitPressed:(id)sender { //ditits presed with sender tag
    switch ([sender tag]) {
        case 1:
        case 2:
        case 3:
        case 4:
        case 5:
        case 6:
        case 7:
        case 8:
        case 9:
            calculatorScreen.text = [calculatorScreen.text stringByAppendingFormat:@"%d", [sender tag]];
            break;
        case 10:
            NSRange range = [calculatorScreen.text rangeOfString:@"."];
            if ( range.location == NSNotFound ) {
                calculatorScreen.text = [calculatorScreen.text stringByAppendingString:@"."];
            }
            break;
    }
}

要在计算中使用此项，请使用

float screenNumber = [calculatorScreen.text floatValue];