Objective c 3个文本框和一个计算按钮

我有3个文本框和一个计算按钮，我如何才能告诉按钮开关文本框被选中，并转换成其他文本框的数字，我已经标记了文本框1，2和3，我是非常新的和绿色的编程，所以任何帮助将是伟大的。 这是我的密码

- (IBAction)Calculate:(id)sender {
    NSNumberFormatter *numberFormatter = [[NSNumberFormatter alloc] init];

    float a = [[numberFormatter numberFromString:_Barrels.text] floatValue];
    float b = [[numberFormatter numberFromString:_Gallons.text] floatValue];
    float c = [[numberFormatter numberFromString:_Liters.text] floatValue];


    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", a];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", a * 42];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", a * 159];

    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", b * .0238];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", b];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", b * 3.785];

    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", c * .0063];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", c * .264];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", c];

    switch ([sender tag]) {
        case 1:
            [_Barrels resignFirstResponder];
            [_Gallons resignFirstResponder];
            [_Liters resignFirstResponder];
            break;
        default:
            break;
    } 

---

在ViewController.h文件中使用一个变量/标志来存储最后选择的文本字段

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController<UITextFieldDelegate>
{
    int textfieldFlag;
}

@end

那么在乌尔

 - (IBAction)Calculate:(id)sender
{
   //ABove Code....   

    if(textfieldFlag==1){
    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", a];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", a * 42];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", a * 159];
   }
if(textfieldFlag==2){
    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", b * .0238];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", b];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", b * 3.785];
   }
if(textfieldFlag==3){
    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", c * .0063];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", c * .264];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", c];
   }

   //Below Code...

}

相应地使用

textfieldFlag

---

textfieldFlag

将包含上次选择/编辑的textfield的标志

当您点击计算按钮时，必须调用此方法：

-（void）textfieldDendediting:（UITextField*）textfield

。在这里，通过检查tagValue来确定编辑了哪个文本字段，并据此进行计算。请确保添加文本字段的代理，否则-（void）textfielddidediting将不会被调用。

您是否有可能在我的代码中设置此选项，以便我可以看到它，我只是在这里遇到了很多错误：/对不起，我的回答很糟糕。。int textField=0；在.h中是错误的，请查看编辑过的答案OK，它现在正在运行，但是如果我在其中一个文本框中输入一个数字，然后在其他文本框中单击“计算无任何内容”，您知道可能有什么问题吗？检查您是否已为文本字段设置了委托，并且正在调用

textFieldDidBeginEditing

方法。

 - (IBAction)Calculate:(id)sender
{
   //ABove Code....   

    if(textfieldFlag==1){
    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", a];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", a * 42];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", a * 159];
   }
if(textfieldFlag==2){
    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", b * .0238];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", b];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", b * 3.785];
   }
if(textfieldFlag==3){
    _Barrels.text = [[NSString alloc]initWithFormat:@"% .2f", c * .0063];
    _Gallons.text = [[NSString alloc]initWithFormat:@"% .2f", c * .264];
    _Liters.text = [[NSString alloc]initWithFormat:@"% .2f", c];
   }

   //Below Code...