Question

我在xcode 4.5中构建了这个计算器应用程序，数字按预期工作，但操作即（+， - ，c）工作一次，因为它们只返回Nan和inf而且输入按钮总是崩溃应用程序并返回错误我在故事板中构建了UI，并将按钮链接到相关方法

@autoreleasepool {
    return UIApplicationMain(argc, argv, nil, NSStringFromClass([CalculatorAppDelegate     
class]));

这是我的CalculatorViewController.h

#import <UIKit/UIKit.h>

@interface CalculatorViewController : UIViewController
@property (weak, nonatomic) IBOutlet UILabel *display;

@end

这是我的CalculatorViewController.m

#import "CalculatorViewController.h"
#import "CalculatorBrain.h"

@interface CalculatorViewController ()
@property(nonatomic) BOOL userIsInTheMidleOfEnteringANumber;
@property (nonatomic, strong)CalculatorBrain *brain;
@end

@implementation CalculatorViewController

@synthesize display = _display;
@synthesize userIsInTheMidleOfEnteringANumber =_userIsInTheMidleOfEnteringANumber;
@synthesize brain = _brain;

- (CalculatorBrain *)brain
{
     if (!_brain)_brain=[[CalculatorBrain alloc]init];
return _brain;
}

- (IBAction)digitPressed:(UIButton *)sender
{
    NSString *digit = sender.currentTitle;
    if (self.userIsInTheMidleOfEnteringANumber){
    self.display.text = [self.display.text stringByAppendingString:digit];
}
    else {
        self.display.text = digit;
        self.userIsInTheMidleOfEnteringANumber=YES;
    }
}
- (IBAction)enterPressed
{
    NSLog(@"im hre");
    [self.brain pushOperand:[self.display.text doubleValue]];
    self.userIsInTheMidleOfEnteringANumber=NO;
}
- (IBAction)operationPresed:(UIButton *)sender
{
    if (self.userIsInTheMidleOfEnteringANumber) [self enterPressed];
    double result =[self.brain performOperation:sender.currentTitle];
    NSString *resultString= [NSString stringWithFormat:@"%g",result];
    self.display.text= resultString;
}
    @end

这是我的CalculatorBrain.h

#import <Foundation/Foundation.h>

@interface CalculatorBrain : NSObject
-(void)pushOperand:(double)operand;
-(double)performOperation:(NSString *)operation;

@end

这是我的CalculatorBrain.m

#import "CalculatorBrain.h"
@interface CalculatorBrain()
@property (nonatomic,strong)NSMutableArray *operandStack;
@end

@implementation CalculatorBrain
@synthesize operandStack = _operandStack;

-(NSMutableArray *)operandStack
{
    if (_operandStack== nil) _operandStack =[[NSMutableArray alloc] init];
    return _operandStack;
}

-(void)pushOperand:(double)operand
{

    [self.operandStack addObject:[NSNumber numberWithDouble:operand]];
}
-(double)popOperand
{
    NSNumber *operandObject = [self.operandStack lastObject];
    if (operandObject) [self.operandStack removeLastObject];
    return [operandObject doubleValue];
}

-(double)performOperation:(NSString *)operation
{
     double result=0;
    //calculate result
    if ([operation isEqualToString:@"+"])
    {
        result =[self popOperand]+ [self popOperand];
    }
    else if ([operation isEqualToString:@"*"])
    {
    result = [self popOperand] *  [self popOperand];
    }
    else if ([operation isEqualToString:@"-"]) {
        result = [self popOperand] - [self popOperand];
    }
    else if ([operation isEqualToString:@"/"]) {
        result = [self popOperand] / [self popOperand];
    } 
     [self pushOperand:result];

    return result;
}

@end

我正在从一个例子工作并且已经按照所有步骤我不明白我做错了什么我没有输入类型，即UIButton这是我的控制台输出

2013-05-17 15:05:15.221 Calculator[786:11303] im hre
2013-05-17 15:05:15.280 Calculator[786:11303] -[CalculatorViewController enterPressed:]: unrecognized selector sent to instance 0x922a620
2013-05-17 15:05:15.288 Calculator[786:11303] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[CalculatorViewController enterPressed:]: unrecognized selector sent to instance 0x922a620'
*** First throw call stack:
(0x1c8e012 0x10cbe7e 0x1d194bd 0x1c7dbbc 0x1c7d94e 0x10df705 0x16920 0x168b8 0xd7671 0xd7bcf 0xd6d38 0x4633f 0x46552 0x243aa 0x15cf8 0x1be9df9 0x1be9ad0 0x1c03bf5 0x1c03962 0x1c34bb6 0x1c33f44 0x1c33e1b 0x1be87e3 0x1be8668 0x1365c 0x1f0d 0x1e35)
libc++abi.dylib: terminate called throwing an exception
(lldb)

任何帮助都会受到赞赏

Answer 1

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[CalculatorViewController enterPressed:]: unrecognized selector sent to instance 0x922a620'就是答案。检查您的enterPressed:课程中是否有CalculatorViewController方法。我确定如果没有丢失，它会以某种方式拼写错误

Answer 2

更改方法签名：

- (IBAction)enterPressed

到

- (IBAction)enterPressed:(id)sender

Answer 3

在 CalculatorViewController.m 文件中替换

- (IBAction)enterPressed

到

- (IBAction)enterPressed:(UIButton *)sender

Answer 4

我实际上遇到了同样的问题...我删除了Enter按钮并重新创建它然后它工作了。祝你好运，我想把头发拉出来

Answer 5

下面有许多工作答案。您遇到此问题的原因是，您在xib文件中链接的方法与xib上的某个按钮相关联，指向enterPressed: - 带参数的方法（enterPressed后跟冒号），但是您编写了一个没有参数的方法（enterPressed），因此会导致崩溃。代码试图找到一个带有你在xib文件中链接的参数的方法，但它没有找到它，导致崩溃说 - '无法识别的选择器发送到实例' < /强>

因此只需替换

- (IBAction)enterPressed

用这个：

- (IBAction)enterPressed:(UIButton *)sender

SIGABRT错误崩溃的应用程序

5 个答案: