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 ie (+,- ,c) 工作了一次并且从未工作过，因为它们只返回 Nan 和 inf 并且输入按钮总是使应用程序崩溃并返回下面的错误。我在情节提要中构建 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;
}
@结尾
我从一个示例开始工作并遵循所有步骤我不明白我做错了什么 enterPressed 方法没有类型，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)
任何帮助将不胜感激