我正在尝试制作一个计算器应用程序，但是当我按下回车键时，没有任何东西被推入数组。我有一个定义方法的类CaculatorBrain，但是（现在）我在视图控制器中pushElement定义并实现了方法。pushElement
当我按下输入键时在控制台中键入操作数对象时，数组的内容为零！这是为什么？
#import "CalculatorViewController.h"
#import "CalculatorBrain.h"
@interface CalculatorViewController ()
@property (nonatomic)BOOL userIntheMiddleOfEnteringText;
@property(nonatomic,copy) NSMutableArray* operandStack;
@end
@implementation CalculatorViewController
BOOL userIntheMiddleOfEnteringText;
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}
-(NSMutableArray*) operandStack {
if (_operandStack==nil) {
_operandStack=[[NSMutableArray alloc]init];
}
return _operandStack;
}
-(CalculatorBrain*)Brain
{
if (!_Brain) _Brain= [[CalculatorBrain alloc]init];
return _Brain;
}
- (IBAction)digitPressed:(UIButton*)sender {
if (self.userIntheMiddleOfEnteringText) {
NSString *digit= [sender currentTitle];
NSString *currentDisplayText=self.display.text;
NSString *newDisplayText= [currentDisplayText stringByAppendingString:digit];
self.display.text=newDisplayText;
NSLog(@"IAm in digitPressed method");
}
else
{
NSString *digit=[sender currentTitle];
self.display.text = digit;
self. userIntheMiddleOfEnteringText=YES;
}
}
-(void)pushElement:(double)operand {
NSNumber *operandObject=[NSNumber numberWithDouble:operand];
[_operandStack addObject:operandObject];
NSLog(@"operandObject is %@",operandObject);
NSLog(@"array contents is %@",_operandStack);
}
- (IBAction)enterPressed {
[self pushElement: [self.display.text doubleValue] ];
NSLog(@"the contents of array is %@",_operandStack);
userIntheMiddleOfEnteringText= NO;
}