查看对象无法连接到文件所有者

Question

我试图在视图中"连接"我的对象File's Owner使用interface builder,但蓝线不与它"链接".这是我的代码:

CalculatorViewController.h:

#import <UIKit/UIKit.h>
#import "CalculatorBrain.h"

@interface CalculatorViewController : UIViewController {
    IBOutlet UILabel *display;
    IBOutlet UIButton *button;
    CalculatorBrain *brain;
    BOOL userIsInTheMiddleOfTypingANumber;
}

- (IBAction)digitPressed: (UIButton *)sender;
- (IBAction)operationPressed: (UIButton *)sender;

@end

CalculatorViewController.m:

#import "CalculatorViewController.h"

@implementation CalculatorViewController

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


- (IBAction)digitPressed:(UIButton *)sender
{
    NSString *digit = [[sender titleLabel] text];
    if (userIsInTheMiddleOfTypingANumber) {
        [display setText: [[display text] stringByAppendingString:digit]];
    } else {
        [display setText:digit];
        userIsInTheMiddleOfTypingANumber = YES;
    }
}

- (IBAction)operationPressed: (UIButton *)sender 
{
    if (userIsInTheMiddleOfTypingANumber) {
        [[self brain] setOperand: [[display text] doubleValue]];
        userIsInTheMiddleOfTypingANumber = NO;
    }
    NSString *operation = [[sender titleLabel] text];
    double result = [[self brain] performOperation:operation];
    [display setText: [NSString stringWithFormat: @"%g", result]];
}
@end  

Answer 1

尝试检查文件所有者的类是否在XIB中正确设置为ViewController类.

用于检查转到您的XIB

单击文件所有者并打开检查器.

在检查器中,转到最后一个(第四个)选项卡,检查是否已将类设置为 <yourViewControllerName>

希望这对你有所帮助.

编辑:

为了更好地理解,我添加了一个您需要查找课程的图像.

另请检查您是否IBOutlet在ViewController的头文件中使用Prefix 声明了变量