IOS的​​UIViewController繼承引發的重複符號錯誤

Question

我有所有的子類的單一方法我想提供一個父視圖控制器：

#import "GAViewController.h" 

@interface GAViewController()<UITextFieldDelegate> 

@end 

@implementation GAViewController 


#pragma mark - UITextFieldDelegate 

- (BOOL)textFieldShouldReturn:(UITextField *)textField 
{ 
    [textField resignFirstResponder]; 
    return YES; 
} 


@end 

我有一個看起來像這樣的寄存器視圖控制器：

//.h 
    #import <UIKit/UIKit.h> 
    #import "GAViewController.h" 
    #import "GAViewController.m" 

    @interface GARegisterViewController : GAViewController 

    @end 

//.m 
#import "GARegisterViewController.h" 


@interface GARegisterViewController()<UIActionSheetDelegate, UINavigationControllerDelegate, UIImagePickerControllerDelegate, UIGestureRecognizerDelegate> 
@property (weak, nonatomic) IBOutlet UIButton *registerButton; 
@property (weak, nonatomic) IBOutlet UITextField *userNameTextField; 
@property (weak, nonatomic) IBOutlet UITextField *passwordTextField; 
@property (weak, nonatomic) IBOutlet UITextField *firstNameTextField; 
@property (weak, nonatomic) IBOutlet UITextField *lastNameTextField; 
@property (weak, nonatomic) IBOutlet UITextField *phoneNumberTextField; 
@property (weak, nonatomic) IBOutlet UISegmentedControl *genderSegmentedContoller; 

@end 

@implementation GARegisterViewController 

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil 
{ 
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil]; 
    if (self) { 
     // Custom initialization 
    } 
    return self; 
} 

- (void)viewDidLoad 
{ 
    [super viewDidLoad]; 

    [self makeTextFieldDelegates]; 
} 

- (void)makeTextFieldDelegates{ 
    [self.userNameTextField setDelegate:self]; 
    [self.passwordTextField setDelegate:self]; 
    [self.firstNameTextField setDelegate:self]; 
    [self.lastNameTextField setDelegate:self]; 
    [self.phoneNumberTextField setDelegate:self]; 
} 

- (void)didReceiveMemoryWarning 
{ 
    [super didReceiveMemoryWarning]; 
    // Dispose of any resources that can be recreated. 
} 

@end 

這是我收到的錯誤：

有誰知道我可以修復上面的錯誤？或者使用textFieldShoudlReturn方法正確創建一個父類，以便我不必在所有視圖中都包含該類。

謝謝！

Answer 1

我進口的.m，因爲它包含了textfieldshouldreturn方法，它也進口.h文件

它是進口，導致重複的符號.m文件。導入.m文件會導致導入它的文件將包含的.m文件定義爲相同的符號（例如方法實現和具有外部範圍的函數/變量），從而導致重複。

出於同樣的原因，不應該將@implementation塊放到頭文件中。

爲了解決這個問題，請爲GAViewController製作標題，並在其中聲明textFieldShouldReturn:。從頭文件和.m文件中刪除#import "GAViewController.m"，替換爲#import "GAViewController.h"。這應該解決這個問題。