Question

我是一名新程序员，了解IOS和Objective C编程的基础知识，但遇到了一个错误。

我要做的就是点击一个按钮时，它会调用另一个类的方法。

我试图调用的方法是：[phoneCompany printPrompt];

所以这是我的代码：

头等舱:( ViewController）

的.m

    #import "ViewController.h"
#import "PhoneCompany.h"

@implementation ViewController

@synthesize dialTextField;
@synthesize dialButton;
@synthesize textFromCall;


- (void)viewDidLoad
{
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];

    self.dialTextField = [[UITextField alloc]initWithFrame:CGRectMake(83, 101, 154, 30)];
    self.dialTextField.borderStyle = UITextBorderStyleRoundedRect;
    self.dialTextField.placeholder = @"Dial Number";
    self.dialTextField.textAlignment = NSTextAlignmentCenter;
    self.dialTextField.adjustsFontSizeToFitWidth = YES;
    self.dialTextField.minimumFontSize = 20;
    self.dialTextField.autocorrectionType = NO;
    self.dialTextField.returnKeyType = UIReturnKeyDone;
    self.dialTextField.backgroundColor = [UIColor lightGrayColor];
    self.dialTextField.delegate = self;
    [self.view addSubview:self.dialTextField];

    self.dialButton= [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [self.dialButton setTitle:@"Dial!" forState:UIControlStateNormal];
    self.dialButton.titleLabel.font = [UIFont systemFontOfSize:20];
    [self.dialButton setBackgroundColor:[UIColor blueColor]];
    [self.dialButton setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [self.dialButton addTarget:self action:@selector(mainCall) forControlEvents:UIControlEventTouchUpInside];
    self.dialButton.frame =CGRectMake(92, 400, 125, 30);
    [self.view addSubview:self.dialButton];

    self.textFromCall = [[UILabel alloc]initWithFrame:CGRectMake(48,155,220,240)];
    [self.textFromCall setText:@"Hello, what number would you like to call?"];
    self.textFromCall.numberOfLines = 0;
    self.textFromCall.lineBreakMode = UILineBreakModeWordWrap;
    self.textFromCall.adjustsFontSizeToFitWidth = YES;
    [self.textFromCall setTextAlignment:NSTextAlignmentCenter];
    [self.textFromCall setTextColor:[UIColor blackColor]];
    [self.textFromCall setBackgroundColor:[UIColor clearColor]];
    [self.view addSubview: self.textFromCall];
}


-(void) mainCall{

    if([self.dialTextField.text isEqualToString:@"1234567"]){

        self.dialButton.enabled = NO;
        self.dialTextField.enabled = NO;

        PhoneCompany *phoneCompany = [[PhoneCompany alloc]init];


        [NSTimer scheduledTimerWithTimeInterval: 3 target:phoneCompany selector:@selector(printPrompt)
                                       userInfo:nil repeats:NO];

        self.textFromCall.text = @"Dialing...";
       [NSTimer scheduledTimerWithTimeInterval: 1 target:self selector:@selector(connectingStatement)
                                       userInfo:nil repeats:NO];



}

else if([self.dialTextField.text isEqualToString: nil]){
        self.textFromCall.text = @"Please enter a phone number.";
    }

    else{
        self.textFromCall.text = @"Invalid Phone number.";
    }
}

-(void)connectingStatement{
    self.textFromCall.text = @"Connecting...";
}


-(BOOL) textFieldShouldReturn:(UITextField *)textField{

    [textField resignFirstResponder];
    return YES;
}




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

@end

.h

#import <UIKit/UIKit.h>

@interface ViewController : UIViewController

@property (nonatomic) UITextField *dialTextField;
@property (weak,nonatomic) UIButton *dialButton;
@property (strong,nonatomic) UILabel *textFromCall;

-(void) mainCall;
-(void) connectingStatement;
-(void) setString:(NSString *)string;

@end

现在是第二类:( PhoneCompany）

·H

#import <Foundation/Foundation.h>

@interface PhoneCompany : NSObject

-(void) printPrompt;


@end

的.m

#import "PhoneCompany.h"
#import "ViewController.h"

@implementation PhoneCompany

-(void) printPrompt{

    ViewController *mainView = [[ViewController alloc]init];
    mainView.dialTextField.text = @"Test";

}

@end

Answer 1

您对printPrompt的调用很好。问题是您正在函数中创建一个新的ViewContoller。您在printPrompt中创建的那个与您调用该函数的那个不同。我的意思是setString：不会替换textFromCall文本字段的文本。不知何故，您需要将ViewController作为委托传递给PhoneCompany，并从中调用setString：。

编辑：

试试这个 -

在PhoneCompany.h中

@class PhoneCompany;

@protocol PhoneCompanyDelegate <NSObject>

-(void)phoneCompany:(PhoneCompany *)phoneCompay
          setString:(NSString *)string;

@end

@interface PhoneCompany : NSObject

@property (nonatomic, assign)id<PhoneCompanyDelegate>delegate;

- (id)initWithDelegate:(id<PhoneCompanyDelegate>)delegate;
- (void) printPrompt;

@end

在PhoneCompay.m

中

@implementation PhoneCompany

- (id)initWithDelegate:(id<PhoneCompanyDelegate>)delegate
{
    self = [super init];

    if (self)
    {
        self.delegate = delegate;
    }

    return self;
}


-(void) printPrompt
{
    if (self.delegate && [self.delegate respondsToSelector:@selector(phoneCompany:setString:)])
    {
        [self.delegate phoneCompany:self
                          setString:@"Test"];
    }
}

@end

在prinPrompt

中创建PhonCompany对象时

PhoneCompany *phoneCompay = [[PhoneCompany alloc] initWithDelegate:self];

在ViewController.h中

#import "PhoneCompany"

@interface ViewController:UIViewController<PhoneCompanyDelegate>

Answer 2

事实证明，我所要做的就是将textFromCall声明为静态UILabel * textFromCall，然后声明一种编辑文本的方法。谢谢你的所有答案！

为什么我的方法调用不是从另一个类开始工作？

2 个答案: