Question

这是主要想法

+---MyViewController.m----+                        +---BtnOnClickResp.m-----+
|                         |  EventTouchUpInside:   |                        |  
|       Button ---------------------------------------> OnBtnClick()        |
|                         | textView.text=@"blabla"|         |              |
|      *textView <------------------------------------------ +              |
|                         |                        |                        |
+-------------------------+                        +------------------------+

我想测试是否可以在另一个控制器中按下按钮OnClick，如下所示：

MyViewController.h

#import <UIKit/UIKit.h>

@interface MyViewController : UIViewController

@property (nonatomic, strong) UITextView *textView;

+(id) sharedInstance;

@end

MyViewController.m

#import "MyViewController.h"
#import "BtnOnClickResp.h"

@interface MyViewController ()

@end

@implementation MyViewController

@synthesize textView;

+ (id) sharedInstance{
    static MyViewController *instance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        instance = [[self alloc] init];
    });
    return instance;
}

- (void) setUpScene{
    textView = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, 500, 400) ];
    [textView setBackgroundColor:[UIColor grayColor]];
    [textView setFont:[UIFont systemFontOfSize:18]];
    [textView setTextColor:[UIColor blackColor]];
    textView.text = @"";
    [self.view addSubview:textView];
    UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(100, 50 , 400, 50)];
    [btn setTitle:@"Click Me" forState:UIControlStateNormal];
    [btn setBackgroundColor:[UIColor yellowColor]];
    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [btn addTarget:[[BtnOnClickResp alloc] init] action:@selector(onBtnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
}


- (void)viewDidLoad {
    [super viewDidLoad];
    [self setUpScene];
    // Do any additional setup after loading the view.
}

@end

BtnOnClickResp.h

#import <UIKit/UIKit.h>

@interface BtnOnClickResp : UIViewController

@end

BtnOnClickResp.m

#import "BtnOnClickResp.h"
#import "MyViewController.h"

@interface BtnOnClickResp ()

@end

@implementation BtnOnClickResp

- (void) onBtnClick: (UIButton *) btn{
    NSLog(@"btn was click but I am in another controller");
    MyViewController *control = [MyViewController sharedInstance];
    control.textView.text = @" I am setting this content in another view cheers!!!";
}

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}

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


@end

主要的想法是在MyViewController中绘制/添加一个按钮视图并在另一个控制器中点击代码做出响应，我想到了动作分配代码：

[btn addTarget:self action:@selector(onBtnClick:) forControlEvents:UIControlEventTouchUpInside];

如果我们将self更改为我们想要使用的实际控制器，则会将click事件分派给该控制器

但似乎没有用。

如果你不打算回答这个初学者的问题，那么ios开发的初学者会很高兴。

EIDT

在接受@Mike建议后的建议后，

我将MyViewController.m更改为：

#import "MyViewController.h"
#import "BtnOnClickResp.h"

@interface MyViewController (){
    //here is the change , I made a private ref of the controller
    BtnOnClickResp *respContl;
}

@end

@implementation MyViewController

@synthesize textView;

+ (id) sharedInstance{
    static MyViewController *instance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        instance = [[self alloc] init];
    });
    return instance;
}

- (void) setUpScene{
    textView = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, 500, 400) ];
    [textView setBackgroundColor:[UIColor grayColor]];
    [textView setFont:[UIFont systemFontOfSize:18]];
    [textView setTextColor:[UIColor blackColor]];
    textView.text = @"";
    [self.view addSubview:textView];
    UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(100, 50 , 400, 50)];
    [btn setTitle:@"Click Me" forState:UIControlStateNormal];
    [btn setBackgroundColor:[UIColor yellowColor]];
    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [btn addTarget:respContl action:@selector(onBtnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
}


- (void)viewDidLoad {
    respContl = [[BtnOnClickResp alloc] init];
    [super viewDidLoad];
    [self setUpScene];
    // Do any additional setup after loading the view.
}

@end

现在我可以看到btn was click but I am in another controller的NSLog，但视图内容仍未保持@" I am setting this content in another view cheers!!!"，因为它预期位于BtnOnClickResp.m

这是AppDelagate.m

中的启动代码

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {

    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];

    UIViewController *control = [[MyViewController alloc] init];
    [self.window setRootViewController:control];
    [self.window setBackgroundColor:[UIColor greenColor]];
    [self.window makeKeyAndVisible];
    // Override point for customization after application launch.
    return YES;
}

Answer 1

您正在添加目标

[btn addTarget:[[BtnOnClickResp alloc] init] action:@selector(onBtnClick:) forControlEvents:UIControlEventTouchUpInside];

到

[BtnOnClickResp alloc] init]

错了

因为它会创建新实例并为其添加侦听器。但是，您尝试访问其他实例中的操作

你有4个解决方案

创建BtnOnClickResp的共享实例并为其指定目标
将self的{{1}}传递给BtnOnClickResp并分配
创建代表
发布通知

Answer 2

声明BtnOnClickResp的属性并将其设置为按钮目标。

#import "MyViewController.h"
#import "BtnOnClickResp.h"

@interface MyViewController ()

@property(nonatomic, strong) BtnOnClickResp onClickRespObj;
@end

@implementation MyViewController

@synthesize textView;

+ (id) sharedInstance{
    static MyViewController *instance = nil;
    static dispatch_once_t onceToken;
    dispatch_once(&onceToken, ^{
        instance = [[self alloc] init];
    });
    return instance;
}

- (id)init{
    if(self = [super init]){
    self.onClickRespObj = [[BtnOnClickResp alloc] init];
    }
    return self;
}

- (void) setUpScene{
    textView = [[UITextView alloc] initWithFrame:CGRectMake(0, 0, 500, 400) ];
    [textView setBackgroundColor:[UIColor grayColor]];
    [textView setFont:[UIFont systemFontOfSize:18]];
    [textView setTextColor:[UIColor blackColor]];
    textView.text = @"";
    [self.view addSubview:textView];
    UIButton *btn = [[UIButton alloc] initWithFrame:CGRectMake(100, 50 , 400, 50)];
    [btn setTitle:@"Click Me" forState:UIControlStateNormal];
    [btn setBackgroundColor:[UIColor yellowColor]];
    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
    [btn addTarget:self.onClickRespObj action:@selector(onBtnClick:) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:btn];
}


- (void)viewDidLoad {
    [super viewDidLoad];
    [self setUpScene];
    // Do any additional setup after loading the view.
}

@end

IOS响应按钮单击另一个viewController

EIDT

2 个答案: