如何访问其他类中的对象？

IR Works 发表于 Dev

投资者关系工作

我想从ViewController 2访问ViewController 1中的一个函数。此方法有效（由断点和NSLog输出确认）。但是从ViewController 2调用时，访问在ViewController 1中定义的对象为nil。

ViewController 1.h

#import "SRWebSocket.h"

@interface ViewController : UIViewController <UITextFieldDelegate, SRWebSocketDelegate> 
@property (nonatomic,strong) SRWebSocket *socket;

-(void)sendMessageToServerWithContent:(NSString *)message;

ViewController 1.m

- (IBAction)connect:(id)sender {

    socket.delegate = nil;
    socket = nil;

    socket = [[SRWebSocket alloc] initWithURLRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:serverIP_GLOBAL]]];

    socket.delegate = self;

}

-(void)sendMessageToServerWithContent:(NSString *)message{

//irrelevant code for question removed
[self.socket send:jsonString];

}

ViewController 2.h

#import "ViewController.h"

@property (nonatomic,strong) ViewController *viewVC;
@interface ContactsTableViewController : UITableViewController

ViewController 2.m

- (void)viewDidLoad {
    [super viewDidLoad];

    viewVC = [ViewController alloc];

    [viewVC sendMessageToServerWithContent:@"Test"]; 
    //When calling from here, the socket object in ViewController 1 is nil

}

吉里耶什·库玛（Girijesh Kumar）

您不能像这样初始化对象： viewVC = [ViewController alloc];

您必须将ViewContoller1的对象传递给ViewContoller2，即

在viewcontoller1上推动ViewContoller2时，您已编写了情节提要删除代码

 - (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
    {

        ViewController2 *view2=[segue destinationViewController];
        view2.viewVC=self; // pass viewcontoller1 object to viewcontoller2
    }

在ViewContoller2中，您将在viewVC变量中访问viewContoller1对象，您可以像这样直接调用它

- (void)viewDidLoad {

    [super viewDidLoad];
    [viewVC sendMessageToServerWithContent:@"Test"]; 
    //When calling from here, the socket object in ViewController 1 is nil

}

本文收集自互联网，转载请注明来源。

如有侵权，请联系[email protected] 删除。