iphone - 设置委托(delegate)导致崩溃

Question

我从 UIViewController 调用 NSObject，并将 View Controller 设置为 NSObject 的委托(delegate)。

当执行此代码时，由于 EXC_BAD_ACCESS，应用程序在模拟器 上完全崩溃(这在这里如何应用？)。当应用程序在真实设备上运行时，应用程序在第三次执行代码时崩溃。真实设备日志输出如下:

(First time)
2012-04-01 13:29:05.154 The Record[19044:707] Done

----
(Second time)
2012-04-01 13:29:06.274 The Record[19044:707] Done

----
(Third time)
2012-04-01 13:29:07.772 The Record[19044:707] -[ViewController setDelegate:]: unrecognized selector sent to instance 0xde2e6e0
2012-04-01 13:29:07.773 The Record[19044:707] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[ViewController setDelegate:]: unrecognized selector sent to instance 0xde2e6e0'
*** First throw call stack:
(0x3211088f 0x37515259 0x32113a9b 0x32112915 0x3206d650 0x537f7 0x4f82b 0x3206a3fd 0x379eafaf 0x37ab076b 0x3206a3fd 0x379eafaf 0x379eaf6b 0x379eaf49 0x379eacb9 0x379eb5f1 0x379e9ad3 0x379e94c1 0x379cf83d 0x379cf0e3 0x3144322b 0x320e4523 0x320e44c5 0x320e3313 0x320664a5 0x3206636d 0x31442439 0x379fde7d 0x4dd8d 0x4dd38)
terminate called throwing an exception(lldb)

我只是调用 NSObject 并将 View Controller 设置为委托(delegate)。

Authorization *authorization = [[Authorization alloc] init];
authorization.delegate = self;

当我取出 authorization.delegate = self; 时，应用程序不会崩溃，但我显然需要那一行。

编辑:这是代码。我正在使用 @protocol。授权.h:

#import <Foundation/Foundation.h>
#import "KeychainItemWrapper.h>

@protocol AuthorizationDelegate <NSObject>
- (void)done:(BOOL *)done downloadURL:(NSURL *)downloadURL username:(NSString *)username password:(NSString *)password reason:(NSString *)reason;
@end

@interface Authorization : NSObject {

    id<AuthorizationDelegate> delegate;
    KeychainItemWrapper *keychain;

}

-(id)init;

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

@end

----
//Authorization.m

#import "Authorization.h"
#import "ASIFormDataRequest.h"
#import "JSON.h"

@implementation Authorization

@synthesize delegate;

-(id)init {

    keychain = [[KeychainItemWrapper alloc] initWithIdentifier:@"exampleID" accessGroup:nil];
    NSString *passPhrase = [keychain objectForKey:(id)kSecValueData];


    // Start request
    NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"https://www.website.com/authorization.php"]];
    ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:url];
    [request setPostValue:passPhrase forKey:@"passphrase"];
    [request setPostValue:@"YES" forKey:@"receivingAuthorization"];
    [request setDidFinishSelector:@selector(requestFinished:)];
    [request setDidFailSelector:@selector(requestFailed:)];
    [request setDelegate:self];
    [request startAsynchronous];

}

-(void)requestFinished:(ASIHTTPRequest *)request {

    if (request.responseStatusCode == 200) {

        NSString *responseString = [request responseString];
        NSDictionary *responseDict = [responseString JSONValue];
        NSString *downloadString = [responseDict objectForKey:@"downloadURL"];
        NSString *username = [responseDict objectForKey:@"username"];
        NSString *password = [responseDict objectForKey:@"password"];

        if ((downloadString != nil) && (username != nil) && (password != nil)) {

            NSURL *downloadURL = [NSURL URLWithString:downloadString];

            [delegate done:YES downloadURL:downloadURL username:username password:password reason:@"Received Authorization"];

         } else {

            [delegate done:NO downloadURL:nil username:nil password:nil reason:@"Invalid Request"];

        }

    } else if (request.responseStatusCode == 400) {

        if ([[request responseString] compare:@"Invalid passphrase"] == 0) {

            [delegate done:NO downloadURL:nil username:nil password:nil reason:@"Incorrect Credentials"];

        } else if ([[request responseString] compare:@"Invalid request"] == 0) {

            [delegate done:NO downloadURL:nil username:nil password:nil reason:@"Invalid Request"];

        }

    } else {

        [delegate done:NO downloadURL:nil username:nil password:nil reason:@"Invalid Request"];

    }

}

@end


----

//ViewController.h

@interface ViewController : UIViewController <IssuesPickerDelegate, IssueTableDelegate, AuthorizationDelegate> {

    Authorization *authorization;

}

@property (nonatomic, retain) Authorization *authorization;

----

//ViewController.m

@synthesize authorization;

-(void)done:(BOOL *)done downloadURL:(NSURL *)downloadURL username:(NSString *)username password:(NSString *)password reason:(NSString *)reason {

NSLog(@"Done");

if ((done == YES) && ([reason compare:@"Received Authorization"] == 0)) {


} else if ([reason compare:@"Incorrect Credentials"] == 0) {

    Login *login = [[Login alloc] init];

}

}


-(void)getAuthorization {

//this part here causes the crash

authorization = [[Authorization alloc] init];
authorization.delegate = self;

}

Answer 1

我忘记从 -(id)init 返回一个值。我正在返回 self。我的新 -(id)init 代码如下。

-(id)init {

    self = [super init];

    keychain = [[KeychainItemWrapper alloc] initWithIdentifier:@"exampleID" accessGroup:nil];
    NSString *passPhrase = [keychain objectForKey:(id)kSecValueData];         

    // Start request
    NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:@"https://www.website.com/authorization.php"]];
    ASIFormDataRequest *request = [ASIFormDataRequest requestWithURL:url];
    [request setPostValue:passPhrase forKey:@"passphrase"];
    [request setPostValue:@"YES" forKey:@"receivingAuthorization"];
    [request setDidFinishSelector:@selector(requestFinished:)];
    [request setDidFailSelector:@selector(requestFailed:)];
    [request setDelegate:self];
    [request startAsynchronous];

    return self;

}