比如A,B兩個view，值從A傳到B。在B里面寫A *av = [[A alloc]init];[av setDelegate:self]和在A里面寫B *bv = [[B alloc]init];[self setDelegate:bv];這句setDelegate要放哪里呢？viewDidLoad？沒有報錯，但是就是傳值不成功。能給我一點提示嗎？代碼#import <Foundation/Foundation.h>@protocol delegate <NSObject>-(void)passString:(NSString *)string;@end#import <UIKit/UIKit.h>#import "labelViewController.h"#import "delegate.h"@interface buttonViewController : UIViewController @property (weak, nonatomic) IBOutlet UIButton *button;@property (weak,nonatomic) id <delegate> delegate; - (IBAction)buttonPress:(UIButton *)sender;@end#import "buttonViewController.h"@interface buttonViewController ()@end@implementation buttonViewController- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];    if (self) {        // Custom initialization     }    return self; } - (void)viewDidLoad { labelViewController *lv = [[labelViewController alloc]init]; [self setDelegate:lv];         [super viewDidLoad]; // Do any additional setup after loading the view.} - (IBAction)buttonPress:(UIButton *)sender { [self.delegate passString:sender.currentTitle]; [self performSegueWithIdentifier:@"push" sender:self]; }@end#import <UIKit/UIKit.h>#import "delegate.h"@interface labelViewController : UIViewController <delegate>@property (weak, nonatomic) IBOutlet UILabel *label;@end#import "labelViewController.h"@interface labelViewController ()@end@implementation labelViewController- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];    if (self) {        // Custom initialization     }    return self; } - (void)viewDidLoad {     [super viewDidLoad];    // Do any additional setup after loading the view.} - (void)passString:(NSString *)string{ self.label.text = string; NSLog(@"%@",self.label.text); }@end