Question

我有两个ViewControllers：A和B，

我在A中计算B的变量，然后通过创建ViewController B的对象来推动B的变量值.B的变量本身是声明的。现在我在ViewController B中更改变量的值并返回到A.我想在A中使用变量的变量值。我已经尝试了协议，但在A中我得到该变量的0值。这是我的代码：

ViewController A.h

#import <UIKit/UIKit.h>
#import "B.h"
@class B;
@interface ViewController : UIViewController<nxtDelegate>
{
int vcheck;
 }
@property(nonatomic,assign) int vcheck;

实施A：

#import "ViewController.h"

@interface ViewController ()

 @end

@implementation ViewController
@synthesize lbl,txt,vcheck;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
    // Custom initialization
}
return self;
}

-(void)viewWillAppear:(BOOL)animated{
NSLog(@"vcheckis:%d",vcheck);

}
-(void)chngvalue:(int)i{
vcheck=i;
}

ViewController B.h

#import <UIKit/UIKit.h>

@protocol nxtDelegate <NSObject>

-(void)chngvalue:(int )i;

@end
@interface nextviewController :   UIViewController<UITableViewDelegate,UIPickerViewDelegate,UIPickerViewDataSource>
{
int chcek;
}
@property(weak,nonatomic)id<nxtDelegate> delegate;
- (IBAction)btnclick:(id)sender;
@property(nonatomic,assign) int chcek;

ViewController B.m

- (IBAction)chngAction:(id)sender {
[_delegate chngvalue:chcek];
NSLog(@"%@",_delegate);}

Answer 1

我不知道为什么它不起作用，但我只是按照下面的说法进行操作

@property(nonatomic, assign)id<nxtDelegate> Delegate;

合成属性名称Delegate

@synthesize Delegate;

并且在推送期间我设置了委托

ViewControllerB *ViewControllerBObj=[[ViewControllerB alloc] init];
[ViewControllerBObj setDelegate:self];
[[self navigationController] pushViewController:ViewControllerBObj animated:YES];

在IBAction中

- (IBAction)chngAction:(id)sender 
{
    if([[self Delegate] respondsToSelector:@selector(chngvalue:)])
      [[self Delegate] chngvalue:chcek];
}

如何使用Protocol在两个视图控制器之间传递值

1 个答案: