Question

想象一下，你有一个名为A的UITableView。

在A中，您实现了一个委托方法来打印通过名为B的详细视图控制器中定义的协议传递给它的数据。

在A的A.m实现文件中，您有以下代码：

#import "A.h"
#import "B.h"

@interface A()
@end

@implementation

//bunch of methods not relevant to this question first

//Implement method that passes myStringData sent back from B to A
#pragma mark - Send data back to cell tapped in feed

-(void)sendDataBackToA:(NSString *)myStringData 
{
if ([myStringData rangeOfString:@"Ciao_Bello"].location == NSNotFound)
   {
    NSLog(@"The string delegate back to A in case 1 is %@", myStringData); 
   }

else
   {
   NSLog(@"The string delegate back to A in case 2 is %@", myStringData); 
   }

}

在B.h标题中，您声明相关协议和委托：

@protocol senddataProtocol <NSObject>
-(void)sendDataBackToA:(NSString)myStringData
@end

@interface B: UIViewController<UIPopoverPresentationControllerDelegate, UIAdaptivePresentationControllerDelegate>
@property(nonatomic, assign)id<senddataProtocol> stringDelegate;
@end

实现B.m时，确保合成您的委托属性并在viewWillDisappear中调用委托方法，打印您传递的NSString：

@implementation B
@synthesize stringDelegate;

//A few methods' implementations not relevant to this questions first

//Call delegate method to pass data from B to A in viewWillDisappear
-(void)viewWillDisappear:(BOOL)animated
{
   if ([self.button.titleLabel.text rangeOfString:@"text1"].location == NSNotFound)

   {
    [stringDelegate sendDataBackToA:@"Ciao_Bello"];
    NSLog(@"The string delegate sent from B to A is %@", @"Ciao_Bello");
   }

else
   {
    [[stringDelegate sendDataBackToA:@"Forza_Italia"];
    NSLog(@"The string delegate sent from B to A is %@", @"Forza_Italia");
   }
}

然后你运行你的构建。

根据为B中的按钮设置的NSString值（self.button.titleLabel.text），您会看到@“Ciao_Bello”和@“Forza_Italia”在您的日志中正确打印，这取决于为B中的按钮设置的NSString值。

但是你也在你的日志中看到，从未在A中调用sendDataBackToA委托方法。

你需要做些什么来解决这个问题？

谢谢！

UITableView中的Delegate方法在详细信息视图中通过协议将数据传递给它后不会调用

0 个答案: