Question

这是我第一次使用Iphoneapp进行编码，而且我在弄清楚我在做错了什么时遇到了一些困难。

我有2个视图控制器：viewController和viewController2我从viewController调用viewcontroller2来设置一些参数并在viewController中访问它们。

我使用委托模式，如下所示：

在viewController2.h中

#import <UIKit/UIKit.h>

@protocol ViewController2Delegate
-(void)setVideoQual:(NSInteger)quality; 
@end


@interface ViewController2 : UIViewController


@property (nonatomic, retain) id delegate;
@property IBOutlet UISegmentedControl *videoQuality;

-(IBAction)handleCloseButton:(id)sender;
-(IBAction)updateVideoQuality:(UISegmentedControl *)sender;

@end

基本上，我想访问viewController中使用setVideoQual函数设置的质量。我使用UISegmentedControl设置了质量。

在viewController.m中

#import "ViewController2.h"

@implementation ViewController2
@synthesize delegate;
-(IBAction)updateVideoQuality:(UISegmentedControl *)sender
{
    NSLog(@"change video quality: %ld", (long)sender.selectedSegmentIndex);


}
-(IBAction)handleCloseButton:(id)sender
{
    [self.delegate setVideoQual:_videoQuality.selectedSegmentIndex];
    [self.navigationController popViewControllerAnimated:YES];

}
@end

在viewController.h中的

我有一个名为VIDEOQUALITY的属性，我想将其设置为从viewController2导入的质量：

viewController.h

#import <UIKit/UIKit.h>
#import "ViewController2.h"


@interface ViewController : UIViewController
{
 ...
NSInteger VIDEOQUALITY;
}

...

@property (nonatomic,assign) NSInteger VIDEOQUALITY;


@end

然后在viewController.m中我有：

@implementation ViewController
@synthesize VIDEOQUALITY;


#pragma mark - UI Actions

- (IBAction)actionStart:(id)sender;
{
    ...
    NSLog(@"NEW VIDEO QUALITY: %d", VIDEOQUALITY);
    ...

}
-(void)setVideoQual:(NSInteger)quality
{
    NSLog(@"SETTING VIDEO QUALITY %ld",quality);
    VIDEOQUALITY=quality;
   }


-(void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    ViewController2 *ViewController2 = [segue destinationViewController];
    ViewController2.delegate = self;
}
@end

我无法弄清楚为什么当我调用actionStart时，VIDEOQUALITY的值永远不会设置为调用setvideoQual函数时设置的值？

Answer 1

为什么要将NSInteger* VIDEOQUALITY;声明为指针？您好像不需要这样，因为NSInteger是原始类型，并且被定义为无符号int NSUInteger（例如）。我想如果你把你的声明改为

{
   NSInteger VIDEOQUALITY;
}
...

@property (nonatomic,assign) NSInteger VIDEOQUALITY;

和实施到

-(void)setVideoQual:(NSInteger)quality
{
    NSLog(@"SETTING VIDEO QUALITY %ld",quality);
    VIDEOQUALITY=quality;
}

你会得到理想的行为。

ios - 无法访问其他视图控制器的数据

1 个答案: