如何在 ios 9 中关闭 UIView.xib 时在 UIViewController 中重新启动预定的 NSTimer？

Question

我创建了一个计时器，它在 10.0 秒后触发并调用 targetMethod: on self，它是一个指向 NSTimer instance.This 计时器的指针，它应该只在其关联的 viewcontroller 屏幕打开时工作view.I 在加载名为 PhotoView.xib 的 .xib 文件时停止了计时器，因为计时器阻塞了 UI。但是当 PhotoView.xib 从 Viewcontroller 变为 removed/dismissed 时，我不知道如何再次启动计时器。有人能告诉我当 .xib 从父 Viewcontroller 中解雇时如何重新启动计时器（父 Viewcontroller 的）吗？

SampleView.h

#import <UIKit/UIKit.h>

@interface SampleView : UIView

@property(nonatomic,retain)IBOutlet UIView* view;
@property(nonatomic,retain)IBOutlet UIImageView* imageview;
@property(nonatomic,retain)IBOutlet UIButton* dismissButton;

@end

SampleView.m

#import "GroupPhotoView.h"

@implementation SampleView
@synthesize imageview,view,dismissButton;

-(IBAction) dismissView: (id) sender{
    [self removeFromSuperview];
}

@end

SampleViewController.h

#import <UIKit/UIKit.h>

@interface SampleViewController : UIViewController
@property(nonatomic,retain)NSTimer *timer;

@end

SampleViewController.m

#import "SampleViewController.h"

@interface SampleViewController ()
@end

@implementation SampleViewController
@synthesize timer;


- (void)viewDidLoad {
    [super viewDidLoad];
}

-(void)viewDidAppear:(BOOL)animated{

self.timer=[NSTimer scheduledTimerWithTimeInterval:10 target:self  selector:@selector(sampleMethod:) userInfo:nil repeats:YES];
}

-(void)viewWillDisappear:(BOOL)animated{
    //stop the timer when SampleVC is not in the view
    if ([self.timer isValid])
    {
        [self.timer invalidate];
        self.timer=nil;
    }
}

- (IBAction)displayAction:(id)sender
{
    [self loadSampleImage];
}


-(void)loadSampleImage:(UIImage*)aImage{

    if ([self.timer isValid])
    {
        [self.timer invalidate];
        self.timer=nil;
    }

    SampleView *customView =(SampleView *)[[[NSBundle mainBundle]   loadNibNamed:@"PhotoView" owner:self options:nil] objectAtIndex:0];
    customView.backgroundColor = [UIColor colorWithWhite:0 alpha:0.8];
    customView.imageview.image=[UIImage imageNamed:@"cs"];

    [customView setFrame:self.view.frame];
    [self.navigationController.view addSubview:customView];
 }
}

@end

提前致谢。

Answer 1

您可以使用Delegate再次重启NSTimer。委托允许一个对象在事件发生时向另一个对象发送消息。当对象 A 调用对象 B 时，委托用于类似的问题，但是一旦操作完成，A 应该知道 B 已完成任务并采取必要的操作。

创建示例视图：

// Delegate to respond back in SampleView.m
id <SampleView> _delegate; 
// OR in SampleView.h
@property (strong, nonatomic) id _delegate;

在 SampleView.m 中添加操作完成后调用：

-(IBAction) dismissView: (id) sender{
    [self removeFromSuperview];
    [_delegate startTimer];
}

在SampleViewController.m中添加方法启动定时器：

customView.delegate = self;

-(void)startTimer
{
    self.timer=[NSTimer scheduledTimerWithTimeInterval:10 target:self  selector:@selector(sampleMethod:) userInfo:nil repeats:YES];
}

.xib 从 parentViewcontroller 中退出后，它将再次启动计时器。

如何在 ios 9 中关闭 UIView.xib 时在 UIViewController 中重新启动预定的 NSTimer？

How to restart the scheduled NSTimer in UIViewController when UIView.xib is dismissed in ios 9?

objective-c

xib

nstimer

ios9.3