弹出到view2时如何恢复计时器 [英] how to resume timer when poping to view2
问题描述
我的应用有 3 次浏览
my application has 3 views
在视图 1 中只有一个按钮(播放级别 1)推送到 veiw2 并更新视图 2 中的标题标签
in view1 only one button (play level 1) that pushes to veiw2 and updates titlelabel in view2
当 view2 加载并出现计时器开始倒计时并更新 view2 本身中的另一个标签时，view2 也有按钮暂停计时器并推送到 view3
when view2 loads and appears a timer starts to count down and update another label in view2 itself, also view2 has button that pauses the timer and pushes to view3
在 view3 中只有一个按钮可以弹回 view2 并恢复计时器
in view3 only one button that pop back to view2 and resumes thee timer
我的问题是，当我从 view3 弹出到 view2 时，计时器仍然暂停
my problem is that when i pop from view3 to view2 the timer is still paused
有什么帮助吗?
谢谢&亲切的问候.
Thanks & kind regards.
view1.h
#import <UIKit/UIKit.h>
@interface view1 : UIViewController
-(IBAction)nextpage;
@end
view1.m
#import "view1.h"
#import "view2.h"
@interface view1 ()
@end
@implementation view1
-(IBAction)nextpage{
view2 *obj = [[view2 alloc] init];
[self.navigationController pushViewController:obj animated:YES];
[obj.leveltitle setText:@"Level"];
obj.time=10;
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
[self.navigationController setNavigationBarHidden:YES];
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
@end
view2.h
#import <UIKit/UIKit.h>
@interface view2 : UIViewController
{
int time;
NSTimer *timer;
BOOL paused;
}
@property (nonatomic, retain) NSTimer *timer;
@property (readwrite, nonatomic) int time;
@property (nonatomic) BOOL paused;
@property (readwrite, retain) IBOutlet UILabel *leveltitle;
@property (nonatomic, readwrite) IBOutlet UILabel *label;
-(IBAction)back;
-(IBAction)pause;
@end
view2.m
#import "view2.h"
#import "view3.h"
@interface view2 ()
@end
@implementation view2
@synthesize leveltitle, label;
@synthesize time, timer;
@synthesize paused;
-(void)countDown2
{
if (paused == NO && time>0)
{
time = time -1 ;
view3 *obj = [[view3 alloc] init];
obj.sss = time;
if (time == 0)
{
[timer invalidate];
}
[label setText:[NSString stringWithFormat:@"%i",time]];
}
}
-(IBAction)back{
[self.navigationController popViewControllerAnimated:YES];
}
-(IBAction)pause{
view3 *obj = [[view3 alloc] init];
[self.navigationController pushViewController:obj animated:YES];
paused = YES;
}
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
// Custom initialization
}
return self;
}
- (void)viewDidLoad
{
paused = NO;
timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(countDown2) userInfo:nil repeats:YES];
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation: (UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
@end
view3.h
#import <UIKit/UIKit.h>
@interface view3 : UIViewController
{
int sss;
}
@property (nonatomic) int sss;
-(IBAction)back;
@end
view3.m
#import "view3.h"
#import "view2.h"
@interface view3 ()
@end
@implementation view3
@synthesize sss;
-(IBAction)back{
view2 *obj = [[view2 alloc] init];
obj.paused=NO;
obj.timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(cont) userInfo:nil repeats:YES];
//[obj.timer fire];
[self.navigationController popViewControllerAnimated:YES];
}
-(void)cont{
view2 *obj = [[view2 alloc] init];
obj.time = sss;
if (obj.paused == NO && time>0)
{
obj.time = obj.time -1 ;
if (obj.time == 0)
{
[obj.timer invalidate];
}
[obj.label setText:[NSString stringWithFormat:@"%i",obj.time]];
}
}
- (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 from its nib.
}
- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
@end
推荐答案
这是因为在view3的back方法中，你创建了一个新的瞬间view2 命名 obj 并设置 paused=NO.但是当你弹回来时，那个 obj 和 view2 是不一样的.你需要做的是使用委托方法模式，这样view3就会在view2中有一个回调方法，将paused设置为<代码>否.
It is because in view3's back method, you created a new instant of view2 name obj and set paused=NO. But that obj was not the same instant of view2 when you pop back. What you need to do is to use a delegate method pattern, so that view3 will have a callback method in view2 to set the paused to NO.
有关委托方法模式的示例，请查看以下示例 SO.
For an example of delegate method pattern, check out an example from this SO.
示例回调代码:
对您的代码进行这些添加/更改:
Make these addition/changes to your code:
在view2.h中:
#import "view3.h"
@interface view2 : UIViewController <view3Delegate>
在 view2.m 中:
In view2.m:
-(IBAction)pause{
view3 *obj = [[view3 alloc] init];
obj.delegate = self; //adding this line
[self.navigationController pushViewController:obj animated:YES];
paused = YES;
}
-(void)setPausedValue:(BOOL)value //this is the new method callback from view3 to set paused value
{
paused = value;
}
在view3.h中:
#import <UIKit/UIKit.h>
@protocol view3Delegate <NSObject>
-(void) setPausedValue:(BOOL)value;
@end
@interface view3 : UIViewController
{
int sss;
}
@property (assign) id <view3Delegate> delegate;
@property (nonatomic) int sss;
-(IBAction)back;
@end
在 view3.m 中:
In view3.m:
@implementation view3
@synthesize delegate;
-(IBAction)back{
// view2 *obj = [[view2 alloc] init];
// obj.paused=NO;
[self.delegate setPausedValue:NO]; //make callback and set value
obj.timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(cont) userInfo:nil repeats:YES];
//[obj.timer fire];
[self.navigationController popViewControllerAnimated:YES];
}
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