NSTimer 当我展示另一个视图控制器时不会停止

Question

我有一个viewController1设置了一个计时器。
当计时器倒计时到 0 时，我将呈现 viewController2。
计时器也继续运行，尽管我调用计时器函数invalidate
然后我标记当前视图控制器代码，它似乎正确停止。

//ViewController2 *vc = [[ViewController2 alloc] init];
//[self presentViewController:vc animated:false completion:nil];

代码有什么问题？

#import "ViewController.h"
#import <WebKit/WebKit.h>
#import "ViewController2.h"
@interface ViewController ()<WKScriptMessageHandler, WKNavigationDelegate,WKUIDelegate>
@property (nonatomic,strong) WKWebView* webView;
@property (nonatomic, strong) WKWebViewConfiguration * webConfig;
@property (nonatomic, strong) NSTimer *timer;
@property (nonatomic) int count;
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
self.webView = [[WKWebView alloc] initWithFrame:self.view.frame configuration:[self createWKWebApp]];
[self.view addSubview: self.webView];
[self.webView.configuration.preferences setValue:@YES forKey:@"allowFileAccessFromFileURLs"];
self.webView.scrollView.bounces = NO;
[self.webView setContentMode:UIViewContentModeScaleAspectFit];
self.webView.navigationDelegate = self;
self.webView.UIDelegate = self;
NSURL *url = [NSURL URLWithString:@"https://www.google.com.tw"];
NSURLRequest *request = [NSURLRequest requestWithURL:url];
[self.webView loadRequest:request];
self.count = 5;
self.timer = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(timerFired) userInfo:nil repeats:YES];
}
-(void)timerFired {
NSLog(@"===) self.count : %d", self.count);
if (self.count == 0) {
ViewController2 *vc = [[ViewController2 alloc] init];
[self presentViewController:vc animated:false completion:^{
[self.timer invalidate];
self.timer = nil;
}];
} else {
self.count -= 1;
}
}

- (WKWebViewConfiguration *)createWKWebApp {
WKWebViewConfiguration *config = [[WKWebViewConfiguration alloc] init];
WKUserContentController *userContent = [[WKUserContentController alloc] init];
config.userContentController = userContent;
return config;
}
- (void)userContentController:(WKUserContentController*)userContentController didReceiveScriptMessage:(WKScriptMessage*)message {

}
@end

Answer 1

在呈现视图控制器之前，请停止计时器

[self.timer invalidate];
self.timer = nil;
ViewController2 *vc = [[ViewController2 alloc] init];
[self presentViewController:vc animated:false completion:nil];

Answer 2

使 viewWillDisappear 委托方法中的计时器失效，并在视图再次出现时再次跳动。