主线程EXC_BAD_ACCESS KERN_INVALID_ADDRESS (来自iOS 8.x的NSTimer )

Question

从破碎机上摔下来的。

Crashed: com.apple.main-thread

0  libobjc.A.dylib                0x197e37bdc objc_msgSend + 28
1  Foundation                     0x1881192c8 -[NSCFTimer initWithFireDate:interval:target:selector:userInfo:repeats:] + 140
2  Foundation                     0x188123d3c +[NSTimer(NSTimer) scheduledTimerWithTimeInterval:target:selector:userInfo:repeats:] + 140
3  RV PetSafety                   0x1000fd2a0 -[HomeViewController UIApplicationDidBecomeActive:] (HomeViewController.m:179)
4  CoreFoundation                 0x1872dc1e0 __CFNOTIFICATIONCENTER_IS_CALLING_OUT_TO_AN_OBSERVER__ + 20
5  CoreFoundation                 0x18721b370 _CFXNotificationPost + 2060
6  Foundation                     0x188116cc0 -[NSNotificationCenter postNotificationName:object:userInfo:] + 72
7  UIKit                          0x18bb664c0 -[UIApplication _stopDeactivatingForReason:] + 464
8  UIKit                          0x18bd77818 -[UIApplication _handleNonLaunchSpecificActions:forScene:withTransitionContext:] + 2664
9  FrontBoardServices             0x18f56d640 __31-[FBSSerialQueue performAsync:]_block_invoke + 28
10 CoreFoundation                 0x1872ee124 __CFRUNLOOP_IS_CALLING_OUT_TO_A_BLOCK__ + 20
11 CoreFoundation                 0x1872ed22c __CFRunLoopDoBlocks + 312
12 CoreFoundation                 0x1872eb850 __CFRunLoopRun + 1756
13 CoreFoundation                 0x1872191f4 CFRunLoopRunSpecific + 396
14 GraphicsServices               0x1903835a4 GSEventRunModal + 168
15 UIKit                          0x18bb4a784 UIApplicationMain + 1488
16 RV PetSafety                   0x1001161e8 main (main.m:14)
17 libdyld.dylib                  0x198492a08 start + 4

我的代码：

- (void)UIApplicationDidBecomeActive:(NSNotification *)notification {
    if([updateTimer isValid]) {
        [updateTimer invalidate];
    }
    updateTimer = [NSTimer scheduledTimerWithTimeInterval:refreshInterval
                                                   target:self
                                                 selector:@selector(refreshData)
                                                 userInfo:nil
                                                  repeats:YES];
}

每当我的应用程序变得活跃时，我就想更新我的NSTimer时间。我需要调用API一段时间。我在这个方法上出了点问题。在上述选择器方法中，refreshData具有API调用。在NSNotificationCenter上初始化viewWillAppear

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(UIApplicationDidBecomeActive:)
                                             name:UIApplicationDidBecomeActiveNotification object:nil];

在这一行上的碰撞学标题HomeViewController.m line 179 -[HomeViewController UIApplicationDidBecomeActive:]

updateTimer = [NSTimer scheduledTimerWithTimeInterval:refreshInterval
                                                   target:self
                                                 selector:@selector(refreshData)
                                                 userInfo:nil
                                                  repeats:YES];

我在这个项目中没有看到任何[[NSNotificationCenter defaultCenter] removeObserver:self name:UIApplicationDidBecomeActiveNotification object:nil];。刚才我补充说，但是，我想确认是否是由于多个addObserver或在NSTimer初始化中发生了崩溃？

更新16/08/2017:

得到这个错误的时间

iOS版本: 8.4.1 (12H 321) 型号: iPhone 5c (Model A1456，A1532)

更新17/08/2017:

第一次坠机发生在三个多月前，第二次发生在两周以上。我无法在Xcode-organizer崩溃选项卡中获得崩溃详细信息。我只在Crashlytics，没有在Xcode-organizer上看到过一些其他的崩溃。我无法理解Crashlytics崩溃的细节与Xcode-organizer相比

Answer 1

您不能将观察者代码放在viewWillAppear中，因为代码会调用残废时间：

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(UIApplicationDidBecomeActive:)
                                             name:UIApplicationDidBecomeActiveNotification
                                           object:nil];