我正在尝试从我的应用程序委托(delegate)运行一个方法，该方法将对象保存在其他类中并使计时器无效。我已将其设置为当我的应用程序退出时，它会运行我的类中的方法并保存并停止计时器。
在应用程序委托(delegate)中:
- (void)applicationWillResignActive:(UIApplication *)application {
// Save the mission because they are leaving the app
if ([timeRun hasScore]) {
[timeRun resetWithSave];
}
}
它在“timeRun”类中调用的方法:
- (void)resetWithSave {
// Save
self.counterInt = 150;
self.timer.text = [self timeInSeconds:counterInt];
[start setBackgroundImage:[UIImage imageNamed:@"play.png"] forState:UIControlStateNormal];
self.started = NO;
self.score.text = @"0";
[self saveMission];
if ([countTimer isValid]) {
[countTimer invalidate];
}
[table scrollRectToVisible:CGRectMake(0, 0, 1, 1) animated:NO];
}
但是，我遇到了崩溃:
2010-09-11 19:35:21.503 Score Card[2747:307] -[__NSCFType isValid]: unrecognized selector sent to instance 0x19e190
2010-09-11 19:35:21.594 Score Card[2747:307] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFType isValid]: unrecognized selector sent to instance 0x19e190'
*** Call stack at first throw:
(
0 CoreFoundation 0x30897ed3 __exceptionPreprocess + 114
1 libobjc.A.dylib 0x3002f811 objc_exception_throw + 24
2 CoreFoundation 0x30899683 -[NSObject(NSObject) doesNotRecognizeSelector:] + 102
3 CoreFoundation 0x308411d9 ___forwarding___ + 508
4 CoreFoundation 0x30840f90 _CF_forwarding_prep_0 + 48
5 Score Card 0x00006b3d -[TimeRun resetWithSave] + 272
6 Score Card 0x00002b39 -[Score_CardAppDelegate applicationWillResignActive:] + 80
7 UIKit 0x31ea6879 -[UIApplication _setActivated:] + 212
8 UIKit 0x31eda4ab -[UIApplication _handleApplicationSuspend:eventInfo:] + 238
9 UIKit 0x31eab301 -[UIApplication handleEvent:withNewEvent:] + 2200
10 UIKit 0x31eaa901 -[UIApplication sendEvent:] + 44
11 UIKit 0x31eaa337 _UIApplicationHandleEvent + 5110
12 GraphicsServices 0x31e4504b PurpleEventCallback + 666
13 CoreFoundation 0x3082cce3 __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE1_PERFORM_FUNCTION__ + 26
14 CoreFoundation 0x3082cca7 __CFRunLoopDoSource1 + 166
15 CoreFoundation 0x3081f56d __CFRunLoopRun + 520
16 CoreFoundation 0x3081f277 CFRunLoopRunSpecific + 230
17 CoreFoundation 0x3081f17f CFRunLoopRunInMode + 58
18 GraphicsServices 0x31e445f3 GSEventRunModal + 114
19 GraphicsServices 0x31e4469f GSEventRun + 62
20 UIKit 0x31e51123 -[UIApplication _run] + 402
21 UIKit 0x31e4f12f UIApplicationMain + 670
22 Score Card 0x000029ef main + 70
23 Score Card 0x000029a4 start + 40
)
terminate called after throwing an instance of 'NSException'
Program received signal: “SIGABRT”.
kill
quit
为什么这会让我的应用程序崩溃？
最佳答案
凭直觉，你正在做类似的事情
countTimer = [NSTimer scheduledTimerWithTarget:...];
...
if ([countTimer isValid])
{
[countTimer invalidate];
}
...
if ([countTimer isValid])
{
[countTimer invalidate];
}
已为您将“预定”计时器添加到运行循环中。然后它被运行循环保留。使其无效会将其从运行循环中删除，从而将其释放。如果没有其他东西保留它，它将被释放。当您尝试再次使用它时，它会崩溃。
尝试类似[countTimer invalidate]; countTimer = nil;
或者，您可以保留计时器，但请注意，计时器保留其目标，因此很容易导致保留周期。
关于iPhone:应用程序委托(delegate)中的 NSTimer 无效导致应用程序崩溃，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/3693553/