Question

@interface ClassWithTimer : NSObject {

}
-(void) startTimer;
-(void) stopTimer;
@end

@implementation ClassWithTimer

NSTimer *up;

-(void) startTimer{
    up = [NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(doSomething) userInfo:nil repeats:YES];

-(void) stopTimer{
    [up invalidate];
}

- (void) doSomething{}
@end

然后我做

- (IBAction)startTimers:(id)sender {
    timer1 = [[ClassWithTimer alloc] initWithName:@"time1"];
    timer2 = [[ClassWithTimer alloc] initWithName:@"time2"];

    [timer1 startTimer];
    [timer2 startTimer];    

    [timer1 stopTimer];
    [timer2 stopTimer];
}

当我停止计时器时，我看到timer1与timer2相同，而invalidate方法在[timer2 stopTimer]中抛出异常，因为此时此对象无效。

我知道这是iOS政策，但我找不到相关的文档。

Answer 1

移动

  NSTimer *up;

进入接口块内的.h文件。

Answer 2

NSTimer需要是一个iVar，你只需要在类中自由声明，允许两个类共享相同的计时器。您还需要释放上一个计时器，然后在startTimer中保留新计时器。

@interface ClassWithTimer : NSObject {
    NSTimer *up; //Declare iVar(instance variables) here
}
-(void) startTimer;
-(void) stopTimer;
@end

@implementation ClassWithTimer

-(void) startTimer{
    [up invalidate];
    [up release];
    up = [[NSTimer scheduledTimerWithTimeInterval:1 target:self selector:@selector(doSomething) userInfo:nil repeats:YES] retain];

-(void) stopTimer{
    [up invalidate]; //Do these same this line
    [up release];    //and this line in your dealloc
    up = nil;
}

- (void) doSomething{}
@end

IOS将相同但不同的对象设置为一个内存地址

2 个答案: