书上例程,提示Tread 1:Program received signal:"SIGABRT"难道是链接没有链接好?

部分代码
/*eventreporterViewController.m*/
/*eventreporterViewController.m*/
-(void) touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    [self.nextResponder manageTouches:touches];
}-(void) touchesENDed:(NSSet *)touches withEvent:(UIEvent *)event{
    [self.nextResponder manageTouches:touches];
}-(void) touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{
    [self.nextResponder manageTouches:touches];
}-(void) manageTouches:(NSSet *)touches{
    for(UITouch *touch in touches){
        if(touch.phase == UITouchPhaseBegan){
            CGPoint touchPos = [touch locationInView:self.view];
            startField.center = touchPos;
            startField.text = [NSString stringWithFormat:@"Begin: %3.0f,%3.0f",touchPos.x,touchPos.y];           
            
        }
        else if (touch.phase == UITouchPhaseMoved){
            bottonLabel.text = @"Touch is Moving~";            
        }
        else if (touch.phase == UITouchPhaseEnded){
            if(touch.tapCount > 1){
                bottonLabel.text = [NSString stringWithFormat:@"Taps: %2i",touch.tapCount];
            }
            else {
                bottonLabel.text = [NSString string];                
            }
            CGPoint touchPos = [touch locationInView:self.view];
            endField.center = touchPos;
            endField.text = [NSString stringWithFormat:@"End:%3.0f,%3.0f",touchPos.x,touchPos.y];
        }
        
    }  
    
}有几个警告这是链接