使用CFDictionary跟踪UITouches

Question

我正在寻找一些示例代码来跟踪一个CFDictionary的UITouches。不幸的是，苹果文档并没有一个完整的例子。

http://developer.apple.com/library/IOs/#documentation/EventHandling/Conceptual/EventHandlingiPhoneOS/MultitouchEvents/MultitouchEvents.html#//apple_ref/doc/uid/TP40009541-CH3-SW7

我目前使用的是NSMutable数组，但我想存储完整的UITouch对象，因此也要获得时间戳。

NSMutableArray *touchArray_val;


-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    touchArray_val = [[NSMutableArray alloc] init];             
}

-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{ 

     for(UITouch *t in touches){
         CGPoint currentPoint = [t locationInView:self];
         [touchArray_val addObject:[NSValue valueWithCGPoint: currentPoint]];    
     }

}

-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{        
    NSLog(@"%i",[touchArray count]);

    for(NSValue *val in touchArray_val){        
        NSLog(@"%@",val);      
    }
}

Answer 1

在触摸的整个生命周期内，UITouch的指针不会改变。您可以从指针创建NSValue。

 // NSMutableDictionary * touchLookup; set up somewhere else...
 NSValue * key = [NSValue valueWithPointer:touch];
 [touchLookup setObject:touch forKey:key];