多点触控导致方法触发两次

Question

我正在开发一款将 ipad 屏幕分为下半部分和上半部分的小游戏。每个玩家都有自己的部分可以玩（一个手指游戏）。我必须在视图上启用多点触控，因为当两个玩家同时点击屏幕时，只有一个玩家的方法会被执行或根本不执行。

但是，当 2 个玩家执行完全相同的操作时，这会导致方法触发两次的奇怪行为。这就是它现在的工作方式： 它检查玩家是否触摸了视图中的对象。如果有，就会触发一个方法。如果玩家没有触摸对象而是视图本身，则会触发另一个方法。它检查视图是在上半部分还是下半部分被触摸，以区分玩家一或玩家二的触摸。

我一直在考虑一个解决方案，但我不确定什么是解决这个问题的好方法。也许我应该为每个玩家分开视图（透明），以便我可以更轻松地区分触摸？这是我的 touchesBegan 方法。

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

    NSMutableSet *touchedCirclesPlayerOne = [NSMutableSet set];
    NSMutableSet *touchedCirclesPlayerTwo = [NSMutableSet set];

    for (UITouch *touch in touches) {
        CGPoint touchLocation = [touch locationInView:self.view];
        for (Circle *circle in playerOneCircles) {
            if ([circle.layer.presentationLayer hitTest:touchLocation]) {
                [touchedCirclesPlayerOne addObject:circle];

            } 
        }

    for (UITouch *touch in touches) {
        CGPoint touchLocation = [touch locationInView:self.view];
        for (Circle *circle in playerTwoCircles) {
            if ([circle.layer.presentationLayer hitTest:touchLocation]) {
                [touchedCirclesPlayerTwo addObject:circle];

                } 
            }
    }

    if (touchedCirclesPlayerOne.count) {

        NSLog(@"test");

        for (Circle *circle in touchedCirclesPlayerOne) {

            [circle playerTap:nil];

        }

    } else if (touchedCirclesPlayerTwo.count) {

        NSLog(@"test2");

        for (Circle *circle in touchedCirclesPlayerTwo) {

            [circle SecondPlayerTap:nil];

        }


    } else {

        for (UITouch *touch in touches) {
            CGPoint touchLocation = [touch locationInView:self.view];

            if (CGRectContainsPoint(CGRectMake(0, self.view.frame.size.height/2, self.view.frame.size.width, self.view.frame.size.height/2), touchLocation)) {

            NSLog(@"wrong player 1");
            [[NSNotificationCenter defaultCenter] postNotificationName:@"wrong player 1" object:self];

            }  else {

                NSLog(@"wrong player 2");
                [[NSNotificationCenter defaultCenter] postNotificationName:@"wrong player 2" object:self];
            }

        }


    }

}

}

这里有一个小示意图。这一切都有效，除非两个玩家做同样的事情。它会为每个玩家触发两次相同的动作。

Answer 1

该代码看起来很熟悉:-)。然而，你所拥有的东西做了很多额外的工作。此外，如果有两次点击，它将始终是玩家 1 的点击，而不是玩家 2 的点击。

您真的想强制每个玩家区域点击一次吗？ 请注意，此代码不会阻止这种情况。您可以在前一次触球后开始另一次触球，这不会在集合中。但是，您可以通过查看对象来查看所有当前触摸，而不管它们的状态如何。查询 allTouches，它将为您提供屏幕上的所有当前触摸。

考虑以下更改...

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
    // Since this rect object is always needed, you probably want to
    // make it once, and keep it as private variables.  If your area is
    // not really divided completely in half, you will want two separate
    // rects, each defining the area for each player.
    CGRect player1Area = CGRectMake(0, self.view.frame.size.height/2, self.view.frame.size.width, self.view.frame.size.height/2);

    // For performance sake, we will loop through the touches a single time
    // and process each tap in that loop.  Use these flags to later determine
    // what to do if the player tapped some place other than on a circle.
    BOOL player1Tapped = NO;
    BOOL player2Tapped = NO;
    BOOL player1TappedCircle = NO;
    BOOL player2TappedCircle = NO;

    for (UITouch *touch in touches) {
        CGPoint touchLocation = [touch locationInView:self.view];
        if (CGRectContainsPoint(player1Area, touchLocation)) {
            // This touch is in player 1's area
            // Small additional code to restrict player to a single tap.
            player1Tapped = YES;
            for (Circle *circle in playerOneCircles) {
                // I guess you are using a CAShapeLayer, and looking at the
                // position during animation?
                if ([circle.layer.presentationLayer hitTest:touchLocation]) {
                    player1TappedCircle = YES;
                    [circle playerTap:nil];
                }
            }
        } else {
            // This touch is not for player 1, so must be for player 2...
            player2Tapped = YES;
            for (Circle *circle in playerTwoCircles) {
                if ([circle.layer.presentationLayer hitTest:touchLocation]) {
                    player2TappedCircle = YES;
                    [circle secondPlayerTap:nil];
                }
            }
        }
    }

    // All touches have now been handled.  We can do stuff based on whether any player
    // has tapped any area, or circles, or whatever.
    if (player1Tapped && !player1TappedCircle) {
        // Player 1 tapped, but did not tap on a circle.
    }
    if (player2Tapped && !player2TappedCircle) {
        // Player 2 tapped, but did not tap on a circle.
    }    
}

Answer 2

我会把它分成两个视图。然后，我会为每个视图附加一个手势识别器。

UITapGestureRecognizer *tapRecog1 = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap1:)] autorelease]; 

[self.view1 addGestureRecognizer:self.tapRecog1]; 

UITapGestureRecognizer *tapRecog2 = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTap2:)] autorelease]; 

[self.view2 addGestureRecognizer:self.tapRecog2];

然后，我将实现动作方法。

- (void)handleTap1:(UITapGestureRecognizer *)tap;
{
    CGPoint point = [tap locationInView:self.view1];

    // do stuff
}

- (void)handleTap2:(UITapGestureRecognizer *)tap;
{
    CGPoint point = [tap locationInView:self.view2];

    // do stuff
}