Objective-C switch语句的奇怪行为

Question

我有一个使用全局整数position在选项菜单中导航的游戏。 当为每个屏幕按下返回按钮时，它将调用函数[self options] ，以重新加载原始的“ options”屏幕。 我感觉这是我弄得很傻的东西。

现在，调用确定后退按钮是否为以下函数的代码：

if ([self touchIsInNode:[self childNodeWithName:@"back"] touchPoint:touchPoint]) {
                    // stuff should happen here
                }

使用touchIsInNode:是我自己的自定义方法，用于处理返回BOOL值的水龙头（如果YES则为YES ）。

为每个屏幕backa ， backb ， backc等命名后退按钮是一种可行的解决方法，但是无论position的值如何，它仍会在每种开关情况下调用代码。

这是我在switch语句中所做的事情：

switch (position) {
            // case 0 thru 3 are unrelated to the question... 0 is for the main menu, 1 is for the original logic for the "options" screen, 2 is for the end of the game, and 3 is to skip to the end of the intro screen.
            case 4:
            {
                NSLog(@"position: %i", position);
                if ([self touchIsInNode:[self childNodeWithName:@"backa"] touchPoint:touchPoint]) {
                    NSLog(@"store back button was pressed and [self options] is being called...");
                    [self options];
                }
                // store UI
            }
            case 5:
            {
                NSLog(@"position: %i", position);
                if ([self touchIsInNode:[self childNodeWithName:@"backb"] touchPoint:touchPoint]) {
                    NSLog(@"stats back button was pressed and [self options] is being called...");
                    [self options];
                }
                // stats UI
            }
            case 6:
            {
                NSLog(@"position: %i", position);
                if ([self touchIsInNode:[self childNodeWithName:@"backc"] touchPoint:touchPoint]) {
                    NSLog(@"about back button was pressed and [self options] is being called...");
                    [self options];
                }
                // about UI
            }
            case 7:
            {
                NSLog(@"position: %i", position);
                if ([self touchIsInNode:[self childNodeWithName:@"backe"] touchPoint:touchPoint]) {
                    NSLog(@"dev options back button was pressed and [self options] is being called...");
                    [self options];
                }
                // dev options UI
            }
            case 8:
            {
                NSLog(@"position: %i", position);
                if ([self touchIsInNode:[self childNodeWithName:@"backd"] touchPoint:touchPoint]) {
                    NSLog(@"purchased options back button was pressed and [self options] is being pressed...");
                    [self options];
                }
                // purchased options UI
            }
            default:
            {
                NSLog(@"INVALID POSITION: %i", position);
                break;
            }
        }
}

我的options方法如下所示：

for (SKNode* node in [self children]) {
    // fade out and remove each node if it is not "optionsButton"
    if (![node.name isEqual:@"optionsButton"]) {
        [node runAction:[SKAction fadeAlphaTo:0 duration:1] completion:^{
            [node removeFromParent];
        }];
    } else {
        // if it is "optionsButton", perform an animation.
        [node runAction:[SKAction scaleTo:1.5 duration:1]];
        [node runAction:[SKAction moveTo:CGPointMake(self.size.width / 2, self.size.height - ((node.frame.size.height * (4.0 / 3.0)) / node.yScale)) duration:1] completion:^{
            // afterwards, call a method that logs each node's name.
            [self logEveryNode];
        }];
    }
}
position = 1;
NSLog(@"position: %i", position);

// processing labels

// add in each child

NSLog(@"options called, with %i nodes in [self children]", [self children].count);

// fade in all of the labels

然后，对于选项菜单中的每个子菜单，它们看起来都像这样（使用“存储”作为模型）：

position = 4;
for (SKNode* node in [self children]) {
    if ([node.name isEqual:@"optionsButton"]) {
        [node runAction:[SKAction scaleTo:(2.0 / 3.0) duration:1]];
        [node runAction:[SKAction moveTo:CGPointMake(self.size.width / 2, self.size.height - (node.frame.size.height * (1.0 / 3.0))) duration:1]];
    } else if ([node.name isEqual:@"store"]) {
        [node runAction:[SKAction scaleTo:1.5 duration:1]];
        [node runAction:[SKAction moveTo:CGPointMake(self.size.width / 2, self.size.height - node.frame.size.height * 3) duration:1]];
    } else {
        [node runAction:[SKAction fadeAlphaTo:0 duration:1] completion:^{
            [node removeFromParent];
        }];
    }
}

// draw UI for the store and move the back button accordingly

SKLabelNode *back = [SKLabelNode labelNodeWithFontNamed:@"Cochin"];
back.alpha = 0;
back.fontColor = [UIColor blackColor];
back.text = @"back";
back.name = @"backa";
back.fontSize = 44;
back.position = CGPointMake(self.size.width / 2, self.size.height * 0.5);

[self addChild:back];

[back runAction:[SKAction fadeAlphaTo:1 duration:1]];

即使position的值已更改为1表示返回到options菜单，该代码的结果也会在每种情况下执行。 同样， didBeginTouches被奇怪地调用了5次，尽管我在模拟器中只“轻按”了一次屏幕。 以下是与日志相关的部分：

2015-05-23 01:10:40.581 game[25258:1981445] position: 4
2015-05-23 01:10:40.581 game[25258:1981445] store back button was pressed and [self options] is being called...
2015-05-23 01:10:40.582 game[25258:1981445] position: 1
2015-05-23 01:10:40.588 game[25258:1981445] options called, with 10 nodes in [self children]
2015-05-23 01:10:40.588 game[25258:1981445] position: 1
2015-05-23 01:10:40.588 game[25258:1981445] position: 1
2015-05-23 01:10:40.588 game[25258:1981445] position: 1
2015-05-23 01:10:40.589 game[25258:1981445] position: 1
2015-05-23 01:10:40.589 game[25258:1981445] INVALID POSITION: 1

为什么每个case运行，甚至是default案例？ 似乎只有position == 4才能运行case 4 ，而position == 500类的东西可以运行default情况。 如果有帮助，则选项菜单中有5个子菜单。

Answer 1

您需要在每个case块的末尾添加一个break语句。