Objective-C switch语句的奇怪行为

Question

I have a game that uses a global integer position to navigate around the options menu. When the back button is pressed for every screen, it calls a function, [self options] , to reload the original "options" screen. I have a feeling that this is something extremely silly I messed up.

Now, the code that calls the function that determines whether or not the back button is this:

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

With touchIsInNode: being my own custom method for handling taps returning a BOOL value ( YES if it was).

Naming the buttons for the back buttons for each screen backa , backb , backc , etc. is a viable workaround, but it still calls the code in each switch case regardless of the value of position .

Here's what I have going on in my switch statement:

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;
            }
        }
}

My options method looks like this:

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

Then, for each submenu in the options menu, they look like this (using the "store" one as a model):

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]];

The result of this code is, each case is executed, even after position 's value has changed to 1 to signify going back to the options menu. Also, didBeginTouches is oddly called 5 times although I only "tapped" the screen once in the simulator. Here are the more relevant parts of what I have for a log:

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

Why does every case run, even the default case? It seems like only position == 4 should run case 4 and something like position == 500 would run the default case. If it helps, there are 5 sub-menus in the options menu.

Answer 1

您需要在每个case块的末尾添加一个break语句。