好的，我正在帮助将 Android 游戏转换为 iOS。该游戏基于 2048，但使用字母而非数字。我有很多工作，但仍在学习 Objective C/iOS 怪癖。到目前为止，我的瓷砖/网格工作正常，运动正常等，但我需要一些帮助。目标是允许用户长按一个图 block 来选择它，然后将他们的手指滑动到相邻的图 block 以开始拼写单词。我已经实现了长按部分，但我对如何让它长按然后滑动有点不知所措。最重要的是，我已经有了允许用户移动磁贴的滑动。在此处搜索时，我看到了有关子类化的建议，因此我认为我需要对 UISwipeGestureRecognizer 方法进行子类化。我已经安装了同步手势识别器，但不确定从这里到哪里去。

所以，这有几个问题。

1. 执行此操作的最佳方法是什么？实现每个 UISwipeGestureRecognizer 的子类？

2. 我当前的滑动检测会干扰吗？ (现在滑动本身会沿滑动方向移动图 block )

3. 我想我需要做一个(如果长按)然后激活子类滑动方法？

4. 回答上述问题的任何例子都会有很大帮助。我不是要你为我做这件事，但至少要给我指出一个大方向。谢谢!

下面的代码。

//  Grid.m
#import "Grid.h"
#import "Tile.h"

- (void)didLoadFromCCB {
    // listen for swipes to the left
    UISwipeGestureRecognizer * swipeLeft= [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeLeft)];
    swipeLeft.direction = UISwipeGestureRecognizerDirectionLeft;
    [[[CCDirector sharedDirector] view] addGestureRecognizer:swipeLeft];

    // listen for swipes to the right
    UISwipeGestureRecognizer * swipeRight= [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeRight)];
    swipeRight.direction = UISwipeGestureRecognizerDirectionRight;
    [[[CCDirector sharedDirector] view] addGestureRecognizer:swipeRight];

    // listen for swipes up
    UISwipeGestureRecognizer * swipeUp= [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeUp)];
    swipeUp.direction = UISwipeGestureRecognizerDirectionUp;
    [[[CCDirector sharedDirector] view] addGestureRecognizer:swipeUp];

    // listen for swipes down
    UISwipeGestureRecognizer * swipeDown= [[UISwipeGestureRecognizer alloc]initWithTarget:self action:@selector(swipeDown)];
    swipeDown.direction = UISwipeGestureRecognizerDirectionDown;
    [[[CCDirector sharedDirector] view] addGestureRecognizer:swipeDown];

    // listen for long press
    UILongPressGestureRecognizer *longpress = [[UILongPressGestureRecognizer alloc]initWithTarget:self action:@selector(onLongPress:)];
    [longpress setMinimumPressDuration:0.5];
    [[[CCDirector sharedDirector] view] addGestureRecognizer:longpress];
}

- (void)swipeLeft {
    [self move:ccp(-1, 0)];
}
- (void)swipeRight {
    [self move:ccp(1, 0)];
}
- (void)swipeDown {
    [self move:ccp(0, -1)];
}
- (void)swipeUp {
    [self move:ccp(0, 1)];
}

// detect longpress, convert to NodeSpace and check if touch location is within tile boundingbox. If yes, set background white, text black.
- (void)onLongPress:(UILongPressGestureRecognizer *) recognizer {
    CGPoint touchPoint = [[CCDirector sharedDirector] convertToGL:[recognizer locationInView:[recognizer view]]];
    touchPoint = [self convertToNodeSpace:touchPoint];

    if (recognizer.state == UIGestureRecognizerStateBegan) {
        for (Tile *tile in self.children) {
            if([tile isKindOfClass:[Tile class]]) {

                CGRect tileBoundingBox = tile.boundingBox;
                if (CGRectContainsPoint(tileBoundingBox, touchPoint)) {

                    tile.backgroundNode.color = [CCColor whiteColor];
                    tile.valueLabel.color = [CCColor blackColor];
                    [self spellWord:tile.value];
                    [_word setString:[_word lowercaseString]];
                    CCLOG(@"%@", _word);
                }
            }
        }
    }

    if (recognizer.state == UIGestureRecognizerStateChanged) {

    }

    if (recognizer.state == UIGestureRecognizerStateEnded) {
        for (Tile *tile in self.children) {
            if([tile isKindOfClass:[Tile class]]) {

                CGRect tileBoundingBox = tile.boundingBox;
                if (CGRectContainsPoint(tileBoundingBox, touchPoint)) {
                    tile.backgroundNode.color = [tile getColor:tile.value];
                    tile.valueLabel.color = [self getContrastColor:r green:g blue:b];

                }
            }
        }
    }
}

// allow for simultaneous gestures
- (BOOL)gestureRecognizer:(UIGestureRecognizer *) recognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
    return YES;
}

最佳答案

回答您的问题:

1. 我并不觉得这是一种需要对 UILongPressGestureRecognizer 进行子类化的编码情况。话虽如此，子类化通常是清理 View Controller 代码的好方法，这样您就不会在 View Controller 类中有血腥的手势识别器代码。但这里(据我了解)没有任何要求。您通常会深入研究手势识别器的子类化，您需要一些特殊的自定义行为(例如，如果某些复杂的标准失败，则让手势失败)。不过，在我走那条路之前，我会先看看您是否可以使用标准手势实现所需的用户体验。

2. 我能看到滑动手势相互干扰的唯一原因是您已指定 shouldRecognizeSimultaneouslyWithGestureRecognizer 应返回 YES。这用于需要同时运行多个识别器的情况，这在这里似乎没有必要(而且只是问题的根源)。

   我不清楚您是真的想要一个单独的滑动手势还是只想要一个手势(“长按并拖动”)。但是，如果您需要单独的滑动手势，您通常会通过指定 requireGestureRecognizerToFail 来指定手势识别器的相对优先级(例如，让滑动需要长按失败才能识别滑动)。但是，如果您真的只有一种手势(“长按并拖动”)，那么只需要一种手势识别器。

3. 好像没必要。如果您想在长按被识别后检测移动，您可以将“长按后移动”代码放入 中 UIGestureRecognizedStateChanged 的 if 语句中onLongPress，在识别出长按之后，但在用户抬起手指之前发生。 UILongPressGestureRecognizer 是一个连续的手势识别器，在初始识别手势后，它将随着用户手指的移动继续获取更新。

我知道你没有要求代码，但如果你想要一个滑动手势，以及一个长按手势，本质上就是拿起它并拖动它的想法，你可以做如下的事情.请注意，我使滑动手势需要长按才能失败，因此如果用户长按，则优先，否则它会滑动。但您可能根本不需要滑动手势，所以如果您不需要它，只需将其完全删除即可:

#import <UIKit/UIGestureRecognizerSubclass.h>

- (void)viewDidLoad {
    [super viewDidLoad];

    UILongPressGestureRecognizer *longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handleLongPress:)];
    [self.view addGestureRecognizer:longPress];

    // if you needed a second gesture, a swipe, completely distinct from the long press and drag
    // gesture, you could add it like so:
    //
    // UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(handleSwipe:)];
    // [swipe requireGestureRecognizerToFail:longPress];
    // // do additional swipe configuration
    // [self.view addGestureRecognizer:swipe];
}

- (void)handleSwipe:(UISwipeGestureRecognizer *)gesture
{
    // do your separate swipe stuff here
}

- (void)handleLongPress:(UILongPressGestureRecognizer *)gesture
{
    static UIView *tileToMove;
    static CGPoint startCenter;
    static CGPoint startLocation;

    CGPoint location = [gesture locationInView:self.view];

    switch (gesture.state) {
        case UIGestureRecognizerStateBegan:
        {
            // find the tile

            tileToMove = [self findTileToMove:location];
            if (tileToMove) {
                // if found, capture state ...

                startCenter = tileToMove.center;
                startLocation = location;

                // ... and animate "pick up tile", so the user gets positive feedback
                // that the drag/swipe portion of the gesture is starting.

                [UIView animateWithDuration:0.25 animations:^{
                    tileToMove.transform = CGAffineTransformMakeScale(1.2, 1.2);
                }];
            } else {
                gesture.state = UIGestureRecognizerStateFailed;
            }
            break;
        }
        case UIGestureRecognizerStateChanged:
        {
            // move the tile as the user's finger moves

            CGPoint translate = CGPointMake(location.x - startLocation.x, location.y - startLocation.y);

            // note, if you want to constrain the translation to be, for example, on the
            // x-axis alone, you could do something like:
            //
            // CGPoint translate = CGPointMake(location.x - startLocation.x, 0);

            tileToMove.center = CGPointMake(startCenter.x + translate.x, startCenter.y + translate.y);
            break;
        }
        case UIGestureRecognizerStateEnded:
        {
            // animate "drop the tile"

            [UIView animateWithDuration:0.25 animations:^{
                tileToMove.transform = CGAffineTransformIdentity;

                // if you want the tile to "snap" to some location having let it go,
                // set the `center` or `frame` here.
            }];

            // clear our variables, just in case

            tileToMove = nil;
            startCenter = CGPointZero;
            startLocation = CGPointZero;
            break;
        }
        default:
            break;
    }
}

- (UIView *)findTileToMove:(CGPoint)location
{
    for (UIView *tile in self.tiles) {
        if (CGRectContainsPoint(tile.frame, location)) {
            return tile;
        }
    }

    return nil;
}

这可能不是您正在寻找的 UI，但它说明了:

1. 如何拥有两个手势，其中一个需要另一个手势失败，以便在手势之间建立优先级(如果您想要两个不同的手势，这显然只是一个问题，而您可能不需要)；

2. 没有 shouldRecognizeSimultaneouslyWithGestureRecognizer 方法，因为我不想同时识别它们。请注意，仅当您确实需要两个手势时才需要这样做，您可能需要也可能不需要；和

3. 如何让长按不仅能识别初始长按，还能识别后续的滑动/拖动 Action 。

关于ios - 长按后滑动，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/25045991/