拖动分隔符来调整 UIViews 的大小

Question

实现一个界面的最佳方式是什么，该界面由由一条线分隔的 UIView 组成，并且该线可以调整视图的大小？

以最简单的形式，它可能如下所示：

----------------
|              |  
| View A       |
|              |
|--------------|  < line which can be moved up and down, resizing the views
|              |  
| View B       |   
|              |  
---------------- 

它可以有更多的浏览量。

我的第一个想法是使用Touches 之类的东西使该行成为可拖动的 UIView，它会根据其位置调整视图的大小，但我确信必须有一个更优雅的解决方案。

Answer 1

首先，定义一个手势，检测你是否从边框开始，如果手势改变，则移动所述边框：

#import <UIKit/UIGestureRecognizerSubclass.h>

- (void)viewDidLoad
{
    [super viewDidLoad];

    // I use long press gesture recognizer so it's recognized immediately

    UILongPressGestureRecognizer *gesture = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
    gesture.minimumPressDuration = 0.0;
    gesture.allowableMovement = CGFLOAT_MAX;
    gesture.delegate = self;
    [self.containerView addGestureRecognizer:gesture];
}

- (void)handlePan:(UILongPressGestureRecognizer *)gesture
{
    static NSArray *matches;
    static CGPoint firstLocation;

    if (gesture.state == UIGestureRecognizerStateBegan)
    {
        firstLocation = [gesture locationInView:gesture.view];
        matches = [BorderBeingDragged findBordersBeingDraggedForView:gesture.view fromLocation:firstLocation];
        if (!matches)
        {
            gesture.state = UIGestureRecognizerStateFailed;
            return;
        }
    }
    else if (gesture.state == UIGestureRecognizerStateChanged)
    {
        CGPoint location    = [gesture locationInView:gesture.view];
        CGPoint translation = CGPointMake(location.x - firstLocation.x, location.y - firstLocation.y);
        [BorderBeingDragged dragBorders:matches translation:translation];
    }
}

// if your subviews are scrollviews, you might need to tell the gesture recognizer
// to allow simultaneous gestures

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return TRUE;
}

其次，定义一个BordersBeingDragged类，用于检测边界和改变边界：

typedef enum NSInteger {
    kBorderTypeNone   = 0,
    kBorderTypeLeft   = 1 << 0,
    kBorderTypeRight  = 1 << 1,
    kBorderTypeTop    = 1 << 2,
    kBorderTypeBottom = 1 << 3
} BorderType;

@interface BorderBeingDragged : NSObject

@property (nonatomic, weak) UIView *view;
@property (nonatomic) BorderType borderTypes;
@property (nonatomic) CGRect originalFrame;

@end

static CGFloat const kTolerance = 15.0;

@implementation BorderBeingDragged

+ (NSArray *)findBordersBeingDraggedForView:(UIView *)view fromLocation:(CGPoint)point
{
    NSMutableArray *matches = nil;

    for (UIView *subview in view.subviews)
    {
        BorderType types = kBorderTypeNone;
        CGRect frame = subview.frame;

        // test top and bottom borders

        if (point.x >= (frame.origin.x - kTolerance) &&
            point.x <= (frame.origin.x + frame.size.width + kTolerance))
        {
            if (point.y >= (frame.origin.y - kTolerance) && point.y <= (frame.origin.y + kTolerance))
                types |= kBorderTypeTop;
            else if (point.y >= (frame.origin.y + frame.size.height - kTolerance) && point.y <= (frame.origin.y + frame.size.height + kTolerance))
                types |= kBorderTypeBottom;
        }

        // test left and right borders

        if (point.y >= (frame.origin.y - kTolerance) &&
            point.y <= (frame.origin.y + frame.size.height + kTolerance))
        {
            if (point.x >= (frame.origin.x - kTolerance) && point.x <= (frame.origin.x + kTolerance))
                types |= kBorderTypeLeft;
            else if (point.x >= (frame.origin.x + frame.size.width - kTolerance) && point.x <= (frame.origin.x + frame.size.width + kTolerance))
                types |= kBorderTypeRight;
        }

        // if we found any borders, add it to our array of matches

        if (types != kBorderTypeNone)
        {
            if (!matches)
                matches = [NSMutableArray array];

            BorderBeingDragged *object = [[BorderBeingDragged alloc] init];
            object.borderTypes   = types;
            object.view          = subview;
            object.originalFrame = frame;

            [matches addObject:object];
        }
    }

    return matches;
}

+ (void)dragBorders:(NSArray *)matches translation:(CGPoint)translation
{
    for (BorderBeingDragged *object in matches)
    {
        CGRect newFrame = object.originalFrame;

        if (object.borderTypes & kBorderTypeLeft)
        {
            newFrame.origin.x   += translation.x;
            newFrame.size.width -= translation.x;
        }
        else if (object.borderTypes & kBorderTypeRight)
        {
            newFrame.size.width += translation.x;
        }

        if (object.borderTypes & kBorderTypeTop)
        {
            newFrame.origin.y    += translation.y;
            newFrame.size.height -= translation.y;
        }
        else if (object.borderTypes & kBorderTypeBottom)
        {
            newFrame.size.height += translation.y;
        }

        object.view.frame = newFrame;
    }
}

@end

Answer 2

您确实需要使 line-view 可拖动，但它不需要很复杂。

1. 将viewA 和viewB 放入containerView
2. 将平移手势识别器添加到为单点触摸配置的containerView，并将其代理设置为您的控制器。
3. 从UIGestureRecognizerDelegate 协议实现gestureRecognizerShouldBegin:，并且仅在触摸线视图附近时才允许它开始。
4. 在手势处理程序中获取containerView 中的触摸位置，并为viewA 和viewB 设置线视图位置和帧

差不多了。

Answer 3

我建议其他行为： 1.在线按住2秒 2. 出现一些你要拖动的imageView

Answer 4

最简单的方法是在视图中添加手势识别器并根据平移调整它们的大小。