使用拖动手势在父视图中移动UIView

Question

我想在父视图中移动一个视图，我使用UIPanGestureRecognizer来移动视图。我正在使用以下代码。

-(void)move:(UIPanGestureRecognizer *)recognizer {
    CGPoint touchLocation = [recognizer locationInView:self.customeView];

    self.view.center = touchLocation;
}

我想使用 locationInView 来移动视图，而不是使用 translationInView。有人能帮我了解如何在父视图中使用 locationInView 来移动视图吗？

- Uttam

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问题是将可拖动视图的坐标从子视图转换为父视图吗？还是根本无法移动它？ - Kyle Clegg

我在使用translationInView时遇到了问题，所以我现在使用locationInView来替代。 - Uttam

Answer 1

你使用 UIPanGestureRecognizer 是正确的。你可能缺少了开始和结束手势状态处理。这是一个完整的解决方案，我刚刚在一个样例项目中编写了一个 panView，它是视图控制器根视图的子类（Swift）。

class ViewController: UIViewController {

    @IBOutlet weak var panView: UIView!

    // records the view's center for use as an offset while dragging
    var viewCenter: CGPoint!

    override func viewDidLoad() {
        super.viewDidLoad()
        panView.addGestureRecognizer(UIPanGestureRecognizer(target: self, action: #selector(self.dragView)))
    }

    func dragView(gesture: UIPanGestureRecognizer) {
        let target = gesture.view!

        switch gesture.state {
        case .began, .ended:
            viewCenter = target.center
        case .changed:
            let translation = gesture.translation(in: self.view)
            target.center = CGPoint(x: viewCenter!.x + translation.x, y: viewCenter!.y + translation.y)
        default: break
        }
    }

}

- Kyle Clegg

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谢谢您的回复，@Kyle Clegg，但我想在UIPanGestureRecognizer方法中使用locationInView。但是您在上面的代码中使用了translationInView。 - Uttam

Answer 2

你可以尝试这个。

@interface ViewController ()
@property (weak, nonatomic) IBOutlet UIView *panView;

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    //self.panView = self.panView -> self.view . self.panView is direct child of self.view

    UIPanGestureRecognizer *panRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(move:)];
    [self.panView addGestureRecognizer:panRecognizer];


    // Do any additional setup after loading the view, typically from a nib.
}

-(void)move:(UIPanGestureRecognizer *)recognizer {
    CGPoint centerPoint = [recognizer locationInView:self.view];
    self.panView.center = centerPoint;
}
}

- jignesh Vadadoriya

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