Can a pan gesture be used for moving UIWindows?

Question

Is it possible to move a UIWindow via a pan gesture recognizer? I've been having issues understanding how the gestures works and have managed to get it working for views but not windows.

Answer 1

Yes, you can.

UIWindow is subclass of UIView and you can add PanGesture normally. To move window, change frame of UIApplication.sharedApplication.delegate.window, it will work fine.

Create a new project and replace AppDelegate.m file with my code below. You can move window.

#import "AppDelegate.h"

@interface AppDelegate ()

@property (nonatomic, strong) UIPanGestureRecognizer* panGesture;
@property (nonatomic, assign) CGPoint lastPoint;

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  // Override point for customization after application launch.

  self.panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePanGesture:)];
  [self.window addGestureRecognizer:_panGesture];
  _needUpdate = YES;

  return YES;
}

- (void)handlePanGesture:(UIPanGestureRecognizer *)panGesture {
  CGPoint point = [panGesture locationInView:self.window];
  CGPoint center = self.window.center;

  if (CGPointEqualToPoint(_lastPoint, CGPointZero)) {
    _lastPoint = point;
  }

  center.x += point.x - _lastPoint.x;
  center.y += point.y - _lastPoint.y;
  self.window.frame = [UIScreen mainScreen].bounds;
  self.window.center = center;

  if (panGesture.state == UIGestureRecognizerStateEnded) {
    _lastPoint = CGPointZero;
  }
}


@end