Question

I have an UIScrollview and which contains UIView as a subview like,

here i can able to drag the UIView inside the ScrollView, when the uiview goes to at END RIGHT or END LEFT the uiview disappears inside scrollview, after that i has to scroll the scrollview then i can able to see the uiview, here i need to SCROLL THE SCROLLVIEW when uiview comes at the rightside or left side, for that i used this code but not working.

[myscrollview scrollRectToVisible:myview.frame animated:YES];

Answer 1

Here I have used on UIButton (as it is already used in one of my application I dont need to write whole code again)

[cropRectangleButton addTarget:self action:@selector(imageMoved:withEvent:) forControlEvents:UIControlEventTouchDragInside];

The cropRectangleButton is one UIButton and the imageMoved:withEvent: method is as below

- (IBAction) imageMoved:(id)sender withEvent:(UIEvent *)event
{
    CGPoint point = [[[event allTouches] anyObject] locationInView:self.view];

    CGPoint prev = lastTouchDownPoint;
    lastTouchDownPoint = point;
    CGFloat diffX = point.x - prev.x;
    CGFloat diffY = point.y - prev.y;

    UIControl *button = sender;
    CGRect newFrame = button.frame;
    newFrame.origin.x += diffX;
    newFrame.origin.y += diffY;
    scrollView.contentSize = CGSizeMake(2*scrollView.frame.size.width, scrollView.frame.size.height);
    [scrollView scrollRectToVisible:newFrame animated:YES];
    button.frame = newFrame;
}

Here I change my contentSize of scrollView as it is very narrow to test that the scrollView is scrolling or not you don’t need that line of code.

And when I drag the button left the scrollView is also automatically scrolled to the button frame to show the whole button try to implement this using UIView and if not possible just put one transparant UIButton on your view fully covered the view and you it to do the drag 🙂