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POMaking use of velocityInView with UIPanGestureRecognizer
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  1. POMaking use of velocityInView with UIPanGestureRecognizer
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    copied!<p>I have a custom slider-type object, that I wish to make more usable. Currently I use <code>UIPanGestureRecognizer</code> and <code>translationInView</code> to make it work. It works pretty well but I'd like some sort of velocity in there to make it feel a bit more useful. I've tried a few things but cant quite figure out how to properly implement velocity <code>changedLevel</code> equation.</p> <pre><code>- (void)panDetected:(UIPanGestureRecognizer *)gesture { CGPoint swipeLocation = [gesture locationInView:self.tableView]; NSIndexPath *indexPath = [self.tableView indexPathForRowAtPoint:swipeLocation]; LevelCounterTableCell *swipedCell = (LevelCounterTableCell *)[self.tableView cellForRowAtIndexPath:indexPath]; if([gesture state] == UIGestureRecognizerStateBegan) { NSString *originalLevelString = swipedCell.levelNumber.text; originalLevel = [originalLevelString intValue]; // int originalLevel } if ([gesture state] == UIGestureRecognizerStateChanged) { CGFloat xTranslation = [gesture translationInView:[[gesture view] superview]].x; CGFloat xVelocity = [gesture velocityInView: [[gesture view] superview]].x; // Pan threshold is currently set to 8.0. // 8.0 is a decent level for slow panning // for fast panning 2.0 is more reasonable changedLevel = ceilf((xTranslation / panThreshold) + originalLevel); // int changedLevel // Raw velocity seems to go from around 3 (slow) // to over 200 (fast) NSLog(@"raw velocity = %f", xVelocity); if (changedLevel &gt;= 15 &amp;&amp; changedLevel &lt;= 100) { swipedCell.levelNumber.text = [NSString stringWithFormat:@"%i", changedLevel]; swipedCell.meter.frame = [self updateMeter: changedLevel]; } } if ([gesture state] == UIGestureRecognizerStateEnded || [gesture state] == UIGestureRecognizerStateCancelled) { if (changedLevel &gt;= 15 &amp;&amp; changedLevel &lt;= 100) { //... Save the values... } } } </code></pre> <p>Any help would be greatly appreciated. Thank you.</p>
 

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