Some ingenious tricks for iOS development 2

Some ingenious tricks for iOS development 2

Is it possible to use only one pan gesture to replace all directions of UISwipegesture?

 - ( void )pan:(UIPanGestureRecognizer *)sender
 {
 typedef NS_ENUM(NSUInteger, UIPanGestureRecognizerDirection) {
    UIPanGestureRecognizerDirectionUndefined,
    UIPanGestureRecognizerDirectionUp,
    UIPanGestureRecognizerDirectionDown,
    UIPanGestureRecognizerDirectionLeft,
    UIPanGestureRecognizerDirectionRight
 };
 static UIPanGestureRecognizerDirection direction = UIPanGestureRecognizerDirectionUndefined;
 switch (sender.state) {
 case UIGestureRecognizerStateBegan: {
 if (direction == UIPanGestureRecognizerDirectionUndefined) {
            CGPoint velocity = [sender velocityInView:recognizer.view];
            BOOL isVerticalGesture = fabs(velocity.y) > fabs(velocity.x);
 if (isVerticalGesture) {
 if (velocity.y > 0 ) {
                    direction = UIPanGestureRecognizerDirectionDown;
 } else {
                    direction = UIPanGestureRecognizerDirectionUp;
 }
 }
 else {
 if (velocity.x > 0 ) {
                    direction = UIPanGestureRecognizerDirectionRight;
 } else {
                    direction = UIPanGestureRecognizerDirectionLeft;
 }
 }
 }
 break ;
 }
 case UIGestureRecognizerStateChanged: {
 switch (direction) {
 case UIPanGestureRecognizerDirectionUp: {
                [self handleUpwardsGesture:sender];
 break ;
 }
 case UIPanGestureRecognizerDirectionDown: {
                [self handleDownwardsGesture:sender];
 break ;
 }
 case UIPanGestureRecognizerDirectionLeft: {
                [self handleLeftGesture:sender];
 break ;
 }
 case UIPanGestureRecognizerDirectionRight: {
                [self handleRightGesture:sender];
 break ;
 }
 default : {
 break ;
 }
 }
 break ;
 }
 case UIGestureRecognizerStateEnded: {
        direction = UIPanGestureRecognizerDirectionUndefined;
 break ;
 }
 default :
 break ;
 }
 }

How can I keep the image from being deformed when stretching it?

1. UIImage *image = [[UIImage imageNamed:@"xxx"] stretchableImageWithLeftCapWidth:10 topCapHeight:10];
   (Someone just reminded me that this has been deprecated. The current method is called resizableImageWithCapInsets).

Why is it so slow when playing GIF? Is there a better library?

FlipBoard's is perfect for you. https://github.com/Flipboard/FLAnimatedImage

How to add pull-to-refresh in one sentence?

https://github.com/samvermette/SVPullToRefresh

 [tableView addPullToRefreshWithActionHandler:^{
 // prepend data to dataSource, insert cells at top of table view
 // call [tableView.pullToRefreshView stopAnimating] when done
 } position:SVPullToRefreshPositionBottom];

How to change the color of the small check mark in the cell of tableview to another color?

 _mTableView.tintColor = [UIColor redColor];

Originally my statusbar was lightcontent, but using UIImagePickerController caused the style of my statusbar to turn black. What should I do?

 - ( void )navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
 {
    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent];
 }

How can I make my navigationbar transparent instead of blurry?

 [self.navigationBar setBackgroundImage:[UIImage new ]
                         forBarMetrics:UIBarMetricsDefault];
 self.navigationBar.shadowImage = [UIImage new ];
 self.navigationBar.translucent = YES;

How to change the color and position of uitextfield placeholder?

Inherit uitextfield and override this method

 - ( void ) drawPlaceholderInRect:(CGRect)rect {
    [[UIColor blueColor] setFill];
    [self.placeholder drawInRect:rect withFont:self.font lineBreakMode:UILineBreakModeTailTruncation alignment:self.textAlignment];
 }

Why do you know so many weird tricks?

Go to stackoverflow and post questions, young man!