Ios-like Sina Weibo UINavigationController displays the View of the previous controller when sliding to the left.

Ios-like Sina Weibo UINavigationController displays the View of the previous controller when sliding to the left.

The View of the previous controller is displayed when the Sina Weibo UINavigationController slides left.

Implementation principle: when the self. view of UINavigationController is displayed, the current view is saved to an array. When a view is pushed, the previous view is placed behind self. view. When self. view is dragged to the right, the previous view is displayed.

NavigationController. m

# Import "NavigationController. h "@ interface NavigationController ()/** store the full screen of each controller */@ property (nonatomic, strong) NSMutableArray * images; @ property (nonatomic, strong) UIImageView * lastVcView; @ property (nonatomic, strong) UIView * cover; @ end @ implementation NavigationController-(UIImageView *) lastVcView {if (! _ LastVcView) {UIWindow * window = [UIApplication sharedApplication]. keyWindow; UIImageView * lastVcView = [[UIImageView alloc] init]; lastVcView. frame = window. bounds; self. lastVcView = lastVcView;} return _ lastVcView;}-(UIView *) cover {if (! _ Cover) {UIWindow * window = [UIApplication sharedApplication]. keyWindow; UIView * cover = [[UIView alloc] init]; cover. backgroundColor = [UIColor blackColor]; cover. frame = window. bounds; cover. alpha = 0.5; self. cover = cover;} return _ cover;}-(NSMutableArray *) images {if (! _ Images) {self. images = [[NSMutableArray alloc] init];} return _ images;}-(void) viewDidLoad {[super viewDidLoad]; // drag gesture UIPanGestureRecognizer * recognizer = [[UIPanGestureRecognizer alloc] initWithTarget: self action: @ selector (dragging :)]; [self. view addGestureRecognizer: recognizer];}-(void) dragging :( UIPanGestureRecognizer *) recognizer {// if there is only one sub-controller, stop dragging if (self. viewControllers. count <= 1) return; // The distance from CGFloat tx = [recognizer translationInView: self. view]. x; if (tx <0) return; if (recognizer. state = UIGestureRecognizerStateEnded | recognizer. state = UIGestureRecognizerStateCancelled) {// determine whether to restore the pop or CGFloat x = self. view. frame. origin. x; if (x> = self. view. frame. size. width * 0.5) {[UIView animateWithDuration: 0.25 animations: ^ {self. view. transform = CGAffineTransformMakeTranslation (self. view. frame. size. width, 0);} completion: ^ (BOOL finished) {[self popViewControllerAnimated: NO]; [self. lastVcView removeFromSuperview]; [self. cover removeFromSuperview]; self. view. transform = CGAffineTransformIdentity; [self. images removeLastObject];} else {[UIView animateWithDuration: 0.25 animations: ^ {self. view. transform = CGAffineTransformIdentity;}] ;}} else {// move view self. view. transform = CGAffineTransformMakeTranslation (tx, 0); UIWindow * window = [UIApplication sharedApplication]. keyWindow; // Add it to the end of self. lastVcView. image = self. images [self. images. count-2]; [window insertSubview: self. lastVcView atIndex: 0]; [window insertSubview: self. cover aboveSubview: self. lastVcView] ;}}/*** generate */-(void) createScreenShot {uigraphicsbeginimagecontextwitexceptions (self. view. frame. size, YES, 0.0); [self. view. layer renderInContext: UIGraphicsGetCurrentContext ()]; UIImage * image = UIGraphicsGetImageFromCurrentImageContext (); [self. images addObject: image];}-(void) viewDidAppear :( BOOL) animated {[super viewDidAppear: animated]; if (self. images. count> 0) return; [self createScreenShot];}-(void) pushViewController :( UIViewController *) viewController animated :( BOOL) animated {[super pushViewController: viewController animated: animated]; [self createScreenShot];} @ end