Ok, i've read a few posts on this one (ex. UIImageView Gestures (Zoom, Rotate) Question) but I can't seem to fix my problem.
I have the following setup: an SKScene, an SKNode _backgroundLayer and 9 SKSpriteNodes that are tiles that make up the background and are attached to the _backgroundLayer.
Since these 9 tiles make a 3x3 square and they are quite large, I need to be able to zoom in and look at other SKSpriteNodes that will be on top of these 9 background images.
There are two problems:
1) When I pinch to zoom in or zoom out it seems like it is zooming in/out from location (0,0) of the _backgroundLayer and not from the touch location.
2) I have added some bounds so that the user can not scroll out of the 9 background images. In general it works. However, if I zoom in then move towards the top of the 9 background images and then zoom out the bounding conditions go berserk and the user can see the black space outside the background images. I need a way to limit the amount of zooming out that the user can do depending on where he's at.
Any ideas? Thanks!
I include my code below:
#import "LevelSelectScene.h"
#import "TurtleWorldSubScene.h"
#interface LevelSelectScene ()
#property (nonatomic, strong) SKNode *selectedNode;
#end
#implementation LevelSelectScene
{
SKNode *_backgroundLayer;
}
-(id)initWithSize:(CGSize)size {
if (self = [super initWithSize:size]) {
/* Setup your scene here */
_backgroundLayer = [SKNode node];
_backgroundLayer.name = #"backgroundLayer";
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
[_backgroundLayer setScale:0.76];
} else if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone && IS_WIDESCREEN) {
} else {
[_backgroundLayer setScale:0.36];
}
[self addChild:_backgroundLayer];
SKTexture *backgroundTexture = [SKTexture textureWithImageNamed:#"levelSelect"];
int textureID = 0;
for (int i = 0; i<3; i++) {
for (int j = 0; j<3; j++) {
SKSpriteNode *background = [SKSpriteNode spriteNodeWithTexture:backgroundTexture];
background.anchorPoint = CGPointZero;
background.position = CGPointMake((background.size.width)*i, (background.size.height)*j);
background.zPosition = 0;
background.name = [NSString stringWithFormat:#"background%d", textureID];
textureID++;
[_backgroundLayer addChild:background];
}
}
[TurtleWorldSubScene displayTurtleWorld:self];
}
return self;
}
- (void)didMoveToView:(SKView *)view {
UIPanGestureRecognizer *panGestureRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePanFrom:)];
[[self view] addGestureRecognizer:panGestureRecognizer];
//UITapGestureRecognizer * tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTap:)];
// [self.view addGestureRecognizer:tapRecognizer];
UIPinchGestureRecognizer *pinchGestureRecognizer = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:#selector(handlePinch:)];
[[self view] addGestureRecognizer:pinchGestureRecognizer];
}
- (void)handlePanFrom:(UIPanGestureRecognizer *)recognizer {
if (recognizer.state == UIGestureRecognizerStateBegan) {
CGPoint touchLocation = [recognizer locationInView:recognizer.view];
touchLocation = [self convertPointFromView:touchLocation];
SKNode *node = [self nodeAtPoint:touchLocation];
_selectedNode = node;
} else if (recognizer.state == UIGestureRecognizerStateChanged) {
CGPoint translation = [recognizer translationInView:recognizer.view];
translation = CGPointMake(translation.x, -translation.y);
CGPoint initialPosition = CGPointAdd(_backgroundLayer.position, translation);
_backgroundLayer.position = [self boundLayerPos:initialPosition];
[recognizer setTranslation:CGPointZero inView:recognizer.view];
} else if (recognizer.state == UIGestureRecognizerStateEnded) {
float scrollDuration = 0.2;
CGPoint velocity = [recognizer velocityInView:recognizer.view];
CGPoint pos = [_backgroundLayer position];
CGPoint p = CGPointMultiplyScalar(velocity, scrollDuration);
CGPoint newPos = CGPointMake(pos.x + p.x, pos.y - p.y);
newPos = [self boundLayerPos:newPos];
[_backgroundLayer removeAllActions];
SKAction *moveTo = [SKAction moveTo:newPos duration:scrollDuration];
[moveTo setTimingMode:SKActionTimingEaseOut];
[_backgroundLayer runAction:moveTo];
}
}
- (void)handlePinch:(UIPinchGestureRecognizer *) recognizer
{
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad) {
if(_backgroundLayer.xScale*recognizer.scale < 0.76) {
//SKSpriteNode *backgroundTile = (SKSpriteNode *)[_backgroundLayer childNodeWithName:#"background0"];
[_backgroundLayer setScale:0.76];
} else if(_backgroundLayer.xScale*recognizer.scale > 2) {
[_backgroundLayer setScale:2.0];
} else {
[_backgroundLayer runAction:[SKAction scaleBy:recognizer.scale duration:0]];
}
} else if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone && IS_WIDESCREEN) {
} else {
if(_backgroundLayer.xScale*recognizer.scale < 0.36) {
[_backgroundLayer setScale:0.36];
} else if(_backgroundLayer.xScale*recognizer.scale > 2) {
[_backgroundLayer setScale:2.0];
} else {
[_backgroundLayer runAction:[SKAction scaleBy:recognizer.scale duration:0]];
}
}
recognizer.scale = 1;
}
- (CGPoint)boundLayerPos:(CGPoint)newPos {
SKSpriteNode *backgroundTile = (SKSpriteNode *)[_backgroundLayer childNodeWithName:#"background0"];
CGPoint retval = newPos;
retval.x = MIN(retval.x, 0);
retval.x = MAX(retval.x, -(backgroundTile.size.width*_backgroundLayer.xScale*3)+self.size.width);
retval.y = MIN(retval.y, 0);
retval.y = MAX(retval.y, -(backgroundTile.size.height*_backgroundLayer.xScale*3)+self.size.height);
return retval;
}
I'm working on an app with 9 views on screen, and I want the users to connect the views in a way they want, and record their sequence as password.
But I don't know which gesture recognizer I should use.
Should I use CMUnistrokeGestureRecognizer or combination of several swipe gesture or anything else?
Thanks.
You could use a UIPanGestureRecognizer, something like:
CGFloat const kMargin = 10;
- (void)viewDidLoad
{
[super viewDidLoad];
// create a container view that all of our subviews for which we want to detect touches are:
CGFloat containerWidth = fmin(self.view.bounds.size.width, self.view.bounds.size.height) - kMargin * 2.0;
UIView *container = [[UIView alloc] initWithFrame:CGRectMake(kMargin, kMargin, containerWidth, containerWidth)];
container.backgroundColor = [UIColor darkGrayColor];
[self.view addSubview:container];
// now create all of the subviews, specifying a tag for each; and
CGFloat cellWidth = (containerWidth - (4.0 * kMargin)) / 3.0;
for (NSInteger column = 0; column < 3; column++)
{
for (NSInteger row = 0; row < 3; row++)
{
UIView *cell = [[UIView alloc] initWithFrame:CGRectMake(kMargin + column * (cellWidth + kMargin),
kMargin + row * (cellWidth + kMargin),
cellWidth, cellWidth)];
cell.tag = row * 3 + column;
cell.backgroundColor = [UIColor lightGrayColor];
[container addSubview:cell];
}
}
// finally, create the gesture recognizer
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self
action:#selector(handlePan:)];
[container addGestureRecognizer:pan];
}
- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static NSMutableArray *gesturedSubviews;
// if we're starting a gesture, initialize our list of subviews that we've gone over
if (gesture.state == UIGestureRecognizerStateBegan)
{
gesturedSubviews = [NSMutableArray array];
}
// now figure out whether:
// (a) are we over a subview; and
// (b) is this a different subview than we last were over
CGPoint location = [gesture locationInView:gesture.view];
for (UIView *subview in gesture.view.subviews)
{
if (CGRectContainsPoint(subview.frame, location))
{
if (subview != [gesturedSubviews lastObject])
{
[gesturedSubviews addObject:subview];
// an example of the sort of graphical flourish to give the
// some visual cue that their going over the subview in question
// was recognized
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionAutoreverse
animations:^{
subview.alpha = 0.5;
}
completion:^(BOOL finished){
subview.alpha = 1.0;
}];
}
}
}
// finally, when done, let's just log the subviews
// you would do whatever you would want here
if (gesture.state == UIGestureRecognizerStateEnded)
{
NSLog(#"We went over:");
for (UIView *subview in gesturedSubviews)
{
NSLog(#" %d", subview.tag);
}
// you might as well clean up your static variable when you're done
gesturedSubviews = nil;
}
}
Obviously, you would create your subviews any way you want, and keep track of them any way you want, but the idea is to have subviews with unique tag numbers, and the gesture recognizer would just see which order you go over them in a single gesture.
Even if I didn't capture precisely what you want, it at least shows you how you can use a pan gesture recognizer to track the movement of your finger from one subview to another.
Update:
If you wanted to draw a path on the screen as the user is signing in, you could create a CAShapeLayer with a UIBezierPath. I'll demonstrate that below, but as a caveat, I feel compelled to point out that this might not be a great security feature: Usually with password entry, you'll show the user enough so that they can confirm that they're doing what they want, but not enough so that someone can glance look over their shoulder and see what the whole password was. When entering a text password, usually iOS momentarily shows you the last key you hit, but quickly turns that into an asterisk so that, at no point, can you see the whole password. Hence my initial suggestion.
But if you really have your heart set on showing the user the path as they draw it, you could use something like the following. First, this requires Quartz 2D. Thus add the QuartzCore.framework to your project (see Linking to a Library or Framework). Second, import the QuartCore headers:
#import <QuartzCore/QuartzCore.h>
Third, replace the pan handler with something like:
- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static NSMutableArray *gesturedSubviews;
static UIBezierPath *path = nil;
static CAShapeLayer *shapeLayer = nil;
// if we're starting a gesture, initialize our list of subviews that we've gone over
if (gesture.state == UIGestureRecognizerStateBegan)
{
gesturedSubviews = [NSMutableArray array];
}
// now figure out whether:
// (a) are we over a subview; and
// (b) is this a different subview than we last were over
CGPoint location = [gesture locationInView:gesture.view];
for (UIView *subview in gesture.view.subviews)
{
if (!path)
{
// if the path hasn't be started, initialize it and the shape layer
path = [UIBezierPath bezierPath];
[path moveToPoint:location];
shapeLayer = [[CAShapeLayer alloc] init];
shapeLayer.strokeColor = [UIColor redColor].CGColor;
shapeLayer.fillColor = [UIColor clearColor].CGColor;
shapeLayer.lineWidth = 2.0;
[gesture.view.layer addSublayer:shapeLayer];
}
else
{
// otherwise add this point to the layer's path
[path addLineToPoint:location];
shapeLayer.path = path.CGPath;
}
if (CGRectContainsPoint(subview.frame, location))
{
if (subview != [gesturedSubviews lastObject])
{
[gesturedSubviews addObject:subview];
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionAutoreverse
animations:^{
subview.alpha = 0.5;
}
completion:^(BOOL finished){
subview.alpha = 1.0;
}];
}
}
}
// finally, when done, let's just log the subviews
// you would do whatever you would want here
if (gesture.state == UIGestureRecognizerStateEnded)
{
// assuming the tags are numbers between 0 and 9 (inclusive), we can build the password here
NSMutableString *password = [NSMutableString string];
for (UIView *subview in gesturedSubviews)
[password appendFormat:#"%c", subview.tag + 48];
NSLog(#"Password = %#", password);
// clean up our array of gesturedSubviews
gesturedSubviews = nil;
// clean up the drawing of the path on the screen the user drew
[shapeLayer removeFromSuperlayer];
shapeLayer = nil;
path = nil;
}
}
That yields a path that the user draws as the gesture proceeds:
Rather than showing the path the user draws with each and every movement of the user's finger, maybe you just draw the lines between the center of the subviews, such as:
- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static NSMutableArray *gesturedSubviews;
static UIBezierPath *path = nil;
static CAShapeLayer *shapeLayer = nil;
// if we're starting a gesture, initialize our list of subviews that we've gone over
if (gesture.state == UIGestureRecognizerStateBegan)
{
gesturedSubviews = [NSMutableArray array];
}
// now figure out whether:
// (a) are we over a subview; and
// (b) is this a different subview than we last were over
CGPoint location = [gesture locationInView:gesture.view];
for (UIView *subview in gesture.view.subviews)
{
if (CGRectContainsPoint(subview.frame, location))
{
if (subview != [gesturedSubviews lastObject])
{
[gesturedSubviews addObject:subview];
if (!path)
{
// if the path hasn't be started, initialize it and the shape layer
path = [UIBezierPath bezierPath];
[path moveToPoint:subview.center];
shapeLayer = [[CAShapeLayer alloc] init];
shapeLayer.strokeColor = [UIColor redColor].CGColor;
shapeLayer.fillColor = [UIColor clearColor].CGColor;
shapeLayer.lineWidth = 2.0;
[gesture.view.layer addSublayer:shapeLayer];
}
else
{
// otherwise add this point to the layer's path
[path addLineToPoint:subview.center];
shapeLayer.path = path.CGPath;
}
[UIView animateWithDuration:0.25
delay:0.0
options:UIViewAnimationOptionAutoreverse
animations:^{
subview.alpha = 0.5;
}
completion:^(BOOL finished){
subview.alpha = 1.0;
}];
}
}
}
// finally, when done, let's just log the subviews
// you would do whatever you would want here
if (gesture.state == UIGestureRecognizerStateEnded)
{
// assuming the tags are numbers between 0 and 9 (inclusive), we can build the password here
NSMutableString *password = [NSMutableString string];
for (UIView *subview in gesturedSubviews)
[password appendFormat:#"%c", subview.tag + 48];
NSLog(#"Password = %#", password);
// clean up our array of gesturedSubviews
gesturedSubviews = nil;
// clean up the drawing of the path on the screen the user drew
[shapeLayer removeFromSuperlayer];
shapeLayer = nil;
path = nil;
}
}
That yields something like:
You have all sorts of options, but hopefully you now have the building blocks so you can design your own solution.
Forgive me Rob, pure Plagiarism here :) Needed the same code in swift 3.0 :) so I translated this great little example you wrote into swift 3.0.
ViewController.swift
import UIKit
class ViewController: UIViewController {
static let kMargin:CGFloat = 10.0;
override func viewDidLoad()
{
super.viewDidLoad()
// create a container view that all of our subviews for which we want to detect touches are:
let containerWidth = fmin(self.view.bounds.size.width, self.view.bounds.size.height) - ViewController.kMargin * 2.0
let container = UIView(frame: CGRect(x: ViewController.kMargin, y: ViewController.kMargin, width: containerWidth, height: containerWidth))
container.backgroundColor = UIColor.darkGray
view.addSubview(container)
// now create all of the subviews, specifying a tag for each; and
let cellWidth = (containerWidth - (4.0 * ViewController.kMargin)) / 3.0
for column in 0 ..< 3 {
for row in 0 ..< 3 {
let cell = UIView(frame: CGRect(x: ViewController.kMargin + CGFloat(column) * (cellWidth + ViewController.kMargin), y: ViewController.kMargin + CGFloat(row) * (cellWidth + ViewController.kMargin), width: cellWidth, height: cellWidth))
cell.tag = row * 3 + column;
container.addSubview(cell)
}
}
// finally, create the gesture recognizer
let pan = UIPanGestureRecognizer(target: self, action: #selector(handlePan))
container.addGestureRecognizer(pan)
}
func handlePan(gesture: UIPanGestureRecognizer)
{
var gesturedSubviews : [UIView] = []
// if we're starting a gesture, initialize our list of subviews that we've gone over
if (gesture.state == .began)
{
gesturedSubviews.removeAll()
}
let location = gesture.location(in: gesture.view)
for subview in (gesture.view?.subviews)! {
if (subview.frame.contains(location)) {
if (subview != gesturedSubviews.last) {
gesturedSubviews.append(subview)
subview.backgroundColor = UIColor.blue
}
}
// finally, when done, let's just log the subviews
// you would do whatever you would want here
if (gesture.state != .recognized)
{
print("We went over:");
for subview in gesturedSubviews {
print(" %d", (subview as AnyObject).tag);
}
// you might as well clean up your static variable when you're done
}
}
}
}
Update: Almost that is; I tried to translate the update too, but my translation missed something and didn't work, so I searched around SO and crafted a similar if slightly different final solution.
import UIKit
import QuartzCore
class ViewController: UIViewController {
static let kMargin:CGFloat = 10.0;
override func viewDidLoad()
{
super.viewDidLoad()
// create a container view that all of our subviews for which we want to detect touches are:
let containerWidth = fmin(self.view.bounds.size.width, self.view.bounds.size.height) - ViewController.kMargin * 2.0
let container = UIView(frame: CGRect(x: ViewController.kMargin, y: ViewController.kMargin, width: containerWidth, height: containerWidth))
container.backgroundColor = UIColor.darkGray
view.addSubview(container)
// now create all of the subviews, specifying a tag for each; and
let cellWidth = (containerWidth - (4.0 * ViewController.kMargin)) / 3.0
for column in 0 ..< 3 {
for row in 0 ..< 3 {
let cell = UIView(frame: CGRect(x: ViewController.kMargin + CGFloat(column) * (cellWidth + ViewController.kMargin), y: ViewController.kMargin + CGFloat(row) * (cellWidth + ViewController.kMargin), width: cellWidth, height: cellWidth))
cell.tag = row * 3 + column;
container.addSubview(cell)
}
}
// finally, create the gesture recognizer
let pan = UIPanGestureRecognizer(target: self, action: #selector(handlePan))
container.addGestureRecognizer(pan)
}
// Here's a Swift 3.0 version based on Rajesh Choudhary's answer:
func drawLine(onLayer layer: CALayer, fromPoint start: CGPoint, toPoint end:CGPoint) {
let line = CAShapeLayer()
let linePath = UIBezierPath()
linePath.move(to: start)
linePath.addLine(to: end)
line.path = linePath.cgPath
line.fillColor = nil
line.lineWidth = 8
line.opacity = 0.5
line.strokeColor = UIColor.red.cgColor
layer.addSublayer(line)
}
var gesturedSubviews : [UIView] = []
var startX: CGFloat!
var startY: CGFloat!
var endX: CGFloat!
var endY: CGFloat!
func handlePan(gesture: UIPanGestureRecognizer) {
if (gesture.state == .began)
{
gesturedSubviews = [];
let location = gesture.location(in: gesture.view)
print("location \(location)")
startX = location.x
startY = location.y
}
if (gesture.state == .changed) {
let location = gesture.location(in: gesture.view)
print("location \(location)")
endX = location.x
endY = location.y
drawLine(onLayer: view.layer, fromPoint: CGPoint(x: startX, y: startY), toPoint: CGPoint(x:endX, y:endY))
startX = endX
startY = endY
}
if (gesture.state == .ended) {
let location = gesture.location(in: gesture.view)
print("location \(location)")
drawLine(onLayer: view.layer, fromPoint: CGPoint(x: startX, y: startY), toPoint: CGPoint(x:location.x, y:location.y))
}
// now figure out whether:
// (a) are we over a subview; and
// (b) is this a different subview than we last were over
let location = gesture.location(in: gesture.view)
print("location \(location)")
for subview in (gesture.view?.subviews)! {
if subview.frame.contains(location) {
if (subview != gesturedSubviews.last) {
gesturedSubviews.append(subview)
subview.backgroundColor = UIColor.blue
subview.alpha = 1.0
}
}
}
}
}
What I need is when a UIImageView is dragged off of the screen it to bounce back when it gets let go. I have it working in the left and top sides this is what I am doing.
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
if (!CGRectContainsPoint(self.view.frame, imageView.frame.origin)){
CGFloat newX = 0.0f;
CGFloat newY = 0.0f;
// If off screen upper and left
if (imageView.frame.origin.x < 0.0f){
CGFloat negX = imageView.frame.origin.x * -1;
newX = negX;
}else{
newX = imageView.frame.origin.x;
}
if (imageView.frame.origin.y < 0.0f){
CGFloat negY = imageView.frame.origin.y * -1;
newY = negY;
}else{
newY = imageView.frame.origin.y;
}
CGRect newPoint = CGRectMake(newX, newY, imageView.frame.size.width, imageView.frame.size.height);
[UIView beginAnimations:#"BounceAnimations" context:nil];
[UIView setAnimationDuration:.5];
[letterOutOfBounds play];
[imageView setFrame:newPoint];
[UIView commitAnimations];
}
}
}
So I would like to achieve the same thing for the right and bottom sides. But I have been stuck at this for awhile. Any Ideas?
How about something like the following?
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
UIImageView *imageView = nil;
BOOL moved = NO;
CGRect newPoint = imageView.frame;
// If off screen left
if (newPoint.origin.x < 0.0f){
newPoint.origin.x *= -1.0;
moved = YES;
}
// if off screen up
if (newPoint.origin.y < 0.0f){
newPoint.origin.y *= -1.0;
moved = YES;
}
// if off screen right
CGFloat howFarOffRight = (newPoint.origin.x + newPoint.size.width) - imageView.superview.frame.size.width;
if (howFarOffRight > 0.0)
{
newPoint.origin.x -= howFarOffRight * 2;
moved = YES;
}
// if off screen bottom
CGFloat howFarOffBottom = (newPoint.origin.y + newPoint.size.height) - imageView.superview.frame.size.height;
if (howFarOffBottom > 0.0)
{
newPoint.origin.y -= howFarOffBottom * 2;
moved = YES;
}
if (moved)
{
[UIView beginAnimations:#"BounceAnimations" context:nil];
[UIView setAnimationDuration:.5];
[letterOutOfBounds play];
[imageView setFrame:newPoint];
[UIView commitAnimations];
}
}
As I read your code, the logic of "if off the left side, move it back on to the view by the same distance it was off the screen." To be honest, that doesn't quite make sense to me (why, when bouncing back, does the coordinate depend upon how far off the screen it was), but I've tried to honor that in the "off screen right" and "off screen bottom" logic. Obviously my logic is using the superview of imageView to determine the width of the containing view, but if that's not appropriate, replace it with whatever is.
Edit:
I personally do this stuff with gesture recognizers, such as:
UIPanGestureRecognizer *pan = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(handlePan:)];
[self.imageView addGestureRecognizer:pan];
self.imageView.userInteractionEnabled = YES;
Thus, a gesture recognizer to animate moving the image back would be:
- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static CGRect originalFrame; // you could make this an ivar if you want, but just for demonstration purposes
if (gesture.state == UIGestureRecognizerStateBegan)
{
originalFrame = self.imageView.frame;
}
else if (gesture.state == UIGestureRecognizerStateChanged)
{
CGPoint translate = [gesture translationInView:gesture.view];
CGRect newFrame = originalFrame;
newFrame.origin.x += translate.x;
newFrame.origin.y += translate.y;
gesture.view.frame = newFrame;
}
else if (gesture.state == UIGestureRecognizerStateEnded || gesture.state == UIGestureRecognizerStateCancelled)
{
CGRect newFrame = gesture.view.frame;
newFrame.origin.x = fmaxf(newFrame.origin.x, 0.0);
newFrame.origin.x = fminf(newFrame.origin.x, gesture.view.superview.bounds.size.width - newFrame.size.width);
newFrame.origin.y = fmaxf(newFrame.origin.y, 0.0);
newFrame.origin.y = fminf(newFrame.origin.y, gesture.view.superview.bounds.size.height - newFrame.size.height);
// animate how ever you want ... I generally just do animateWithDuration
[UIView animateWithDuration:0.5 animations:^{
gesture.view.frame = newFrame;
}];
}
}
Or, if you want a gesture recognizer that just prevents the dragging of the image off the screen in the first place, it would be:
- (void)handlePan:(UIPanGestureRecognizer *)gesture
{
static CGRect originalFrame;
if (gesture.state == UIGestureRecognizerStateBegan)
{
originalFrame = self.imageView.frame;
}
else if (gesture.state == UIGestureRecognizerStateChanged)
{
CGPoint translate = [gesture translationInView:gesture.view];
CGRect newFrame = originalFrame;
newFrame.origin.x += translate.x;
newFrame.origin.x = fmaxf(newFrame.origin.x, 0.0);
newFrame.origin.x = fminf(newFrame.origin.x, gesture.view.superview.bounds.size.width - newFrame.size.width);
newFrame.origin.y += translate.y;
newFrame.origin.y = fmaxf(newFrame.origin.y, 0.0);
newFrame.origin.y = fminf(newFrame.origin.y, gesture.view.superview.bounds.size.height - newFrame.size.height);
gesture.view.frame = newFrame;
}
}
By the way, in iOS 7, you can give the animation of the image view back to its original location a little bounciness by using the new animationWithDuration with the usingSpringWithDampening and initialSpringVelocity parameters:
[UIView animateWithDuration:1.0
delay:0.0
usingSpringWithDamping:0.3
initialSpringVelocity:0.1
options:0
animations:^{
// set the new `frame` (or update the constraint constant values that
// will dictate the `frame` and call `layoutViewsIfNeeded`)
}
completion:nil];
Alternatively, in iOS7, you can also use UIKit Dynamics to add a UISnapBehavior:
self.animator = [[UIDynamicAnimator alloc] initWithReferenceView:self.view];
self.animator.delegate = self;
UISnapBehavior *snap = [[UISnapBehavior alloc] initWithItem:self.viewToAnimate snapToPoint:CGPointMake(self.viewToAnimate.center.x, self.view.frame.size.height - 50)];
// optionally, you can control how much bouncing happens when it finishes, e.g., for a lot of bouncing:
//
// snap.damping = 0.2;
// you can also slow down the snap by adding some resistance
//
// UIDynamicItemBehavior *resistance = [[UIDynamicItemBehavior alloc] initWithItems:#[self.viewToAnimate]];
// resistance.resistance = 20.0;
// resistance.angularResistance = 200.0;
// [self.animator addBehavior:resistance];
[self.animator addBehavior:snap];
I think the easiest way is to check whether your imageView has gone out of your self.view.
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
if (!CGRectContainsRect(self.view.frame, imageView.frame)){
// Your animation to bounce.
}
}
I do have a strange problem. I programmed a a dockview.
It's basically a NSView with three vertical subviews inside. So I have a left dock, a middle view and a right dock. Both docks are collapsable. The middle view gets resized while collapsing.
I'm using CoreAnimation to animate the collapsing process. This works almost correct.
If I uncollapse the left dock, the right docks drawRect method gets called although it's not dirty.
If I deactivate the animator and set the new frame size directly, the right dock not gets redrawn while uncollapsing so I assume the calculation of the frames is correct.
Here is my code for collapsing the docks:
- (void) mouseDown:(NSEvent *)event
{
// Exit method if already animating a dock
if(is_animating)
{
return;
}
NSPoint firstPoint = [self convertPoint:[event locationInWindow] fromView:nil];
unsigned long divider = [self mousePointInCollapseRect:firstPoint];
// If not clicked on a divider don't animate anything
if(divider == NSNotFound)
{
return;
}
NSView* main_view = [[self subviews] objectAtIndex:VIEW_MIDDLE];
NSView* collapse_view = [[self subviews] objectAtIndex:(divider == 0)? VIEW_LEFT : VIEW_RIGHT];
NSRect cframe = [collapse_view frame]; // New collapsable frame
NSRect mframe = [main_view frame]; // New main frame
if([self isSubviewCollapsed:collapse_view] == NO)
{
if(divider == 0)
{
cframe.size.width = 0.0;
mframe.origin.x -= (dock_width_left + DIVIDER_THICKNESS);
mframe.size.width += (dock_width_left + DIVIDER_THICKNESS);
}
else
{
mframe.size.width += (collapse_view.frame.size.width + DIVIDER_THICKNESS);
cframe.size.width = 0.0;
cframe.origin.x = mframe.origin.x + mframe.size.width;
}
// Turn off autoresizesSubviews on the collapsible subview
[collapse_view setAutoresizesSubviews:NO];
[NSAnimationContext beginGrouping];
[[NSAnimationContext currentContext] setDuration:(ANIMATION_DURATION)];
[[collapse_view animator] setFrame:cframe];
[[main_view animator] setFrame:mframe];
[NSAnimationContext endGrouping];
}
else
{
// Uncollapse dock
if(divider == 0)
{
// Left dock
cframe.size.width = dock_width_left;
mframe.origin.x = (COLLAPSEBAR_THICKNESS + dock_width_left + DIVIDER_THICKNESS);
mframe.size.width -= (dock_width_left + DIVIDER_THICKNESS);
}
else
{
// Right dock
mframe.size.width -= (dock_width_right + DIVIDER_THICKNESS);
cframe.size.width = dock_width_right;
cframe.origin.x = mframe.origin.x + mframe.size.width + DIVIDER_THICKNESS;
}
[NSAnimationContext beginGrouping];
[[NSAnimationContext currentContext] setDuration:ANIMATION_DURATION];
[[main_view animator] setFrame:mframe];
[[collapse_view animator] setFrame:cframe];
[NSAnimationContext endGrouping];
//Restore Autoresizing on subview
[self performSelector:#selector(restoreAutoResizingOfSubview:) withObject:collapse_view afterDelay:ANIMATION_DURATION + 0.05];
}
is_animating = YES;
[self performSelector:#selector(animationEnded) withObject:nil afterDelay:ANIMATION_DURATION + 0.05];
}
So why gets a non-dirty view redrawn?
I've been reading this book on game programming, but the examples are not that great. I'm working on one that calls [self setNeedsDisplay] but it cause the app the crash.
This is all the code I have, copied verbatim from the book:
-(void)awakeFromNib {
//start timer that will fire every second
[car setAlpha:0];
[road setAlpha:0];
currentImage = [UIImage imageNamed:#"road.png"];
//start timer that fires every second
[NSTimer scheduledTimerWithTimeInterval:(1.0) target:self selector:#selector(onTimer) userInfo:nil repeats:YES];
//start timer that fires every hundreth of a second
[NSTimer scheduledTimerWithTimeInterval:(0.01) target:self selector:#selector(onTimerRoad) userInfo:nil repeats:YES];
}
-(void)onTimerRoad
{
int tileIndex;
tileIndex += 1;
[self setNeedsDisplay];
}
-(void)onTimer {
[self update];
[self draw];
}
-(void)update {
[self updateRoad];
}
-(void)updateRoad {
[self randomRoadUpdate];
}
-(void)randomRoadUpdate {
int distance = (random() % 11) -5;
CGPoint oldPosition = road.center;
if (oldPosition.x + distance < 96 || oldPosition.x + distance > 224)
return;
road.center = CGPointMake(oldPosition.x + distance, oldPosition.y);
}
-(void)draw {
}
- (id) initWithFrame:(CGRect)frame {
if (self = [super initWithFrame:frame]) {
//init code
}
return self;
}
-(void)drawRect:(CGRect)rect {
CGImageRef image = CGImageRetain(currentImage.CGImage);
CGRect imageRect;
imageRect.origin = CGPointMake(160, 240);
imageRect.size = CGSizeMake(320.0, 480.0);
CGContextRef uiContext = UIGraphicsGetCurrentContext();
CGContextClipToRect(uiContext, CGRectMake(0.0, 0.0, rect.size.width, rect.size.height));
CGContextDrawTiledImage(uiContext, imageRect, image);
}
Turns out instead of [self setNeedsDisplay] I need to do [self.view setNeedsDisplay]