I have a button with an image, and after a little while the button image will change, then change back after a few seconds. I want to be able to tell if the button is clicked while the image is different. thanks!
You have several options, but I'll detail two of them. The first is more self-contained and foolproof, but the second is arguably easier to read and understand.
Check the background image
The easiest way to do this would probably be to just test against the image itself. The image changes from time to time, but you don't really care when the button is pressed, you just care which background is visible when it is.
In other words, all you really need to know is whether the button's background is the MainBackground or the AlternateBackground, so when the button is pressed, you can simply check which one it is.
Try something like this, for when the button is pressed:
-(void)buttonPressed:(UIButton*)sender {
UIImage *mainBackground = [UIImage imageNamed:#"YOUR_IMAGE_NAME"];
NSData *imgdata1 = UIImagePNGRepresentation(sender.image);
NSData *imgdata2 = UIImagePNGRepresentation(mainBackground);
if ([imgdata1 isEqualToData:imgdata2]) {
// The button's background is the MainBackground, do one thing
} else {
// The button's background is the AlternateBackground, do another thing
}
}
Keep track of which image is currently displayed
Alternatively, you could have a BOOL value flip whenever the image's background is changed. Something like...
#property BOOL isMainBackground;
...in your H file, and then whenever you set the button's background image, you also set self.isMainBackground = YES; or self.isMainBackground = NO;
Then, your method for the button press would look something like this:
-(void)buttonPressed:(UIButton*)sender {
if (self.isMainBackground) {
// The button's background is the MainBackground, do one thing
} else {
// The button's background is the AlternateBackground, do another thing
}
}
Related
I have a situation that is confusing me lots. I have a class that has 2 completely separate things: An animated UIImage and a UILabel. They have different outlets, are not connected.
When the app runs, it does this:
dispatch_async(dispatch_get_main_queue(), ^{
[self.monsterMachine setHidden:NO]; //monsterMachine is UIImageView
[self.monsterMachine startAnimating];
});
but then when I do this:
[self.futText setText:#"blah"]; // is UILabel
it causes the monsterMachine UIImageView to not animate anymore. Things I have found:
Right after I setText:#blah" I can use NSLog to watch and see that self.monsterMachine.isAnimated suddenly goes from 1 to 0, ie from YES to NO.
If self.futText is ALREADY saying "blah", then I can run setText:#"blah" on it as many times as I want and nothing happens, it is ONLY when I change it to some value other than blah that UIImageView stops animating and disappears
If I don't use main_queue to show and animate monsterMachine, it won't display at ALL, so how do I diagnose or fix this?
That's weird it works for me perfect. Did you call [self.futText setText:#"blah"]; in main queue also?
Here is a small answer to why setting text #"blah" won't stops the animation:
Strings like #"blah" are stored in stacks which have the same reference as long as they have the same context. In this case [self.futText setText:#"blah"] will do nothing because the internal implementions are like:
void setText:(NSString*) text {
if ( _text == text ) then return;//if reference is the same then do nothing
_text = text;
some rendering..
}
I have an outlet called myImage for an imageView that is set up with an animation of 5 images. With a Tap Gesture Recognizer on it, I want to have the users tap on the correct image as it quickly passes to move onto the next level.
There is an error in my code and this does not work:
- (void)viewDidLoad {
[super viewDidLoad];
self.myImage.animationImages =
[NSArray arrayWithObjects:
[UIImage imageNamed:#"examplePic1.png"],
[UIImage imageNamed:#"examplePic2.png"],
[UIImage imageNamed:#"correctPic.png"],
[UIImage imageNamed:#"examplePic4.png"],
[UIImage imageNamed:#"examplePic5.png"],
nil];
[self.myImage setAnimationRepeatCount:0];
self.myImage.animationDuration = 1;
[self.myImage startAnimating];
}
- (IBAction)TapGestureRecognizer:(id)sender {
if (self.myImage.image = [UIImage imageNamed:#"correctPic.png"]) {
// Launch next level
}
else {
// Vibrate Device and subtract points from score
}
}
You have a fundamental misconception in your code about objects and equality. I assume that you meant "==" in your TapGestureRecognizer method. However, even if you changed the = to == would not give you what you want.
The expressions like
[UIImage imageNamed:#"examplePic1.png"]
call a class method of UIImage that creates a new UIImage object. You have created 5 of these objects, put them into an array, an set the animationImage array of your UIImage object to these images. These objects are all different objects from myView.image: I can tell because I can see from your code that you have assigned 5 new objects to the animationObjects array. Your == test cannot ever work because you are comparing self.image to a brand new UIImage object.
What you are trying to do is determine which image the user touched. There is no method in UIImageView that tells you which animation UIImage is currently showing. You are assuming that the image property of the view will be changed as the animation images are displayed, but there is no reason for this assumption to be true: it is certainly not stated in the documentation. Even if you corrected your code (by doing something like this):
if(self.image == [self.animationImages objectAtIndex:2]){
}
your code would not be correct.
If I were trying to do what you want, I would create a UIView with 5 UIImageView as subview, each with their own gesture recognizer. I would use the frame property of each subview to do my animation.
Looks like the options are to determine which image "should" be showing based upon the startTime of the animation.
Determine which of its animationImages a UIImageView is displaying?
Or, just use a timer to set the currently displayed image.
Detect which image was clicked in UIImageView with animationImages
So i am creating a tic tac toe game (user vs computer) and i want to have -(IBAction) statements with if statements thats would say if(buttonIsPressed), do ____. I cant just say
-(IBAction)button:(id)selector;{
//stuff i want
}
because the buttons are pressed in different order and the computer would have different responses (i want there to be an order). For example, this is what i tried,
-(IBAction)move2;{
if (buttona2){
c2.image = [UIImage imageNamed:#"imgres-3.jpg"];
}
it didnt work because the the result of this if statement ( c2.image = [UIImage imageNamed:#"imgres-3.jpg"];) would start automatically and not run depending on the pressing of the button (it runs right away). Pretty much i want the if statement to run on press of a button (or not work if the button is not pressed.
Can anyone help?
If I understand your question right, you want to check if a button is toggled on or off before running the if statement right? In that case, I would declare a BOOL in your header file
#property BOOL toggle;
Then in your implementation file when the user presses the button the target of the button should have the code:
if(self.toggle == TRUE){
self.toggle = FALSE;
//and any visual UI change you want to show that the button is now off
}else{
self.toggle = TRUE;
//and any visual change you want to show that the button is now on
}
Then in your -(IBAction) your code becomes:
-(IBAction)move2;{
if (self.toggle){
c2.image = [UIImage imageNamed:#"imgres-3.jpg"];
}
}
And that should work.
I'm working on a painting app, and I want to user to be able to switch through paintings that are saved as PNGs to the documents directory. I've made an IBAction that does this:
-(IBAction)switchPage:(id)sender{
if ([sender tag] ==1)
{
currentImage=currentImage-1;
}
else
{
currentImage++;
}
[[NSUserDefaults standardUserDefaults] setInteger:currentImage forKey:#"currentDoc"];
[self.view setNeedsDisplay];
}
Just to let you know, I have 2 buttons, a back and forward, and they're connected to the same IBAction that's pasted above. The back button has a tag of 1, and the forward button doesn't have a tag. currentImage is an int that is used to set an image's name, so if currentImage =1, then it would set the image to image1. But that's not what I'm having trouble with, I'm having trouble "reloading" the view. I'm using setNeedsDisplay, but it's not working, and I know that reloadData is only for UITables, so what else could I use?
I've been searching for an answer, but none of the existing questions about this don't have a clear answer, or are under different circumstances.
Thanks for your time and/or dealing with a stupid question, as I'm new to Xcode.
-Karl
I see no view code in your post.
Assuming you have a UIImageView that is displaying the image you would just do:
myImageView.image = whateverUIImage;
I've set a button with an image as it's background, and I'm trying to get the image to change back and forth from 2 different images when pressed.
For example, a happy face when pressed would switch to a sad face, and when pressed again would switch back to a happy face and so on.
Any help you can offer would be amazing before I pull anymore hair out.
set the images for two different states: normal and selected,
have the button target an action that toggles the selected state on the button/sender
UIButton* myButton;
- (IBAction)buttonPressed {
if(alreadySelected) {
myButton.imageView.image = myNormalImage;
} else {
myButton.imageView.image = mySelectedImage;
}
}
Not sure, but I think this should do it.
What BoopMeister said, except as bshirley pointed out, you need this API call:
[myButton setImage:happyImage forState:UIControlStateNormal];