Add action to a programmatically created ImageView - ios

Question

I have created image view through code like this -
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib
UIImageView *dot =[[UIImageView alloc] initWithFrame:CGRectMake(50,50,20,20)];
dot.image=[UIImage imageNamed:#"draw.png"];
[self.view addSubview:dot];
}
I want to add User Interaction to this UIImageView and then create a selector or action for this UIImageView when tapped how is this done?

Answer 1

It depends on what kind of action you want achieve. Generally speaking you'd be using UIGestureRecognizer. For instance if you want your image to respond to a tap gesture then you'd have something like the following.
- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib
dotArray = [NSMutableArray alloc]init];
UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(handleTapGesture:)];
for(int i = 0; i< 30; i++) {
UIImageView *dot =[[UIImageView alloc] ...
dot.image=[UIImage imageNamed:#"draw.png"];
dot.tag = i; //identify dot image.
[self.view addSubview:dot];
[dotArray addObject:dot];
[dot addGestureRecognizer:tapGesture];
...
}
[tapGesture release];
}
Then the methods to handle tap gesture...
-(void)handleTapGesture:(id)sender {
UITapGestureRecognizer * tapGesture = (UITapGestureRecognizer*)sender;
for(int i = 0; i<[dotArray count]; i++) {
UIImageView * dot = (UIImageView*)[dotArray objectAtIndex:i];
if(dot.tag == [tapGesture view].tag) {
//fade out animation
[UIView beginAnimations:nil context:NULL];
[UIView setAnimationDuration:0.5f];
dot.alpha = 0.0f;
[UIView commitAnimations];
}
For this to work, you need to make an array of dots and declare it as instance variable, otherwise the method can't access the dot.

Answer 2

Try like this:-
UIImageView *dot =[[UIImageView alloc] initWithFrame:CGRectMake(50,50,20,20)];
dot.image=[UIImage imageNamed:#"draw.png"];
[self.view addSubview:dot];
1) To implement the number of touch required is 1 refer this:-
UITapGestureRecognizer *doubleTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(scrollViewDoubleTapped:)];
doubleTapRecognizer.numberOfTapsRequired = 2;
doubleTapRecognizer.numberOfTouchesRequired = 1;
[dot addGestureRecognizer:doubleTapRecognizer];
- (void)doubleTapped:(UITapGestureRecognizer*)recognizer
{
}
2) To implement the number of touch required is 2 refer this:-
UITapGestureRecognizer *twoFingerTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(scrollViewTwoFingerTapped:)];
twoFingerTapRecognizer.numberOfTapsRequired = 1;
twoFingerTapRecognizer.numberOfTouchesRequired = 2;
[dot addGestureRecognizer:twoFingerTapRecognizer];
- (void)twoFingerTapped:(UITapGestureRecognizer*)recognizer
{
}

Answer 3

Thank you all of you that helped me I put everyones answers together and got this as my final code.
//
// ViewController.m
// InvaderRush
//
// Created by Ajay Venkat on 13/12/2014.
// Copyright (c) 2014 AJTech. All rights reserved.
//
#import "ViewController.h"
#interface ViewController ()
{
NSArray *dotArray;
}
#end
#implementation ViewController
- (void)viewDidLoad {
UIImageView *dot =[[UIImageView alloc] initWithFrame:CGRectMake(50,50,100,100)];
dot.image=[UIImage imageNamed:#"invader.jpg"];
[self.view addSubview:dot];
dot.tag = 1; //identify dot image.
UITapGestureRecognizer *doubleTapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:#selector(doubleTapped:)];
doubleTapRecognizer.numberOfTouchesRequired = 1;
[dot addGestureRecognizer:doubleTapRecognizer];
dot.userInteractionEnabled = YES;
NSMutableArray *images =[[NSMutableArray alloc] initWithObjects: dot,nil];
}
- (void)didReceiveMemoryWarning {
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
-(void)doubleTapped:(id)sender {
UIGestureRecognizer *recognizer = (UIGestureRecognizer*)sender;
UIImageView *imageView = (UIImageView *)recognizer.view;
if(imageView.tag==1) {
[imageView setImage:[UIImage imageNamed:#"space_invader.jpg"]];
}
}
-(void)handleTapGesture:(id)sender {
}
#end