Changing images using for loop

Question

How to change an image to the next one in the array using a for loop, once a button has been clicked. At present I have this in my on click method.

 int[] Pics = {R.drawable.pic1, R.drawable.pic2, R.drawable.pic3};

 for (int i=0; i<Pics.length; i++){

     mainpic.setImageResource(Pics[i]);

 }

The problem is when the next button is clicked, it only stays at the first image or goes straight through to the last image.

because you should do it in the background and put delay every image chages — Ersin Gülbahar, Apr 30 '14 at 10:12

Matej Špilár · Accepted Answer · 2014-04-30T11:31:39.163

0

i quite dont get it ... you wrote that when you click the next button for next image its not working ... but what is not working ? this is for loop ... it will loop to the end of an array and set the image to the last image in it... what you need to define a class variable like

int[] Pics = {R.drawable.pic1, R.drawable.pic2, R.drawable.pic3};
int i = 0;
mainpic.setImageResource(Pics[i]);

then inside next button onClick method ..

 i++;
 if(i >=3) {
   i = 0;
 }
 mainpic.setImageResource(Pics[i]);

edited Apr 30 '14 at 11:31

answered Apr 30 '14 at 10:15

Matej Špilár

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this works perfect for looping through the images but give an out of bounds error when an intent is set at the if rather than i=0. Any ideas why? – user3535866 May 05 '14 at 15:47

Umer · Answer 2 · 2014-04-30T10:23:20.110

0

try this block of code you are missing new int[]

int[] Pics = new int[]{R.drawable.pic1, R.drawable.pic2, R.drawable.pic3};

and use this inside of loop

int i = 0;

onClick method

mainpic.setImageResource(Pics[i]);
i++

edited Apr 30 '14 at 10:23

answered Apr 30 '14 at 10:17

Umer

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thats not true ... you should read the ways how you can declare arrays in java ... http://stackoverflow.com/questions/1200621/how-to-declare-an-array-in-java – Matej Špilár Apr 30 '14 at 10:19
ok you are right we have two ways of declaring arrays int[] myIntArray = {1,2,3}; int[] myIntArray = new int[]{1,2,3}; – Umer Apr 30 '14 at 10:25

score 0 · Answer 3 · answered Apr 30 '14 at 10:49

You do not need for loop for this. Handle image change in onClick():

public void onClick(View view)
{
      if (view.getId() == R.id.<ButtonId>)
      {
           mainpic.setImageResource(Pics[currentImageIndex]);
           currentImageIndex = (currentImageIndex + 1) % Pics.Length;
      }
}

PS: currentImageIndex is a class variable. The % operation will allow you to change the image in a cyclic fashion.

Changing images using for loop

3 Answers3