How do I use touchlistener to load new images on my Java Android app?

  • Java
  • Thread starter whitehorsey
  • Start date
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    Android Java
In summary, the conversation discusses the process of loading images on an app, specifically in a series of choices where the first set of images are loaded and then replaced by another set upon selecting one of the images. The conversation also touches on using a touch listener to trigger the loading of the new set of images. There is some uncertainty about the code and its functionality, but the conversation concludes with a suggestion to use breakpoints and an explicit refresh to troubleshoot any issues with the code.
  • #1
whitehorsey
192
0
On my app there are two rows that holds 3 images each (as seen in the image attachment). In the beginning, the 6 images are loaded and then when a person touches one of the images I want the other 6 images to be loaded. It's a series of choices. Ex. First 6 images would be to pick what day it is. After selecting the day, it would be replace the 6 images with 6 different choices for which month is it.

There is a series of choices in the series there is a list of the six choices that will be loaded.

images.jpg


I'm not sure how to use touchlistener so far I have this:

Code:
if(count > 1)
		{
			imageview.setOnTouchListener(new OnTouchListener()
			{
				
			    @Override
			    public boolean onTouch(View v, MotionEvent event) 
			    {
			        if(event.getAction() == MotionEvent.ACTION_UP)
			        {
			            count--;
			            return true;
			        }
			        return false;
			    }
			});
		}

If the there is more than one choice series (cause there will be some parts of the app where there won't be 6 new choices after selecting one), check to see if someone touched an image. However, the app right now loads the other choices from the series (day -> month) without waiting for someone to touch an image. How do I fix this?
 
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  • #2
I know nothing about developing for Android nor in Java, but I know a thing or two about parentheses, and I am not convinced they look OK.
 
  • #3
Borek said:
I know nothing about developing for Android nor in Java, but I know a thing or two about parentheses, and I am not convinced they look OK.
I thought that as well, but later decided they're probably OK. The OnTouchListener parameter

This part --
Code:
{
				
			    @Override
			    public boolean onTouch(View v, MotionEvent event) 
			    {
			        if(event.getAction() == MotionEvent.ACTION_UP)
			        {
			            count--;
			            return true;
			        }
			        return false;
			    }
			});
-- is an inline definition of the OnTouchListener method that is a parameter. The right brace on the last line matches the left brace at the top of what I copied. The right parenthesis matches the left parenthesis in setOnTouchListener(.

whitehorsey, your explanation of what you're trying to do is unclear.
whitehorsey said:
On my app there are two rows that holds 3 images each (as seen in the image attachment). In the beginning, the 6 images are loaded and then when a person touches one of the images I want the other 6 images to be loaded. It's a series of choices. Ex. First 6 images would be to pick what day it is. After selecting the day, it would be replace the 6 images with 6 different choices for which month is it.
After the 6 images are loaded and you touch one of the images, is the idea that 6 different images are to be loaded?

For something to happen when you touch one of the images, you need code in your OnTouch event handler to load the 6 new images. In your code, all that happens is that count is decremented.
 
Last edited:
  • #4
Mark44 said:
is an inline definition of the OnTouchListener method that is a parameter. The right brace on the last line matches the left brace at the top of what I copied. The right parenthesis matches the left parenthesis in setOnTouchListener(.

Yes, it occurred to me that it can work this way, but I am not convinced it is the intent, it looks more like the code was pasted in the wrong place, producing code that is accidentally syntactically correct.

Or at least, in my code I would put parentheses differently, to not leave this "accidental correctness" impression.

But as I wrote, I know nothing about Java. I just started to learn yesterday.
 
  • #5
whitehorsey, your explanation of what you're trying to do is unclear.
After the 6 images are loaded and you touch one of the images, is the idea that 6 different images are to be loaded?

Yep! I'm making a calendar so the first 6 images loaded are some random days of the week (mon, tues, etc.) . The person selects one of the days then it will load 6 random different images these will be to select the month.

For something to happen when you touch one of the images, you need code in your OnTouch event handler to load the 6 new images. In your code, all that happens is that count is decremented.

Thank You for catching that!

Code:
if(count > 1)
		{
			iv.setOnTouchListener(new OnTouchListener()
			{
				
			    @Override
			    public boolean onTouch(View v, MotionEvent event) 
			    {
			        if(event.getAction() == MotionEvent.ACTION_UP)
			        {
			        	count--;
			        	addImages(series.getList().get(index));
			            return true;
			        }
			        return false;
			    }
			});
		}

addImages passes the new 6 images. I tried touching the icons but nothing is happening.
 
  • #6
whitehorsey said:
addImages passes the new 6 images. I tried touching the icons but nothing is happening.

I/anyone would need to see the addImages method to see how the method passes the images.

If you don't want to post it it's okay, but put breakpoints on the addImages method code and click on the cockroach (or ladybug) of eclipse. Sometimes it happens that whatever control one is using needs an explicit refresh (like ListViews sometimes, depending on how it is being used).
 
Last edited:

1. What is a TouchListener in Java Android?

A TouchListener in Java Android is an interface that is used to handle touch events on a View. It allows you to capture and respond to different types of touch events, such as tapping, swiping, and dragging.

2. How do you implement a TouchListener in Java Android?

To implement a TouchListener in Java Android, you need to create a class that implements the View.OnTouchListener interface. Then, you need to override the onTouch() method and add your desired logic for handling touch events.

3. What are the different types of touch events that can be handled with a TouchListener?

A TouchListener can handle various types of touch events, including ACTION_DOWN (when a finger touches the screen), ACTION_MOVE (when a finger moves on the screen), and ACTION_UP (when a finger is lifted off the screen).

4. Can a single TouchListener handle touch events for multiple Views?

Yes, a single TouchListener can handle touch events for multiple Views. This can be achieved by setting the same TouchListener to each View using the setOnTouchListener() method.

5. How do you remove a TouchListener from a View in Java Android?

To remove a TouchListener from a View in Java Android, you can use the setOnTouchListener() method and pass in a null value. This will remove the previously set TouchListener and prevent any further touch events from being captured.

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