Apps Referencing Resource Via String

[safibaba]

I was just wondering if there is any way to reference a resource using a string.

Say you had 10 images in your drawable folder called 'img1' 'img2' 'img3' etc......

int imgNum = 2;
String imgName = "img"+imgNum;
Drawable d = (Drawable) getResources().getDrawable(R.drawable.imgName);

Is there any way of doing this? Or will I just have to use if statements to work out which image to use?

 

[markb]

Hi,

It might be overkill, but if you want something that will scale up to handle lots of resources then you could use Java reflection.

I describe a solution in another thread:

http://androidforums.com/android-de...lements-res-raw-folder-one-shot-run-time.html

You'd have to adapt the code a little. Instead of:

Field fields[] = R.raw.class.getDeclaredFields() ;

You'd have to use:

Field fields[] = R.raw.drawable.getDeclaredFields() ;

If you're familiar with Java reflection then hopefully that other thread will give you an idea of how to achieve what you want.

I can explain further if you like. Just ask.

Regards,

Mark

 

[Boogs]

To answer your first question: no, I don't know a way to reference your drawables by a String.

To answer your second question: I use Maps to handle problems like yours where I know there are going to be multiple statically paired items.

For example, I might declare the global variable:

public static final String PREFIX = "img";
public static final Map mImageMap = new HashMap<String, Drawable>();

...then, in onCreate I'd pay the one time setup fee by putting:

if (mImageMap.size() == 0) {
   mImageMap.put(PREFIX + "1", getResources().getDrawable(R.drawable.img1));
   mImageMap.put(PREFIX + "2", getResources().getDrawable(R.drawable.img2));
   mImageMap.put(PREFIX + "3", getResources().getDrawable(R.drawable.img3));
}

and then finally when I want to reference the value, I would do something like:

int exampleInput = 2;
Drawable d = mImageMap.get(PREFIX + exampleInput);

 

[safibaba]

Ahh - hashmap - that's a great idea!

I'm so used to working a a language where this is possible, I didn't even think of making a dictionary / hash.

Thanks Boogs. I actually just wrote a factory method to return the relevant image, since there were only three, but I will need to do one with much more images soon, so this will be a great solution, and much easier to maintain.

Cheers