Getting a drawable using for loop index

Question

I am designing UI and for that need to populate some dummy content for recyclerview. So I thought to create using for loop so it makes life easier if I want to change the number.

I have drawable resources (images) that suffix with numbers. for instance

avatar_1, avatar_2, avatar_3, ...
featured_1, featured_2, featured_3, ...

I have tried setting R.drwable.featured_ + i and as expected it didn't work and end up with an error.

This is what I am using

...

for (int i = 0; i <= 11; i++) {

    int username = random.nextInt(userNames.length);
    int catInt   = random.nextInt(categories.length);
    int time     = random.nextInt(times.length);

    mBlogs.add(new Blog(
            R.drawable.featured_ + i, // this
            R.drawable.avatar_ + i, // this
            getString(R.string.blog_title),
            categories[catInt],
            getString(R.string.blog_excerpt),
            userNames[username],
            times[time],
            random.nextBoolean(),
            random.nextBoolean()
    ));
}

...

Question: How can I get resource within the loop by loop index?

Why a negative vote? What is wrong with this question?

Code Lover
– Code Lover

2020-03-06 08:49:13 +00:00
Commented Mar 6, 2020 at 8:49 — Code Lover
– Code Lover, Commented Mar 6, 2020 at 8:49

Community · Accepted Answer · 2020-06-20 09:12:55Z

2

Try as below.

//find drawable resource id 
public int getDrawableId(Context context, String name) 
{
    try {
        return getResources().getIdentifier(name, "drawable", context.getPackageName());
    } catch (Exception e) {
        e.printStackTrace();
        return -1;
    } 
}

...
for (int i = 0; i <= 11; i++) {
    int username = random.nextInt(userNames.length);
    int catInt   = random.nextInt(categories.length);
    int time     = random.nextInt(times.length);
    int featuredRes = getDrawableId(context, "featured_" + i);
    int avatarRes = getDrawableId(context, "avatar_" + i);

    // if not found any resource
    if (featuredRes == 0) featuredRes = R.drawable.featured_default

    if (avatarRes == 0) avatarRes = R.drawable.avatar_default

    mBlogs.add(new Blog(
            featuredRes,
            avatarRes,
            getString(R.string.blog_title),
            categories[catInt],
            getString(R.string.blog_excerpt),
            userNames[username],
            times[time],
            random.nextBoolean(),
            random.nextBoolean()
    ));
}
...

edited Jun 20, 2020 at 9:12

CommunityBot

11 silver badge

answered Mar 6, 2020 at 8:34

Ethan Choi

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1 Comment

Code Lover Over a year ago

Although the logic is the same as @shb since your code looks more organized that reduce the code duplication. Thanks a lot.

shb · Accepted Answer · 2020-03-06 09:11:26Z

1

You can use getIdentifier

for (int i = 0; i <= 11; i++) {
    int featuredResId = getResources().getIdentifier("featured_" + i, "drawable", getPackageName())
    int avatarResId = getResources().getIdentifier("avatar_" + i, "drawable", getPackageName())
    //...
    mBlogs.add(new Blog(
            featuredResId,
            avatarResId,
            //...
    ));
}

edited Mar 6, 2020 at 9:11

answered Mar 6, 2020 at 8:26

shb

6,2872 gold badges17 silver badges35 bronze badges

3 Comments

Code Lover Over a year ago

Thanks a lot for your help and reference code. I am unable to set getPackageName() it shows error cannot resolve method. For your reference, I am using this code in the fragment.

shb Over a year ago

use getActivity().getPackageName()

Code Lover Over a year ago

Ah. I have to use getActivity().getPackageName()

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Getting a drawable using for loop index

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Try as below.

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Try as below.

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