CODEWITHSUNDEEP
javaandroidandroid-resources
fadedbee
fadedbee

Reputation: 44739

Android, get resource id by string?

Is there a better way to do this:

    int drawable;
    switch(mSignalStrength) {
        case 0:
            drawable = R.drawable.signal_0;
            break;
        case 1:
            drawable = R.drawable.signal_1;
            break;
        case 2:
            drawable = R.drawable.signal_2;
            break;
        case 3:
            drawable = R.drawable.signal_3;
            break;
        case 4:
            drawable = R.drawable.signal_4;
            break;
        case 5:
            drawable = R.drawable.signal_5;
            break;
        default:
            drawable = -1;
    }

I'm trying to replace the switch statement with some int getDrawableIdByString("signal_" + mSignalStrength) function.

Upvotes: 3

Views: 6902

Answers (3)

Phantômaxx
Phantômaxx

Reputation: 38098

By using reflection, you can return the resource id by passing its name.
This is what I use when I need something like that:

1 - Add this method to your code:

protected final static int getResourceID
(final String resName, final String resType, final Context ctx)
{
    final int ResourceID =
        ctx.getResources().getIdentifier(resName, resType,
            ctx.getApplicationInfo().packageName);
    if (ResourceID == 0)
    {
        throw new IllegalArgumentException
        (
            "No resource string found with name " + resName
        );
    }
    else
    {
        return ResourceID;
    }
}

2 - Use it like this:

int myID =
    getResourceID("your_resource_name", "drawable", getApplicationContext());

Note (1): no path (and no extension, in case of images).
Note (2): use "drawable" for drawables, "string" for strings, ...

Upvotes: 2

JoeyJubb
JoeyJubb

Reputation: 2321

The way you're doing it is the most readable and robust way.

It allows you to add / remove items later down the line and doesn't tie you in to a specific naming convention.

It's easier to read because you can just click through to the drawable resource from the code and see for yourself exactly which drawable matches which case -- something that becomes a bit harder when you're generating the id this way.

Upvotes: 0

Marko
Marko

Reputation: 20513

As someone mentioned in the comments, you can use the

getIdentifier(String name, String defType, String defPackage)

For you case, like this

int resId = getResources().getIdentifier("signal_" + mSignalStrength, "drawable", getPackageName());

Upvotes: 8

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