Unknown class R.string ... when extracting string resource

Question

I am trying to extract a string resource out of my activity but get the following error -

I don't remmber in the past that there was anything that I should have filled before the dot of the "getString" method for extracting a string out of an activity. What am I missing?

String from another activity or string from the string resource file? — tiborK
– tiborK, Commented Aug 27, 2019 at 19:01

Gabriele Mariotti · Accepted Answer · 2019-08-27 19:24:34Z

2

You can use:

String myValue = getResources().getString(R.string.mystring);

but getResources() is a method of the Context class.

It means that you can't do this:

private static String BASE_URL = getResources().getString(R.string.myurl); //it DOESN'T work!!

You can use your BuildConfig class to set these kind of values.
Also in your build.gradle file you can config them:

buildTypes {
    release {
      //..
      buildConfigField("String", "BASE_URL", "....")
    }
    //....
}

It will populate BuildConfig.BASE_URL.

edited Aug 27, 2019 at 19:24

answered Aug 27, 2019 at 19:18

Gabriele Mariotti

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2 Comments

Alon Shlider Over a year ago

I have tried your solution and here is my line of code - ' public String BASE_URL = getResources().getString(R.string.hero_apps_api); ' but still getting a NPE. What am I missing? I am declaring the variable before onCreate, if it matters.

Alon Shlider Over a year ago

alright, answered to myself. I need to put it inside the lifecycle. Thanks! works.

tiborK · Accepted Answer · 2019-08-27 19:04:28Z

1

If you want to use another constant declared in another activity make sure that is declared public and import it.

If you wand to use a string declared in the string resource file:

    getResources().getString(R.string.mystring);

answered Aug 27, 2019 at 19:04

tiborK

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2 Comments

Alon Shlider Over a year ago

your solution gives the following error - 'NPE - Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference'

tiborK Over a year ago

If you are getting it from the resource file you don't need to assign it to a constant. Retrieve it when you need it.

Tamir Abutbul · Accepted Answer · 2019-08-27 19:02:51Z

0

Try to call getResources() like this:

Java

String yourString = getResources().getString(R.string.herro_app_aoi);

kotlin

val yourString = resources.getString(R.string.herro_app_aoi)

answered Aug 27, 2019 at 19:02

Tamir Abutbul

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5 Comments

Alon Shlider Over a year ago

your solution gives the following error - 'NPE - Attempt to invoke virtual method 'android.content.res.Resources android.content.Context.getResources()' on a null object reference'

Tamir Abutbul Over a year ago

I was sure that you are using activity. Are you using a fragment ? if so check this thread

Alon Shlider Over a year ago

I am using a string from the resouce file and when trying your method I got the NPE I posted to your comment

Alon Shlider Over a year ago

I am using an activity

Tamir Abutbul Over a year ago

My code works fine for me, have you checked What is a NullPointerException, and how do I fix it?

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