Change value of R.string programmatically

Question

I have declared a string in my strings.xml file , and using it in my activity as R.string.compose_title. (setting it as title i.e. setTitle(R.id.compose_title)). Now in some case I want to edit the string and then use it to set the title . How can I do this ?

P.S. I need to change value of a single string only , So declaring a new strings.xml for each case(which are variable depending upon the user) using localization seems to be a lil inefficient .

Solution 1

One thing what you have to understand here is that, when you provide a data as a Resource, it can't be modified during run time. For example, the drawables what you have in your drawable folder can't be modified at run time. To be precise, the "res" folder can't be modified programatically.

This applies to Strings.xml also, i.e "Values" folder. If at all you want a String which has to be modified at runtime, create a separate class and have your strings placed in this Class and access during run time. This is the best solution what I have found.

Solution 2

example howto:

how? by changing one variable reference to other reference

usage:

setRColor(pl.mylib.R.class,"endColor",pl.myapp.R.color.startColor);
// override app_name in lib R class  
setRString(pl.mylib.R.class,"app_name",pl.myapp.R.string.app_name);

base methods:

public static void setRColor(Class rClass, String rFieldName, Object newValue) {
    setR(rClass, "color", rFieldName, newValue);
}

public static void setRString(Class rClass, String rFieldName, Object newValue) {
    setR(rClass, "string", rFieldName, newValue);
}

// AsciiStrings.STRING_DOLAR = "$";
public static void setR(Class rClass, String innerClassName, String rFieldName, Object newValue) {
    setStatic(rClass.getName() + AsciiStrings.STRING_DOLAR  + innerClassName, rFieldName, newValue);
}

helper methods :

public static boolean setStatic(String aClassName, String staticFieldName, Object toSet) {
    try {
        return setStatic(Class.forName(aClassName), staticFieldName, toSet);
    } catch (ClassNotFoundException e) {
        e.printStackTrace();
        return false;
    }
}

public static boolean setStatic(Class<?> aClass, String staticFieldName, Object toSet) {
    try {
        Field declaredField = aClass.getDeclaredField(staticFieldName);
        declaredField.setAccessible(true);
        declaredField.set(null, toSet);
        return true;
    } catch (Exception e) {
        e.printStackTrace();
        return false;
    }
}

@bradenV2 My app is supporting many languages , so I wanted to take a string from my strings.xml that's currently in use and change that , and then use that one – atuljangra Mar 12 '12 at 22:04

ps the above solution is good for example when u want to inject some data in already compiled lib/jar. But if u want localize strings just make folder under res per LANG CODE like values-CC where cc is lang code (values-de,values-cs) etc

then u have 2 choices:

1. "build in" system dependent language selection - based on device selected lang
2. via create resources for configuration - you decide which lang show

like this:

configuration = new Configuration(resources.getConfiguration());
configuration.setLocale(targetLocale);
String localized = Context.createConfigurationContext(configuration)
    .getResources()
    .getString(resourceId);

Solution 3

I don't think you can programmatically customize the R class as it is built by ADT automatically.

Solution 4

I had a situation like this, where one of my strings.xml values had some dynamic piece of it. I set up the strings.xml with a "replacement text" (something like %%REPLACEMENT_EMAIL%%), and when I wanted to use that string programatically, I retrieved the string value of the resource, and replaced instances of that replacement text with the dynamic value (e.g. input by the user).

To be honest, my app has not been localized yet, but I'm still attempting to follow best practices w.r.t. not hardcoding any strings.

Solution 5

Use SharedPreferences instead of a Java class. It will give you more versatility if you decide to take values from the outside (web). Filling Java class in runtime can be useless offline. In case of SharedPreferences you have to ensure they are loaded only once, during app's first start, and then updated only by manual request, as previous import will be used.

myActivity.getSharedPreferences("com.example.imported",0)
.edit()
.putString("The news",getTheNews())
.apply();

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Comments

[atuljangra]

I am also trying to do this , without hardcoding any string

[Alston]

But it works for some people stackoverflow.com/questions/6297159/… For me, sometimes it will crash if I change the text after use 'setContentView(~)'

[ceph3us]

to disabuse users I have included my answer to this question

[Mohammad Afrashteh]

It is so important to have the possibility of changing the resource file like the style. For example, when we want to change launcher theme that applicable even in the preview window.

[Mostafa Anssary]

drawable folder can't be modified at run time that not always true check this to see that you can may be for bitmap only

[Waqar UlHaq]

@Rob can you please share some code? How you achieved it?