How to change the Font Size in a whole Application programmatically, Android?

Question

I have created Spinner with the list of Font Sizes from \"8\" to \"46\" . I could be able to click the font Size and in a spinner it has shown me .

My need is, if i

Answer 1

To scale the font size of all components(mean whole application), there is pretty well approach which is implemented and tested trough several devices. This solution could be applied for cases like; declaring dp size unit statically(android sp by default) , scaling to desired font sizes and etc.

The solution is similar to answer given by Usama Saeed US but will cover all buggy cases.

Declare static util method which will scale font size.

    //LocaleConfigurationUtil.class
    public static Context adjustFontSize(Context context){
        Configuration configuration = context.getResources().getConfiguration();
        // This will apply to all text like -> Your given text size * fontScale
        configuration.fontScale = 1.0f;

        return context.createConfigurationContext(configuration);
    }

In your all activities, override the attachBaseContext and call util method in onCreate.

   @Override
    protected void attachBaseContext(Context newBase) {
        super.attachBaseContext(LocaleConfigurationUtil.adjustFontSize(newBase));
    }

   @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        LocaleConfigurationUtil.adjustFontSize(this);
    }

If you are using fragments then override onAttach method

@Override
public void onAttach(Context context) {
super.onAttach(LocaleConfigurationUtil.adjustFontSize(context));
}