How to change colorPrimary programmatically with a color given from an API?

Question

I need to change the colorPrimary and colorAccent programmatically. The color values are fetched from a web service once we login to the application. These values will be any, because it is setting from a web application. So the same theme should be displayed in the mobile application too.

This is my theme

<style name="AppTheme" parent="Theme.MaterialComponents.Light.DarkActionBar">
    <item name="colorPrimary">@color/colorPrimary</item>
    <item name="colorPrimaryDark">@color/colorPrimaryDark</item>
    <item name="colorAccent">@color/colorAccent</item>
</style>

I searched everywhere and the answers are like, I need to create a number of different themes and switch between. But in my scenario, it is perfectly dynamic.

Answer 1

1. first create "res/values-v9/" and put there this file: styles.xml and regular "res/values" folder will be used with your styles.

2. put this code in your res/values/styles.xml:

<resources>
    <style name="AppTheme" parent="Theme.AppCompat.Light">
        <item name="colorPrimary">#000</item>
        <item name="colorPrimaryDark">#000</item>
        <item name="colorAccent">#000</item>
        <item name="android:windowAnimationStyle">@style/WindowAnimationTransition</item>
    </style>

    <style name="AppThemeDarkActionBar" parent="Theme.AppCompat.Light.DarkActionBar">
        <item name="colorPrimary">#000</item>
        <item name="colorPrimaryDark">#000</item>
        <item name="colorAccent">#000</item>
        <item name="android:windowAnimationStyle">@style/WindowAnimationTransition</item>
    </style>

    <style name="WindowAnimationTransition">
        <item name="android:windowEnterAnimation">@android:anim/fade_in</item>
        <item name="android:windowExitAnimation">@android:anim/fade_out</item>
    </style>
</resources>

3. in to AndroidManifest:

<application android:theme="@style/AppThemeDarkActionBar">

4. create a new class with name "ThemeColors.java"

public class ThemeColors {

    private static final String NAME = "ThemeColors", KEY = "color";

    @ColorInt
    public int color;

    public ThemeColors(Context context) {
        SharedPreferences sharedPreferences = context.getSharedPreferences(NAME, Context.MODE_PRIVATE);
        String stringColor = sharedPreferences.getString(KEY, "004bff");
        color = Color.parseColor("#" + stringColor);

        if (isLightActionBar()) context.setTheme(R.style.AppTheme);
        context.setTheme(context.getResources().getIdentifier("T_" + stringColor, "style", context.getPackageName()));
    }

    public static void setNewThemeColor(Activity activity, int red, int green, int blue) {
        int colorStep = 15;
        red = Math.round(red / colorStep) * colorStep;
        green = Math.round(green / colorStep) * colorStep;
        blue = Math.round(blue / colorStep) * colorStep;

        String stringColor = Integer.toHexString(Color.rgb(red, green, blue)).substring(2);
        SharedPreferences.Editor editor = activity.getSharedPreferences(NAME, Context.MODE_PRIVATE).edit();
        editor.putString(KEY, stringColor);
        editor.apply();

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) activity.recreate();
        else {
            Intent i = activity.getPackageManager().getLaunchIntentForPackage(activity.getPackageName());
            i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
            activity.startActivity(i);
        }
    }

    private boolean isLightActionBar() {// Checking if title text color will be black
        int rgb = (Color.red(color) + Color.green(color) + Color.blue(color)) / 3;
        return rgb > 210;
    }
}

5. MainActivity:

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        new ThemeColors(this);
        setContentView(R.layout.activity_main);
    }

    public void buttonClick(View view){
        int red= new Random().nextInt(255);
        int green= new Random().nextInt(255);
        int blue= new Random().nextInt(255);
        ThemeColors.setNewThemeColor(MainActivity.this, red, green, blue);
    }
}

To change color, just replace Random with your RGB, Hope this helps.

enter image description [here]

There is a complete example: ColorTest.zip

You can have a look at this GitHub project from Rumit Patel.