public class MainActivity extends Activity {
    private final static int TESTED_DEVICE_DISPLAY_HEIGHT = 1280;
    private final static int TESTED_DEVICE_DISPLAY_WIDTH = 768;
    
    private final static float TESTED_DEVICE_SCALED_DENSITY = 3.0f;
    private final static float TESTED_DEVICE_DENSITY = 3.0f;
    
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(getProperContentView());
        
        // How to get display metrics for the tested device
        DisplayMetrics metrics = getResources().getDisplayMetrics();
        float density = metrics.density; //TESTED_DEVICE_DENSITY
        float scaledDensity = metrics.scaledDensity; //TESTED_DEVICE_SCALED_DENSITY
        float width = metrics.widthPixels; //TESTED_DEVICE_DISPLAY_WIDTH
        float height = metrics.heightPixels; //TESTED_DEVICE_DISPLAY_HEIGHT
        ...
    }
    
    private ViewGroup getProperContentView() {
        return ZOptimization.with(this)
                .layout(R.layout.activity_main)
                .onlyFor(ZOptimization.Device.PHONE) // Optimized for phone only, also TABLET or BOTH can be used.
                .exclude(ZOptimization.Type.ALL, R.id.login_button) // Disable optimization for specific ids.
                .exclude(ZOptimization.Type.TEXT, AppCompatButton.class) // Disable text size optimization for specific classes.
                .enable(false, true, true, true) // Enable/disable optimization types
                .config(new DeviceBuilder()
                        .applyDp(TESTED_DEVICE_DENSITY)
                        .applySp(TESTED_DEVICE_SCALED_DENSITY)
                        .testedScreen(TESTED_DEVICE_DISPLAY_WIDTH, TESTED_DEVICE_DISPLAY_HEIGHT))
                .execute();
    }
}

@Override
public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
   ViewGroup itemView = (ViewGroup)  LayoutInflater.from(parent.getContext())
           .inflate(R.layout.item_layout, parent, false);
 
   return new MyViewHolder(getProperContentView(itemView));
}
    
private ViewGroup getProperContentView(ViewGroup viewGroup) {
    return ZOptimization.with(viewGroup.getContext())
            .layout(viewGroup)
            .config(new DeviceBuilder()
                    .applyDp(TESTED_DEVICE_DENSITY)
                    .applySp(TESTED_DEVICE_SCALED_DENSITY)
                    .testedScreen(TESTED_DEVICE_DISPLAY_WIDTH, TESTED_DEVICE_DISPLAY_HEIGHT))
            .execute();
}